Structural Aspects of Pt(η3–P1C2X1C2P2)(Y) Derivative Types

Milan Melník; Veronika Mikušová; Peter Mikuš

doi:10.3390/cryst13091340

Abstract

In this structural study, structural data are classified and analyzed for almost seventy complexes of the general formula Pt(η³–P¹X¹P²)(Y) (X¹ = O, N, C, S, Si) and (Y = various monodentate ligands), in which the respective η³–P¹X¹P² ligand forms a pair of five-membered metallocyclic rings with a common X¹ atom of the P¹C₂X¹C₂P² type. The present complexes crystallize in five crystal systems: trigonal (1×), tetragonal (1×), orthorhombic (11×), triclinic (18×), and monoclinic (39×). In 69 complexes, a η³ ligand with monodentate Y constructs a distorted square planar geometry around each Pt(II) atom. There is only one complex in which Pt(η³–P¹Si¹P²)(P³Ph₃) constructs a trigonal–pyramidal geometry around a Pt(II) atom. The three P atoms construct a trigonal plane, and the Si atom occupies a pyramid. The structural data are discussed from various points of view, including the covalent radii of the atoms, the degree of distortion, and trans-influence. The trans-effect on the Pt-L bond distance also affects the L-PT-L bond angles, as well as the distortion of square planar geometry around Pt(II) atoms.

Keywords:

structure; heterotridentate; Pt(η³–P¹C₂X¹C₂P²)(Y); trans-influence; review

1. Introduction

The chemistry of platinum coordination complexes has been intensively studied and developed for more than five decades, focusing on the relationship between structure and reactivity. The chemistry of platinum is important in the fields of biochemistry [1], catalysis [2], spectroscopy [3,4], and coordination theory. Very recently, Horiuchi and Umakoshi published a review that focused on the importance of and advances in the synthetic, structural, thermodynamic, electronic, and photophysical properties of Pt-based heteropolynuclear complexes [5].

Significant attention has been paid to organomonophosphines, representing soft donor ligands in the chemistry of platinum. There are a large number of published structural studies on such complexes that have been classified and analyzed [6]. Another group of related structural studies is devoted to Pt(II) complexes with organodiphosphines [7,8]. Recently, we analyzed and classified structural data for the following compositions: Pt(η⁴–P₄L), Pt(η⁴–P₃ SiL), Pt(η⁴–P₂N₂L), Pt(η⁴–P₂S₂L), Pt(η⁴–P₂C₂L), Pt(η⁴–PN₃L), and Pt(η⁴–PN₂OL) [9]. As can be seen, P-donor ligands prevail by far. η⁴–ligands form 10-, 11-, 12-, 14-, and 16-membered metallocycles. A distorted square planar geometry around Pt(II) atoms with cis-configuration prevails by far.

From an application point of view, multifunctional ligands responsible for secondary catalyst–substrate interactions over the course of a catalytic transformation play increasingly important roles in contemporary catalysis, as has been demonstrated also within these groups of platinum complexes with P-donor ligands. Pincer-type complexes constitute a family of compounds that have recently attracted significant interest. They play important roles in organometallic reactions and mechanisms, catalysis, and the design of new materials (see, e.g., reviews [10,11,12,13,14,15,16]). The high thermal stability of such complexes, particularly those based on an aromatic backbone, permits their use as catalysts at elevated temperatures in various catalytic applications. Bulky bis-chelating pincer-type ligands are effective in the stabilization of highly unsaturated cationic complexes and the stabilization of reactive species [10,11,12,13,14,15,16,17].

As a continuation of the investigation of platinum complexes with P-donor ligands, this structural study aims to classify and analyze the structural parameters of heterotridentate organodiphosphines in monomeric four-coordinated platinum complexes of the Pt(η³–P¹X¹P²)(Y), (X¹ = O¹L, N¹L, C¹L, S¹L, or Si¹L) type, in which each tridentate ligand creates a pair of “equal” five-membered rings with a common X¹ atom of the P¹C₂X¹C₂P² type. The application potentialities of these ligands and their complexes are reviewed, as well, to demonstrate the prevailing areas of their practical use.

2. Pt(η³–P¹C₂X¹C₂P²)(Y), (X¹ = O¹,N¹, C¹, S¹, or Si¹)

There are 69 complexes in which heterotridentate organodiphosphines create a pair of “equal” five-membered metallocyclic rings with a common X¹ atom. These tridentate ligands with monodentate Y ligands construct a square planar geometry with various degrees of distortion around Pt(II) atoms. These complexes are centrosymmetric. Groups of X¹ = O¹, N¹, or C¹ structures, which were mentioned for several representatives in our previous work devoted to any type of n-member metallocycle rings (n = 5,6,7) but different types of atoms between P¹ and X¹ [18], are analyzed in detail in this work, along with a new group of X¹ = S¹, Si¹ structures, highlighting structural aspects related to distortion. The complexes are described in detail via the relevant structural data gathered in Table 1, Table 2 and Table 3 for Pt{η³–P¹X¹P²}(Y), (X¹ = O¹, N¹), (Y = C²L, N²L, Cl, P³L); Pt{η³–P¹C¹P²}(Y), (Y = O²L, N²L, CL, Cl, Br); and Pt(η³–P¹X¹P²)(Y), (X¹ = S¹ or Si¹), (Y = C²L, Cl, P³L, I, H, O²L) structural subgroups, respectively. The chemical structures of particular complexes in these subgroups are gathered in Supplementary Materials and Tables S1–S3 therein. The majority of the cited works describe the synthesis and structural characterization of various ligands and their Pt(II) complexes (just one example of a square planar Pt(0) complex). Pincer ligands and their Pt(II) complexes dominate in the presented application examples; they are all focused on various aspects of synthesis and catalysis performance, as can be seen from brief summaries in Tables S1–S3.

Table 1. Crystallographic and structural data for Pt{η³–P¹X¹P²}(Y), (X¹ = O¹, N¹), (Y = C²L, N²L, Cl, P³L) complexes ^a.

Table 2. Crystallographic and structural data for Pt{η³-P¹C¹P²}(Y), (Y = O²L, N²L, CL, Cl, Br) complexes ^a.

Table 3. Crystallographic and structural data for Pt(η³–P¹X¹P²)(Y), (X¹ = S¹ or Si¹), (Y = C²L,Cl,P³L,I,H,O²L) complexes ^a.

2.1. Pt(η³–P¹O¹P²)(P³)

Monoclinic [Pt{η³-Ph₂P(C₁₅H₁₂O)PPh₂}{η¹–P³(C₅H₄N)(Ph)₂}](CF₃SO₃)₂•0.5H₂O [19] (at 150 K) is the only example of the P¹C₂O¹C₂P² metallocycle type. The structural data are summarized in Table 1. The chemical structure and practical application of this particular complex are presented in Table S1. The heterotridentate η³-P¹O¹P² ligand with monodentate P³L creates a distorted square planar geometry around a Pt(II) atom.

The total mean Pt–L bond distance elongates in the following sequences:

Pt (η³-P¹O¹P²)(Y), Y = P³L (1 example): Pt–L: 2.189 (3) Å (O¹, trans to P³) < 2.239 (2) Å (P³) < 2.302 (2,11) Å (P^1,2, mutually trans)

2.2. Pt(η³–P¹N¹P²)(Y), (Y = N² L, (x1), CL(x9), Cl(x7), P³L(x2))

There are nineteen examples of the P¹C₂N¹C₂P² metallocyclic type with a common N¹ atom, and their structural data are summarized in Table 1. The chemical structures and practical applications of these particular complexes are presented in Table S1. Monoclinic [Pt{η³-Ph₂P(C₁₂H₈N)PPh₂}(N²C₅H₅)]CF₃SO₃.toluene [20] is the only example in which a N² donor ligand completed a square planar geometry around a Pt(II) atom (PtP¹N¹P²N²). The structure of [Pt{η³-Ph₂P(C₁₂H₈N)PPh₂}(N²C₅H₅)]⁺ [20] is shown in Figure 1 as an example.

Figure 1. Structure of [Pt{η³-Ph₂P(C₁₂H₈N)PPh₂}(py)] [20].

In the following eight complexes, triclinic [Pt{η³-Bu^t₂P(C₇H₇N)PBu^t₂}(CH₃)]Cl (at 100 K), monoclinic [Pt{η³-Bu^t₂P(C₇H₆N)PBu^t₂}(CH₃)] [21] (at 100 K), monoclinic [Pt{η³-Ph₂P(C₇H₇N)PPh₂}{C(=O)Et}]BF₄.(CH₂Cl₂)₅ [22] (at 100 K), triclinic [Pt{η³-Ph₂P(C₇H₇N)PPh₂}(CH₂CHO)]BF₄ [22], triclinic [Pt{η³-Ph₂P(C₇H₇N)PPh₂}(CH=CHPh)]BF₄ [23], monoclinic [Pt{η³-Prⁱ²P(C₁₂H₇F₂N)PPrⁱ²}(C₆H₄F)]B(C₆H₅)₄ (at 110 K) and monoclinic [Pt{η³-Pri²P(C₁₂H₇F₂N)PPrⁱ²}. (p-toluene)]B(C₆H₅)₄ [24] (at 110 K), and monoclinic [Pt{η³-Ph₂P(C₇H₇N)PPrⁱ²}(η¹-C₁₁H₁₅NO₃)]BF₄ [25] and a η³-P¹N¹P² ligand with a monodentate CL create a distorted square planar geometry around a Pt(II) atom (PtP¹N¹P²C).

There are seven complexes, monoclinic [Pt{η³-Ph₂P(C₁₂H₈N)PPh₂}(Cl)](C₆H₆)₅ [20], trigonal [Pt{η³-Bu^t₂P(C₇H₇N)PBu^t₂}(Cl)]Cl [21], orthorhombic [Pt{η³-Bu^t₂P(C₇H₆N)PBu^t₂}(Cl)] [21] (at 120 K), monoclinic [Pt{η³-Prⁱ₂P(C₁₂H₆F₂N)PPrⁱ₂}(Cl)]CHB₁₁Cl₁₁ [24] (at 110 K), monoclinic [Pt{η³-Ph₂P(C₁₄H₁₂N)PPrⁱ₂}(Cl)]C₆H₆ [26] (at 183 K) and triclinic [Pt{η³-Ph₂P(C₁₄H₁₂N)Pcy₂}(Cl)]C₆H₆ [26] (at 183 K), and monoclinic [Pt{η³-Ph₂P(C₇H₈N)PPh₂}(Cl)] [27] in which Cl⁻ anions complete inner coordinate spheres (PtP¹N¹P²Cl).

In the remaining two complexes, triclinic [Pt{η³-(η²-(C₂₄H₄₄)P(C₇H₆N)P(C₂₄H₄₄)} (PPh₃)].2CH₂Cl₂ [28] (at 103 K) and monoclinic [Pt{η³-(η²-C₁₈H₂₈)P(C₇H₆N)P(η²-C₁₈H₂₉)}(P³cy₃)] [29] (at 103 K), a monodentate P³L is involved (PtP¹N¹P²P³).

The total mean Pt-L bond distance elongates in the following sequences:

Pt (η³-P¹N¹P²)(Y), Y = N²L, CL, Cl, P³L (19 examples): Pt–N¹: (trans to Y): 2.024 (3) Å (N²) < 2.077 (2,5) Å (P³) < 2.128 (2,70) Å (C) < 2.201 (3,26) Å (Cl); Pt–Y: (trans to N¹): 2.056 (3) Å (N²) < 2.072 (2,85) Å (C) < 2.277 (2,5) Å (P³) < 2.316 (2,17) Å (Cl); Pt–P^1,2: (mutually trans) is 2.287 (2,17) Å

2.3. Pt(η³–P¹C¹P²)(Y), (Y = OL (x4), NL(x4), C²L (x9), Cl (x12), Br (x2))

There are over thirty examples of the P¹C₂C¹C₂P² metallocycle type, and their structural data are summarized in Table 2. The chemical structures and practical applications of these particular complexes are presented in Table S2. In four complexes, monoclinic [Pt{η³-(CF₃)₂P(C₈H₇)P(CF₃)₂}(H₂O)].SbF₆ [30], triclinic [Pt{η³-Ph₂P(C₈H₇)Ph₂P}(H₂O)]CF₃SO₃ [31], triclinic [Pt{η³-Ph₂P(C₈H₇)PPh₂}(OMe)]0.5C₆H₆ [31], and orthorhombic [Pt{η³-Prⁱ₂P(C₂₀H₁₁)PPrⁱ₂}(OOCCF₃)] [32] (Figure 2), a monodentate OL ligand completed a square planar geometry (PtP¹C¹P²O).

Figure 2. Structure of [Pt{η³-Pri₂P(C₂₀H₁₁)PPrⁱ₂}(OOCCF₃)] [32].

In four complexes, monoclinic [Pt{η³-(CF₃)₂P(C₈H₇)P(CF₃)₂} (NC₅H₅)]B(C₆H₅)₄ [30], orthorhombic [Pt{η³-Ph₂P(C₂₀H₁₃O₄)PPh₂}(N≡CCH₃)]BF₄ [32], monoclinic [Pt{η³-Ph₂P(C₂₀H₁₁O₂)PPh₂}(NC₅H₅)]Cl}](NC₅H₅) [33], and monoclinic [Pt{η³-Ph₂P(C₂₀H₁₁O₄)PPh₂} (N≡CCH₃)]BF₄. CH₂Cl₂ [33], monodentate NL ligands completed the inner coordination sphere PtP¹N¹P²N².

There are nine complexes, tetragonal [Pt{η³-Ph₂P(C₂₄H₁₉O₂)PPh₂}(CN)] [34], triclinic [Pt{η³-(CF₃)₂P(C₈H₇)P(CF₃)₂}(CO)]SbF₆ [35], monoclinic [Pt{η³-(CF₃)₂P(C₈H₇)P(CF₃)₂}(CH₃)] [35], monoclinic [Pt{η³-Prⁱ₂P(C₈H₇)PPrⁱ₂}(CO)]CF₃SO₃ 0.5C₆H₆ [36], monoclinic [Pt{η³-Bu^t₂P(C₈H₇)PBu^t₂}(η¹-CHOMe)]CF₃SO₃.thf [36], orthorhombic [Pt{η³-Bu^t₂P(C₁₂H₉)PBu^t₂}(CO)]BF₄ [37], monoclinic [Pt{η³-Ph₂P(C₈H₇)PPh₂}(η¹-C₁₂H₁₉N₂)] [38], monoclinic [Pt{η³-Ph₂P(C₆H₇N₂)PPh₂}(η¹-C₃F₂)] [39], and monoclinic [Pt{η³-Ph₂P(C₈H₇)PPh₂}(η¹-C₁₂H₂₁N₂)]2(BF₄) [40], in which a monodentate C²L ligands are involved (PtP¹C¹P²C²).

In twelve complexes, triclinic [Pt{η³-Ph₂P(C₂₀H₁₁O₂)PPh₂}(Cl)](CH₃CN)₄ [33], monoclinic [Pt{η³-Ph₂P(C₂₄H₁₉O₂)PPh₂}(Cl)] [34], monoclinic [Pt{η³-(CF₃)₂P(C₈H₇)P(CF₃)₂}(Cl)]1.5C₆H₁₄ [35], orthorhombic [Pt{η³-Bu^t₂P(C₈H₇)PBu^t₂}(Cl)] [36], monoclinic [Pt{η³-Bu^t₂P(C₁₂H₉)PBu^t₂}(Cl)] [37], monoclinic [Pt{η³-Bu^t₂P(C₈H₇)PBu^t₂}(Cl)] [41], triclinic [Pt{η³-Prⁱ₂P(C₈H₇)PPrⁱ₂}(Cl)] [42], monoclinic [Pt{η³-Ph₂P(C₁₄H₇)PPh₂}(Cl)] [43], monoclinic [Pt{η³-Ph₂P(C₈H₇)PPh₂}(Cl)]CH₃CN [44], orthorhombic [Pt{η³-Ph₂P(C₁₈H₁₁O₈)PPh₂}(Cl)]CH₃CN [44], orthorhombic [Pt{η³-Ph₂P(C₁₈H₁₁O₈)PPh₂}(Cl)]CH₂C_l2 [45], and monoclinic [Pt{η³-Prⁱ₂P(C₂₀H₁₁)PPrⁱ₂}(Cl)](CH₃CN)₂ [46], a Cl⁻ anion completed inner coordination spheres around each Pt(II) atom (PtP¹C¹P²Cl).

A Br⁻ anion is involved in two monoclinic complexes, [Pt{η³-Ph₂P(C₈H₇)PPh₂}(Br)] [57] and [Pt{η³-Bu^t₂P(C₈H₇)PBu^t₂}(Br)] [47].

The total mean PL-L bond distance elongates in the following sequences:

Pt (η³-P¹C¹P²)(Y), Y = OL, NL, C²L Cl, Br (31 examples): Pt–C1: (trans to Y): 2.001 (3,8) Å (N) < 2.027 (2,8) Å (O) ~ 2.027 (2,6) Å (Br) < 2.031 (2,12) Å (Cl) < 2.049 (2) Å (C²); Pt–Y: (trans to C¹): 2.065 (7,12) Å (C²) < 2.085 (2,12) Å (N) < 2.132 (2,9) Å (O) < 2.400 (2,16) Å (Cl) < 2.467 (1,10) Å (Br); Pt–P^1,2: (mutually trans) is 2.75 (2,12) Å.

2.4. Pt(η³–P¹S¹P²)(Y), (Y = CH₃ (x1), Cl (x2), P³Ph₃ (x2), I (x1))

There are six complexes in which each heterotridentate ligand creates a P¹C₂S¹C₂P² metallocycle. Monoclinic [Pt{η³-Ph₂P(C₆H₄)S(=O)(C₆H₄)PPh₂}(CH₃)]PF₆.CH₃CN [48] (at 100 K; Figure 3) is the only example with a (PtP¹S¹P²C) chromophore. In monoclinic [Pt{η³-Ph₂P(C₆H₄)S(=O)(C₆H₄)PPh₂}(Cl)]PF₆.CH₃CN [48] and triclinic [Pt{η³-Ph₂P(CH₂)₂S(=O)(CH₂)₂PPh₂}(Cl)]ClO₄ [49], the Cl⁻ anion completed a square planar geometry (PtP¹S¹P²Cl). The structural data are summarized in Table 3. The chemical structures and practical applications of these particular complexes are presented in Table S3.

Figure 3. Structure of [Pt{η³-Ph₂P(C₆H₄)S(=O)(C₆H₄)PPh₂}(CH₃)] [49].

In triclinic [Pt{η³-Ph₂P(C₆H₄)S(=O)(C₆H₄)PPh₂}(P³Ph₃)]0.5.CH₂Cl [48] (at 100 K) and orthorhombic [Pt{η³-Ph₂P(CH₂)₂S(CH₂)₂PPh₂}(P³Ph₃)]ClO₄ [50] (at 100 K), the P³Ph₃ are involved (PtP¹S¹P²P³).

In another triclinic [Pt{η³-Ph₂P(C₂₃H₂₈S)PPh₂}(I)].1.74 CH₂Cl₂ [51] (at 150 K), the I⁻ anion is involved (PtP¹S¹P²I).

The total mean PL-L bond distance elongates in the sequences:

Pt (η³-P¹S¹P²)(Y), Y = CL, Cl, P³L, I (6 examples): Pt–S¹: (trans to Y): 2.187 (2,5) Å (Cl) < 2.256 (2) Å (I) < 2.268 (2) Å (C) < 2.328 (2,15) Å (P³); Pt–Y: (trans to S¹): 2.093 (2) Å (C) < 2.285 (2,3) Å (P³) < 2.317 (2,5) Å (Cl) < 2.510 (1) Å (I); Pt–P^1,2: (mutually trans) is 2.300 (4,30) Å.

2.5. Pt(η³–P¹Si¹P²)(Y), (Y = H (x2), OL (x1), NL (x1), CL (x1), Cl (x5), P³L (x1))

There are fourteen complexes in which each heterotridentate ligand creates a pair of “equal” five-membered metallocyclic rings with a common Si¹ atom of the P¹C₂Si¹C₂P² type. The structural data are summarized in Table 3. The chemical structures and practical applications of these particular complexes are presented in Table S3. In two monoclinic [Pt{η³-cy₂P(C₆H₄)Si(Me)(C₆H₄)Pcy₂}(H)].0.5 pentane [52] (at 150 K) and [Pt{η³-cy₂P(C₆H₄)Si(Me)(C₆H₄)Pcy₂}(H)].1.25 pentane [52] (at 93 K), hydride completed a square planar geometry (PtP¹Si¹P²H).

Triclinic [Pt{η³-Ph₂P(C₆H₄)Si(Me)(C₆H₄)PPh₂}(OEt₂)]{B(C₆F₅)₃ (CH₂Ph)}.OEt₂ [53] (Figure 4) is the only example with a monodentate OEt₂ ligand (PtP¹Si¹P²O).

Figure 4. Structure of [Pt{η³-Ph₂P(C₆H₄)Si(Me)(C₆H₄)PPh₂}(OEt₂)] [53].

In another triclinic [Pt{η³-Prⁱ₂P¹(C₆H₄)Si¹(C₆H₄PPrⁱ₂)(C₆H₄)P²Prⁱ₂}(NC₅H₅)]B(C₈H₃F₆)₄ [58] (at 100 K), a monodentate NC₅H₅ is involved (PtP¹Si¹P²N).

In the following four complexes: triclinic [Pt{η³-cy₂P(C₆H₄)Si(Me)(C₆H₄)Pcy₂}(Ph)]OEt₂ [53] (at 173 K), triclinic [Pt{η³-Ph₂P(C₆H₄)Si(Me)(C₆H₄)PPh₂}(CH₂Ph)]CH₂Cl₂ [53] (at 193 K), triclinic [Pt{η³-Prⁱ₂P)(C₆H₄)Si(OH)(C₆H₄)PPrⁱ₂)}(CO)]B(C₆F₅)₄ [54] (at 120 K), and orthorhombic [Pt{η³-Prⁱ₂P(C₆H₄)Si(H)(C₆H₄)PPrⁱ₂}(mes)] [55] (at 110 K), monodentate CL ligands are involved (PtP¹Si¹P²C).

In the following five complexes: monoclinic [Pt{η³-Ph₂P(C₆H₄)Si(Me)(C₆H₄)PPh₂}(Cl)] [53] (at173 K), orthorhombic [Pt{η³-Ph₂P(C₆H₄)Si(Me)(C₆H₄)PPh₂}(ClAlCl₃)](C₆H₅F)₂ [53] (at 193 K), monoclinic [Pt{η³-Prⁱ₂P(C₆H₄)Si(OH)(C₆H₄)PPrⁱ₂}(Cl)] [54] (at 120 K), monoclinic [Pt{η³-Prⁱ₂P(C₆H₄)Si(H)(C₆H₄)Pcy₂}(Cl)] [55] (at 110 K), and monoclinic [Pt{η³-cy₂P(C₆H₄)Si(Me)(C₆H₄)Pcy₂}(Cl)] [56] (at 110 K), tridentate P¹Si¹P² with Cl⁻ anions construct inner coordination spheres around each Pt(II) atom (PtP¹Si¹P²Cl).

The total mean PL-L bond distance elongates in the following sequences:

Pt (η³-P¹Si¹P²)(Y), Y = H, OL, NL, CL, Cl, P³L (19 examples): Pt–Si¹: (trans to Y): 2.276 (2) Å (O) < 2.279 (2,6) Å (Cl) < 2.315 (2) Å (N) < 2.331 (2,5) Å (H) < 2.339 (2,17) Å (C) < 2.369 (2) Å (P³); Pt–Y: 1.51 (1,2) Å (H) < 2.122 (2,6) Å (C) < 2.222 (2) Å (N) < 2.282 (2) Å (O) < 2.316 (2) Å (P³) < 2.451 (2,13) Å (Cl); Pt–P^1,2: (mutually trans) is 2.289 (2,32) Å.

The structure of monoclinic [Pt{η³-Ph₂P¹(C₆H₄)Si¹(Me)(C₆H₄)P²Ph₂}(P³Ph₃)] [59] (at 123 K) is shown in Figure 5. In a distorted trigonal–pyramidal geometry, three P atoms construct a trigonal plane, and the Si¹ atom occupies a pyramid. The heterotridentate P¹Si¹P² ligand forms a pair of “equal” five-membered metallocyclic rings with a common Si¹ atom of the P¹C₂Si¹C₂P² type, with the mean P¹–Pt–Si¹/Si¹–Pt–P² bite angles of 83.3 (1,8)°. The values for the remaining angles are 120.7 (2)° (P¹–Pt–P²), 119.6 (2,2.4)° (P¹–Pt–P³/P³–Pt–P²), and 108.9 (2)° (Si¹–Pt–P³). The Pt-L bond distance elongates in the following order: 2.290 (2.11) Å (Pt–P¹, Pt–P²) < 2.318 (2) Å (Pt–P³) < 2.369 (2) Å (Pt–Si¹). This is the only example of such geometries.

Figure 5. Structure of [Pt{η³-Ph₂P(C₆H₄)Si(Me)(C₆H₄)PPh₂}(PPh₃)] [59].

3. Conclusions

This review evaluates seventy Pt(II) complexes in which inner coordination spheres are constructed by heterotridentate organodiphosphines (η³−P¹X¹P²) (Y), (X¹ = OL, NL, CL, SL or SiL) with variable monodentate donor ligands. These complexes crystallized in five crystal systems: trigonal (×1), tetragonal (×1), orthorhombic (×11), triclinic (×18), and monoclinic (×39).

The structures of the complexes are similar. Each heterotridentate organodiphosphine ligand creates a pair of “equal” five-membered metallocyclic rings with a common X¹ atom of the P¹C₂X¹C₂P2 type.

The sum of four (Pt-P(x2) + Pt-X¹ + Pt-Y) bond distances grows with the covalent radius of the Y atom in the following sequences:

PtP¹N¹P²Y: 8.65 Å (Y = N) < 8.76 Å (C) < 8.91 Å (Cl) < 9.00 Å (P³);

PtP¹C¹P²Y: 8.64 Å (Y = N) < 8.66 Å (C²) < 8.98 Å (Cl) < 9.05 Å (Br);

PtP¹S¹P²Y: 8.91 Å (Y = C) < 9.13 Å (Cl) < 9.20 Å (P³) < 9.39 Å (I);

PtP¹Si¹P²Y: 8.35 Å (Y = H) < 9.15 Å (O) < 9.17 Å (N) < 9.30 Å (Cl).

The total mean values of the L-Pt-L bond angles are 83.1 (2,2.7)° (P¹-Pt-X¹/X¹-Pt-P²), 163.2 (2,3.5)° (P¹-Pt-P²), 96.2 (2,2.5) ° (P¹-Pt-Y/Y-Pt-P²), and 175.7° (2,3.9) (X¹-Pt-Y).

There are two exceptions—PtP¹C¹P²O and PtP¹Si¹P²C—with the sums of 8.71 and 9.03 Å that do not follow the covalent radius of the Y atom. There are two reasons for this discrepancy: trans-influence of C¹ vs. O and Si¹ vs. C, and the types of ligand H₂O and OMe in the former and CO and CN in the latter.

It is well known that in four-coordinated Pt(II) atoms, there is a preference for square planar geometry with different degrees of distortion. A simple metric to assess the molecular shape and degree of distortion is the parameter Τ₄ for square planar geometry according to the following equation: Τ₄ = 360 − (α + β)/141 [60]. The value of Τ₄ for a perfect square planar geometry is zero. The degree of distortion for a square planar geometry around Pt(II) atoms grows in the following sequences (according to Y):

Pt(η³−P¹S¹P²)(Y):0.105 (Y = C²) < 0.120(I) < 0.138 (Cl) < 0.143 (P³);

The total mean value of τ₄ is 0.125;

Pt(η³−P¹C¹P²)(Y):0.130(C^l) < 0.133(C²) < 0.138 (Br) < 0.146 (O²) < 0.166 (N²);

The total mean value of τ₄ is 0.143;

Pt(η³−P¹N¹P²)(Y):0.115(Cl) < 0.125(N²) < 0.140 (C²) < 0.204 (P³);

The total mean value of τ₄ is 0.146;

Pt(η³−P¹C¹P²)(Y):0.163 (P³);

Pt(η³−P¹Si¹P²)(Y):0.115(O²) < 0.169(H) < 0.171 (N²) < 0.176 (Cl) < 0.186 (C²);

The total mean value of τ₄ is 0.163.

The trans-α-X¹-Pt-Y and β-P¹-Pt-P² bond angles are responsible for distortion of square planar geometry around Pt(II) atoms. While the donor atoms of α-X¹-Pt-Y angles exhibit a wide variety of soft (H, C, S, P, Si, I), borderline (Br), and hard (O, N, Cl), the donor atoms of β-P¹-Pt-P² angles are only soft. The soft atom ligand has a larger trans-effect than the borderline or hard ones. The trans-effect on a Pt bond distance also affects the L-Pt-L bond angles.

If we take trans-effect into account, the respective trans-α-X¹-Pt-Y and β-P¹-Pt-P² angles open, and the distortion (τ₄) diminishes in the order (means values) (Table 4).

Table 4. Total mean values of angles and τ₄ of the respective complexes according to the plasticity of atoms.

Structural information about platinum complexes is a prerequisite to properly understanding their roles in chemistry, biology, medicine, etc. Hence, this structural study provides relevant and rationally classified data on the evaluated group of Pt(II) complexes (Pt(η³–P¹C₂X¹C₂P²)(Y)), which is helpful for the proper interpretation of results from the areas where such complexes were applied (here, mainly toward their catalytic activity).

Supplementary Materials

The following are available at https://www.mdpi.com/article/10.3390/cryst13091340/s1, Table S1: Structures and applications of Pt{η³–P¹X¹P²}(Y), (X¹ = O¹,N¹), (Y = C²L,N²L,Cl,P³L) complexes; Table S2: Structures and applications of Pt{η³-P¹C¹P²}(Y), (Y = O²L,N²L,CL,Cl,Br) complexes; Table S3: Structures and applications of Pt(η³–P¹X¹P²)(Y), (X¹ = S¹ or Si¹) (Y = C²L,Cl,P³L,I,H,O²L) complexes.

Author Contributions

Conceptualization, M.M. and P.M.; methodology M.M. and P.M.; writing—original draft preparation, M.M. and P.M.; data curation, M.M.; writing—review and editing, V.M.; supervision, M.M. and P.M.; funding acquisition, P.M. All authors have read and agreed to the published version of the manuscript.

Funding

This work was supported by the following projects: VEGA 1/0514/22 and VEGA 1/0146/23.

Data Availability Statement

The data supporting the reported results can be requested from author M.M.

Acknowledgments

This work was supported by the Faculty of Pharmacy, Comenius University Bratislava.

Conflicts of Interest

The authors declare no conflict of interest.

Abbreviations

Bu^t₂P(C₁₁H₁₆N₃)PBu^t₂	(N,N’-3,3,5 triethylpyridine-2,6-(1H,2H)-diylidene)bis(di-t-butyl(phosphinusamidato)
Bu^t₂P(C₁₂H₉)PBu^t₂	(1,3-bis(di-t-butylphosphinomethyl)-2-naphtyl
Bu^t₂P(C₇H₆N)PBu^t₂	(6-((di-t-butylphosphino)methyl-2-((di-t-butyl phosphino)methylene)-1,2-dihydropyridine-1-yl)
Bu^t₂P(C₇H₇N)PBu^t₂	(2,6-bis(di-t-butylphosphino)methyl)pyridine
(CF₃)₂P(C₈H₇)P(CF₃)₂	(2,6-bis(bis(trifluoromethyl)phosphinomethyl) phenyl)
(η²–C₁₈H₂₈)P(C₇H₆N)P(η¹–C₁₈H₂₄)	(2-((5,7-di-t-butyl-3,3-dimethyl-2,3-dihydro-14-phosphindol-1-yl)methylene)-6-(((2,4,6-tri-t-butylphenylphosphino)methyl)-1,2-dihydro pyridinyl) undecachloro-carba-undecaborane
cy₂P(C₆H₄)Si(Me)(C₆H₄)Pcy₂	((methylsilanediyl)di-2,1-phenylene)bis(dicyclohexylphosphine))
Pcy₃	tricyclohexylphosphino
Ph₂P(C₁₂H₈N)PPh₂	(2,2’-bis (diphenylphosphino)diphenylamido)
Ph₂P(C₁₄H₇)PPh₂	(1,8-bis(diphenylphosphino)-9-anthryl)
Ph₂P(C₁₄H₇O₂)PPh₂	(1,8-bis(diphenylphosphino)-9-hydroxy-10-oxo-9,10-dihydroanthracen-9-yl)
Ph₂P(C₁₅H₁₂O)PPh₂	((9,9-dimethyl-9H-xanthene-4,5-diyl)bis (diphenylphosphine)-diphenyl(2-pyridyl) phosphine
Ph₂P(C₁₈H₁₉O₈)PPh₂	(2,6-bis(1-(diphenylphosphino)-3-methoxy-2-(methoxycarbonyl)-3-oxopropylphenyl)
Ph₂P(C₂₀H₁₁O₂)PPh₂	(13,16-bis(diphenylphosphino)-3,6-dihydroxypentacyclo [6.6.6.O^2,7.O^9,14.O^15,20]icosa-2,4,6,9,11,13,15,17,19-nonaen-1-yl)
Ph₂P(C₂₀H₁₃O₄)PPh₂	(3,13-bis(diphenylphosphino)-15,16-bis(methoxy-carbonyl)tetracyclo[6.6.6.2 O^2,7.O^9,14]hexadeca-2,4,6,9,11,13,15-heptaen-1-yl)
Ph₂P(C₂₃H₂₈S)PPh₂	((9,9-dimethyl-2,7-bis(t-butyl)-9H-thioxantene-4,5-diyl)bis(diphenylphosphine)
Ph₂P(C₆H₄)S(=O)(C₆H₄)PPh₂	((sulfinydi-2,1-phenylene)bis(diphenylphosphine)
Ph₂P(C₈H₇)PPh₂	(2,6-bis((diphenylphosphino)methyl)phenyl)
Ph₂P(CH₂)₂S(CH₂)₂PPh₂	(bis(2-(diphenylphosphino)ethyl)sulfide)
PPh₃	triphenylphosphine
Prⁱ₂P (C₂₀H₁₁)PPrⁱ₂	(3,13-bis(diisopropylphosphino)-pentacyclo [6.6.6.O^2,7.O^9,14.O^15,20]icosa-2,4,6,9,11,13,15,17,19-heptaen-1-yl)
Prⁱ₂P(C₁₂H₆F₂N)PPrⁱ₂	(2-(diisopropylphosphino)-N-(2-(diisopropyl-phosphino)-4-fluorophenyl)-4-fluoroanilinato)
Prⁱ₂P(C₁₂H₇F₂N)PPrⁱ₂	(2-(diisopropylphosphino)-N-(2-(diisopropyl-phosphino)-4-fluorophenyl)-4-fluoroaniline)
Prⁱ₂P(C₁₄H₁₂N)PPh₂	(bis(2-(di-isopropylphosphino)-4-methyl-phenyl)(2-((diphenylphosphino)-4-methyl-phenyl)amide)
Prⁱ₂P(C₆H₄)Si(C₁₂H₄₆P)(C₆H₄)PPrⁱ₂	(tris(2-(diisopropylphosphino)phenyl)silyl)
Prⁱ₂P(C₆H₄)Si(H)(C₆H₄)PPrⁱ₂	((silanediyldi-2,1-phenylene)bis(diiso-propyl phosphine))

References

Rosenberg, B.; Van Camp, L.; Trasko, Y.E.; Mansour, V.H. Platinum Compounds: A New Class of Potent Antitumour Agents. Nature 1969, 222, 385–386. [Google Scholar] [CrossRef]
Ashiq, M.; Danish, M.; Mohsin, M.; Bari, S.; Mukhtar, F. Chemistry of Platinum and Palladium Metal Complexes in Homogeneous and Heterogeneous Catalysis: A Mini Review. Int. J. Sci. Basic. Appl. Res. 2013, 7, 50–61. Available online: http://gssrr.org/index.php?journal=JournalOfBasicAndApplied&page=article&op=view&path%5B%5D=1134 (accessed on 25 May 2023).
Chaaban, M.; Zhou, C.; Lin, H.; Chyic, B.; Ma, B. Platinum(ii) binuclear complexes: Molecular structures, photophysical properties, and applications. J. Mater. Chem. C 2019, 7, 5910–5924. [Google Scholar] [CrossRef]
Santos, T.M.R.; Andolpho, G.A.; Tavares, C.A.; Gonçalves, M.A.; Ramalho, T.C. Improving the Path to Obtain Spectroscopic Parameters for the PI3K—(Platinum Complex) System: Theoretical Evidences for Using ¹⁹⁵Pt NMR as a Probe. Magnetochemistry 2023, 9, 89. [Google Scholar] [CrossRef]
Horiuchi, S.; Umakoshi, K. Recent advances in pyrazolato-bridged homo- and heterometallic polynuclear platinum and palladium complexes. Coord. Chem. Rev. 2023, 476, 214924. [Google Scholar] [CrossRef]
Melník, M.; Mikuš, P. Organomonophosphines in PtP²Cl² Derivatives: Structural Aspects. Rev. Inorg. Chem. 2015, 35, 179–189. [Google Scholar] [CrossRef]
Melník, M.; Mikuš, P. Organodiphosphines in PtP₂X₂ (X = As, Ge or Te) Derivatives—Structural Aspects. Main. Group. Chem. 2020, 43, 132–137. [Google Scholar] [CrossRef]
Melník, M.; Mikuš, P. Distortion Isomers of Cis-PtP₂X₂ and Cis-PtP₂XY Derivatives—Structural Aspects. Rev. Inorg. Chem. 2020, 40, 153–165. [Google Scholar] [CrossRef]
Albrecht, M.; van Koten, G. Platinum Group Organometallics Based on “Pincer” Complexes: Sensors, Switches, and Catalysts. Angew. Chem. Int. Ed. 2001, 40, 3750. [Google Scholar] [CrossRef]
van der Boom, M.E.; Milstein, D. Cyclometalated Phosphine-Based Pincer Complexes: Mechanistic Insight in Catalysis, Coordination, and Bond Activation. Chem. Rev. 2003, 103, 1759. [Google Scholar] [CrossRef]
Rybtchinski, B.; Milstein, D. Metal Insertion into C−C Bonds in Solution. Angew. Chem. Int. Ed. 1999, 38, 870. [Google Scholar] [CrossRef]
Singleton, J.T. The Uses of Pincer Complexes in Organic Synthesis. Tetrahedron 2003, 59, 1837–1857. [Google Scholar] [CrossRef]
Vigalok, A.; Milstein, D. Advances in metal chemistry of quinonoid compounds: New types of interactions between metals and aromatics. Acc. Chem. Res. 2001, 34, 798–807. [Google Scholar] [CrossRef] [PubMed]
Milstein, D. Challenging metal-based transformations. From single-bond activation to catalysis and metallaquinonoids. Pure Appl. Chem. 2003, 75, 445–460. [Google Scholar] [CrossRef]
Jensen, C.M. Iridium PCP pincer complexes: Highly active and robust catalysts for novel homogeneous aliphatic dehydrogenations. Chem. Commun. 1999, 2443–2449. [Google Scholar] [CrossRef]
Gandelman, M.; Konstantinovski, L.; Rozenberg, H.; Milstein, D. Interplay between solvent and counteranion stabilization of highly unsaturated rhodium(III) complexes: Facile unsaturation-induced dearomatization. Chem. Eur. J. 2003, 9, 2595–2602. [Google Scholar] [CrossRef]
Melník, M.; Mikuš, P. Tetradentate organophosphines in Pt(η⁴–A₄L) (A = P₄, P₃Si), P₂X₂ (X₂ = N₂, S₂, C₂), (PX₃) (X₃ = N₃, N₂O): Structural aspects. Main Group Met. Chem. 2021, 44, 270–280. [Google Scholar] [CrossRef]
Melník, M.; Mikuš, P. Heterotridentate organophosphines in Pt(κ3–P1C1P2)(X), (X=H, OL, NL, CL, Cl, Br or I) and Pt(κ3–P1P2C1)(Cl) derivatives structural aspects. J. Mol. Struct. 2023, 1276, 134768. [Google Scholar] [CrossRef]
Lenero, K.Q.A.; Guari, Y.; Kamer, P.C.J.; van Leeuwen, P.W.N.M.; Donnadiere, B.; Sabo-Etienne, S.; Chaudret, B.; Lutz, M.; Spek, A.L. Heterolytic activation of dihydrogen by platinum and palladium complexes. Dalton Trans. 2013, 42, 6495–6512. [Google Scholar] [CrossRef]
Liang, L.C.; Lin, J.M.; Lee, W.Y. Benzene C–H Activation by Platinum(Ii) Complexes of Bis(2-Diphenylphosphinophenyl)Amide. Chem. Commun. 2005, 19, 2462–2464. [Google Scholar] [CrossRef]
Feller, M.; Ben-Ari, E.; Iron, M.A.; Diskin-Posner, Y.; Leitus, G.; Shimon, L.J.W.; Konstantinovski, L.; Milstein, D. Cationic, Neutral, and Anionic PNP Pd II and Pt II Complexes: Dearomatization by Deprotonation and Double-Deprotonation of Pincer Systems. Inorg. Chem. 2010, 49, 1615–1625. [Google Scholar] [CrossRef] [PubMed]
Carlisle, S.; Matta, A.; Valles, H.; Bracken, J.B.; Miranda, M.; Yoo, J.; Hahn, C. Addition to Alkynes Promoted by a Dicationic Platinum(II) Complex. Organometallics 2011, 30, 6446–6457. [Google Scholar] [CrossRef]
Hahn, C. Structural Investigations of Platinum(II) Styrene and Styryl Complexes and Mechanistic Study of Vinylic Deprotonation. Organometallics 2010, 29, 1331–1338. [Google Scholar] [CrossRef]
DeMott, J.C.; Bhuvanesh, N.; Ozerov, O.V. Frustrated Lewis Pair-like Splitting of Aromatic C–H Bonds and Abstraction of Halogen Atoms by a Cationic [(FPNP)Pt]⁺. Species. Chem. Sci. 2013, 4, 642–649. [Google Scholar] [CrossRef]
Cucciolito, M.E.; D’Amora, A.; Tuzi, A.; Vitagliano, A. Catalytic Hydroarylation of Olefins Promoted by Dicationic Platinum(II) and Palladium(II) Complexes. The Interplay of C−C Bond Formation and M−C Bond Cleavage. Organometallics 2007, 26, 5216–5223. [Google Scholar] [CrossRef]
Lansing, R.B.; Goldberg, K.I.; Kemp, R.A. Unsymmetrical RPNPR′ Pincer Ligands and Their Group 10 Complexes. Dalton Trans. 2011, 40, 8950–8958. [Google Scholar] [CrossRef]
Sacco, A.; Vasapollo, G.; Nobile, C.F.; Piergiovanni, A.; Pellinghelli, M.A.; Lanfranchi, M. Syntheses and Structures of 2-Diphenylphosphinomethylenide-6-Diphenylphosphinomethylenepyridine Complexes of Palladium(II) and Platinum(II); Crystal Structures of [PtCl2-(CHPPH₂)-6-(CH₂PPh₂)Pyridine] and [Pd(COOMe)₂-(CHPPh₂)-6-(CH₂PPh₂)Pyridine]. J. Organomet. Chem. 1988, 356, 397–409. [Google Scholar] [CrossRef]
Takeuchi, K.; Taguchi, H.; Tanigawa, I.; Tsujimoto, S.; Matsuo, T.; Tanaka, H.; Yoshizawa, I.K.; Ozawa, F. A Square-Planar Complex of Platinum(0). Angew. Chem. Int. Ed. Engl. 2016, 55, 15347–15350. [Google Scholar] [CrossRef]
Taguchi, H.; Chang, Y.H.; Takeuchi, K.; Ozawa, F. Catalytic Synthesis of an Unsymmetrical PNP-Pincer-Type Phosphaalkene Ligand. Organometallics 2015, 34, 1589–1596. [Google Scholar] [CrossRef]
Adams, J.J.; Arulsamy, N.; Roddick, D.M. Acceptor Pincer Coordination Chemistry of Platinum: Reactivity Properties of (^CF₃ PCP)Pt(L) + (L = NC₅F₅, C₂H₄). Organometallics 2009, 28, 1148–1157. [Google Scholar] [CrossRef]
Arunachalampillai, A.; Loganathan, N.; Wendt, O.F. Carboxylation of Pincer PCP Platinum Methoxide Complexes under Formation of Metalla Carbonates. Polyhedron 2012, 32, 24–29. [Google Scholar] [CrossRef]
Musa, S.; Shpruhman, A.; Gelman, D. New PC(sp³)P pincer complexes of platinum and palladium. J. Organomet. Chem. 2012, 699, 92–95. [Google Scholar] [CrossRef]
De-Botton, S.; Romm, R.; Bensoussan, G.; Hitrik, M.; Musa, S.; Gelman, D. Coordination Versatility of P-Hydroquinone-Functionalized Dibenzobarrelene-Based PC(Sp³)P Pincer Ligands. Dalton Trans. 2016, 45, 16040–16046. [Google Scholar] [CrossRef] [PubMed]
Jia, Y.X.; Yang, X.Y.; Tay, W.S.; Li, Y.; Pullarkat, S.A.; Xu, K.; Hirao, H.; Leung, P.H. Computational and Carbon-13 NMR Studies of Pt–C Bonds in P–C–P Pincer Complexes. Dalton Trans. 2016, 45, 2095–2101. [Google Scholar] [CrossRef] [PubMed]
Adams, J.J.; Lau, A.; Arulsamy, N.; Roddick, D.M. Synthesis and Platinum Coordination Chemistry of the Perfluoroalkyl Acceptor Pincer Ligand, 1,3-(CH₂P(CF₃)₂)₂C₆H₄. Inorg. Chem. 2007, 46, 11328–11334. [Google Scholar] [CrossRef]
Vuzman, D.; Poverenov, E.; Diskin-Posner, Y.; Leitus, G.; Shimon, L.J.W.; Milstein, D. Reactivity and Stability of Platinum(Ii) Formyl Complexes Based on PCP-Type Ligands. The Significance of Sterics. Dalton Trans. 2007, 48, 5692–5700. [Google Scholar] [CrossRef]
Schwartsburd, L.; Poverenov, E.; Shimon, L.J.W.; Milstein, D. Naphthyl-Based PCP Platinum Complexes. Nucleophilic Activation of Coordinated CO and Synthesis of a Pt(II) Formyl Complex. Organometallics 2007, 26, 2931–2936. [Google Scholar] [CrossRef]
Spek, A.L.; Dani, P.; van Koten, G. Crystal Structure of [Pt{η3-Ph2P(C8H7)PPh2}(η1-C12H19N2)]. Private Communication CCDB, IXICEX (2004). Available online: https://www.ccdc.cam.ac.uk/ (accessed on 28 April 2023).
Hughes, R.P.; Williamson, A.; Incarvito, C.D.; Rheingold, A.L. Synthesis and Molecular Structure of a Perfluoroalkyl Complex of Platinum Containing a PCP Pincer Ligand. Organometallics 2001, 20, 4741–4744. [Google Scholar] [CrossRef]
Albrecht, M.; Dani, P.; Lutz, M.; Spek, A.L.; van Koten, G. Transcyclometalation Processes with Late Transition Metals: C-aRyl−H Bond Activation via Noncovalent C−H···Interactions. J. Am. Chem. Soc. 2000, 122, 11822–11833. [Google Scholar] [CrossRef]
Olsson, D.; Arunachalampillai, A.; Wendt, O.F. Synthesis and Characterisation of PCsp³P Phosphine and Phosphinite Platinum(Ii) Complexes. Cyclometallation and Simple Coordination. Dalton Trans. 2007, 46, 5427–5433. [Google Scholar] [CrossRef]
Poverenov, E.; Leitus, G.; Shimon, L.J.W.; Milstein, D. C-Metalated Diazoalkane Complexes of Platinum Based on PCP- and PCN-Type Ligands. Organometallics 2005, 24, 5937–5944. [Google Scholar] [CrossRef]
Fischer, S.; Wendt, O.F. {2,6-Bis[(Diphenylphosphino)Methyl]phenyl} chloroplatinum(II). Acta Cryst. Sect. E Struct. Rep. Online 2004, 60, m69–m70. [Google Scholar] [CrossRef]
Hu, J.; Xu, H.; Nguyen, M.H.; Yip, J.H.K. Photooxidation of a Platinum-Anthracene Pincer Complex: Formation and Structures of Pt II -Anthrone and -Ketal Complexes. Inorg. Chem. 2009, 48, 9684–9692. [Google Scholar] [CrossRef] [PubMed]
Yang, X.Y.; Tay, W.S.; Li, Y.; Pullarkat, S.A.; Leung, P.H. Versatile Syntheses of Optically Pure PCE Pincer Ligands: Facile Modifications of the Pendant Arms and Ligand Backbones. Organometallics 2015, 34, 1582–1588. [Google Scholar] [CrossRef]
Azerraf, C.; Gelman, D. New Shapes of PC(Sp³)P Pincer Complexes. Organometallics 2009, 28, 6578–6584. [Google Scholar] [CrossRef]
Williams, B.S.; Dani, P.; Lutz, M.; Spek, A.L.; van Koten, G. Development of the First P-Stereogenic PCP Pincer Ligands, Their Metallation by Palladium and Platinum, and Preliminary Catalysis. Helv. Chim. Acta 2001, 84, 3519–3530. [Google Scholar] [CrossRef]
Suess, D.L.M.; Peters, J.C. Late-Metal Diphosphinosulfinyl S(O)P 2 Pincer-Type Complexes. Organometallics 2012, 31, 5213–5222. [Google Scholar] [CrossRef]
Siah, S.Y.; Leung, P.H.; Mok, K.F. Palladium(II) and Platinum(II) Complexes with a Novel P—S(O)—P Tridentate Ligand. Polyhedron 1994, 13, 3253–3255. [Google Scholar] [CrossRef]
Andreasen, L.V.; Hazell, A.; Wernberg, O. [Bis(2-Diphenylphosphinoethyl) Sulfide-κ³P,S,P′](Triphenylphosphine-κP)Platinum(II) Diperchlorate Acetone Solvate. Acta Crystallogr. Sect. C Cryst. Struct. Commun. 2002, 58, m385–m387. [Google Scholar] [CrossRef]
Emslie, D.J.H.; Harrington, L.E.; Jenkins, H.A.; Robertson, C.M.; Britten, J.F. Group 10 Transition-Metal Complexes of an Ambiphilic PSB-Ligand: Investigations into η³(BCC)-Triarylborane Coordination. Organometallics 2008, 27, 5317–5325. [Google Scholar] [CrossRef]
Suh, H.W.; Balcells, D.; Edwards, A.J.; Guard, L.M.; Hazari, N.; Mader, E.A.; Mercado, B.Q.; Repisky, M. Understanding the Solution and Solid-State Structures of Pd and Pt PSiP Pincer-Supported Hydrides. Inorg. Chem. 2015, 54, 11411–11422. [Google Scholar] [CrossRef] [PubMed]
Mitton, S.J.; McDonald, R.; Turculet, L. Synthesis and Characterization of Neutral and Cationic Platinum(II) Complexes Featuring Pincer-like Bis(Phosphino)Silyl Ligands: Si−H and Si−Cl Bond Activation Chemistry. Organometallics 2009, 28, 5122–5136. [Google Scholar] [CrossRef]
Korshin, E.E.; Leitus, G.; Shimon, L.J.W.; Konstantinovski, L.; Milstein, D. Silanol-Based Pincer Pt(II) Complexes: Synthesis, Structure, and Unusual Reactivity. Inorg. Chem. 2008, 47, 7177–7189. [Google Scholar] [CrossRef] [PubMed]
DeMott, J.C.; Gu, W.; McCulloch, B.J.; Herbert, D.E.; Goshert, M.D.; Walensky, J.R.; Zhou, J.; Ozerov, O.V. Silyl–Silylene Interplay in Cationic PSiP Pincer Complexes of Platinum. Organometallics 2015, 34, 3930–3933. [Google Scholar] [CrossRef]
Brost, R.D.; Bruce, G.C.; Joslin, F.L.; Stobart, S.R. Phosphinoalkylsilyl Complexes. 12. Stereochemistry of the Tridentate Bis(Diphenylphosphinopropyl)Silyl (BiPSi) Framework: Complexation That Introduces “Face Discrimination” at Coordinatively Unsaturated Metal Centers. X-Ray Crystal and Molecular Structure. Organometallics 1997, 16, 5669–5680. [Google Scholar] [CrossRef]
Bachechi, F. X-Ray Structural Analysis of NiII, PdII, and PtII Complexes with the Potentially Tridentate Ligand 1,3-Bis(Diphenylphosphinomethyl)Benzene, 1,3-C₆H₄(CH₂PPh₂)₂. Struct. Chem. 2003, 14, 263–269. [Google Scholar] [CrossRef]
Tsay, C.; Mankad, N.P.; Peters, J.C. Four-Coordinate, Trigonal Pyramidal Pt(II) and Pd(II) Complexes. J. Am. Chem. Soc. 2010, 132, 13975–13977. [Google Scholar] [CrossRef]
Takaya, J.; Iwasawa, N. Reaction of Bis(o-Phosphinophenyl)Silane with M(PPh₃)₄(M = Ni, Pd, Pt): Synthesis and Structural Analysis of H²-(Si–H) Metal(0) and Pentacoordinate Silyl Metal(Ii) Hydride Complexes of the Ni Triad Bearing a PSiP-Pincer Ligand. Dalton Trans. 2011, 40, 8814–8821. [Google Scholar] [CrossRef]
Yang, L.; Powell, D.R.; Houser, R.P. Structural Variation in Copper(i) Complexes with Pyridylmethylamide Ligands: Structural Analysis with a New Four-Coordinate Geometry Index, Τ4. Dalton Trans. 2007, 9, 955–964. [Google Scholar] [CrossRef]

Figure 1. Structure of [Pt{η³-Ph₂P(C₁₂H₈N)PPh₂}(py)] [20].

Figure 2. Structure of [Pt{η³-Pri₂P(C₂₀H₁₁)PPrⁱ₂}(OOCCF₃)] [32].

Figure 3. Structure of [Pt{η³-Ph₂P(C₆H₄)S(=O)(C₆H₄)PPh₂}(CH₃)] [49].

Figure 4. Structure of [Pt{η³-Ph₂P(C₆H₄)Si(Me)(C₆H₄)PPh₂}(OEt₂)] [53].

Figure 5. Structure of [Pt{η³-Ph₂P(C₆H₄)Si(Me)(C₆H₄)PPh₂}(PPh₃)] [59].

Table 1. Crystallographic and structural data for Pt{η³–P¹X¹P²}(Y), (X¹ = O¹, N¹), (Y = C²L, N²L, Cl, P³L) complexes ^a.

Complex	Cryst. cl. Space gr. Z	a (Å) b (Å) c (Å)	α (°) β (°) γ (°)	Chromophore (Chelate Rings) τ₄ ^b	Pt-L ^c (Å)	L-Pt-L ^c (˚)	Ref.
[Pt{η³-Ph₂P(C₁₅H₁₂O) PPh₂} {η¹-P³(C₅H₄N) (Ph)₂}].2CF₃SO₃.0.5H₂O (at 150 K)	m C2/c 4	42.762(0) 12.161(0) 23.995(0)	121.60(0)	PtP₂OP (P¹C₂O¹C₂P²) 0.164	P¹,P² 2.302(-,11) O¹ 2.189 P³ 2.239	P^1,2,O¹ 81.6(-,7) ^d P¹,P² 162.2 P^1,2,P³ 98.5(-,1,7) O¹,P³ 174.7(2)	[19]
[Pt{η³-Ph₂P (C₁₂H₈N). PPh₂-P¹,N¹,P²}(py)]. CF₃SO₃.toluene	m P2₁/n 4	15.114(0) 17.695(0) 16.901(0)	105.98(0)	PtP₂NN (P¹C₂N¹C₂P²) 0.125	P¹ 2.294 P² 2.273 N¹ 2.024 py, N² 2.056	P^1,2,N¹ 83.3(-,7) ^d P¹,P² 166.6 P^1,2,N² 96.1(-,3.0) N¹,N² 175.6	[20]
[Pt{η³-Ph₂P(C₂H₈N)PPh₂-P¹,N¹,P²}(CH₃)]	or Fdd2 4	9.961(0) 18.601(0) 32.725(0)		PtP₂NC (P¹C₂N¹C₂P²) 0.110	P¹ 2.274 P² 2.274 N¹ 2.093 C 2.110	P^1,2,N¹ 82.3 ^d P¹,P² 164.6 P^1,2,C 97.7 N¹,C 180.0	[20]
[Pt{η³-Bu^t₂P(C₇H₇N) PBu^t₂-P¹,N¹,P²} (CH₃)]Cl.CHCl₃ (at 100 K)	tr P $\bar{1}$ 2	14.569(0) 15.447(0) 16.237(0)	114.73(0) 99.12(0) 96.40(0)	PtP₂NC (P¹C₂N¹C₂P²) 0.128	P¹ 2.286 P² 2.301 N¹ 2.108 C 2.057	P^1,2,N¹ 84.0 ^d P¹,P² 164.4 P^1,2,C 96.1(-,1) N¹,C 177.5	[21]
[Pt{η³-Bu^t₂P(C₇H₇N)PBu^t₂-P¹,N¹,P²} (CH₃)]Cl.CHCl₃ (at 100 K)	m P2₁/c 8	10.976(2) 15.479(3) 30.094(3)	90.71(3)	PtP₂NC (P¹C₂N¹C₂P²) 0.120	P¹ 2.295 P² 2.282 N¹ 2.089 C 2.105	P^1,2,N¹ 83.2(-,4) ^d P¹,P² 164.6 N¹,N² 96.6(-,5) N¹,C 178.3	[21]
[Pt{η³-Ph₂P(C₇H₇N) PPh₂-P¹,N¹,P²}{C(=O) Et}].BF₄.0.5CH₂Cl₂ (at 100 K)	m P2₁/n 4	18.173(3) 9.960(1) 21.092(4)	114.94(0)	PtP₂NC (P¹C₂N¹C₂P²) 0.130	P¹ 2.279 P² 2.284 N¹ 2.131 C 2.001	P^1,2,N¹ 81.8(-,4) ^d P¹,P² 163.6 P^1,2,C 98.1(-,1.8) N¹,C 178.0	[22]
[Pt{η³-Ph₂P(C₇H₇N) PPh₂-P¹,N¹,P²} (CH₂CHO)].BF₄ (at 110 K)	tr P $\bar{1}$ 2	9.198(1) 10.688(1) 16.421(1)	99.77(0) 100.04(0) 97.95(0)	PtP₂NC (P¹C₂N¹C₂P²) 0.112	P¹ 2.269 P² 2.303 N¹ 2.112 C 2.132	P^1,2,N¹ 83.0(-,2) ^d P¹,P² 165.9 P^1,2,C 97.0(-,1.7) N¹,C 178.1	[22]
[Pt{η³-Ph₂P(C₇H₇N)PPh₂-P¹,N¹,P²} (CH = CHPh)].BF₄	tr P $\bar{1}$ 2	12.534(8) 17.101(8) 17.919(8)	70.04(0) 82.64(0) 78.66(0)	PtP₂NC (P¹C₂N¹C₂P²) 0.135	P¹ 2.289 P² 2.309 N¹ 2.125 C 2.005	P^1,2,N¹ 82.3(-,6) ^d P¹,P² 164.3 P^1,2,C 97.6(-,1.2) N¹,C 176.6	[23]
[Pt{η³-Prⁱ₂P(C₁₂H₇F₂N)PPrⁱ₂-P¹,N¹,P²} (C₆H₄F)].B(C₆F₄)₄ (at 110 K)	m P2₁/c 4	15.495(2) 18.673(3) 22.444(2)	125.95(0)	PtP₂NC (P¹C₂N¹C₂P²) 0.171	P¹ 2.286 P² 2.272 N¹ 2.126 C 2.015	P^1,2,N¹ 83.0(-,1.2) P¹,P² 163.4 P^1,2,C 96.5(-,2.0) N¹,C 172.3	[24]
[Pt{η³-Prⁱ₂P(C₁₂H₇F₂N)PPrⁱ₂-P¹,N¹,P²} (p-tol)].B(C₆F₅)₄ (at 110 K)	m P2₁/n 4	15.655(1) 18.868(1) 18.242(1)	98.76(0)	PtP₂NC (P¹C₂N¹C₂P²) 0.225	P¹ 2.288 P² 2.270 N¹ 2.183 C 2.070	P^1,2,N¹ 83.9(-,8) P¹,P² 161.4 P^1,2,C 97.4(-,3.5) N¹,C 166.8	[24]
[Pt{η³-Ph₂P(C₇H₇N)PPh₂-P¹,N¹,P²} (C₁₁H₁₅O₃)].BF₄	m P2₁/c 4	18.286(2) 11.617(3) 20.683(1)	114.68(1)	PtP₂NC (P¹C₂N¹C₂P²) 0.130	P¹ 2.263 P² 2.282 N¹ 2.097 C 2.157	P^1,2,N¹ 83.0(-,9) P¹,P² 164.9 P^1,2,C 97.1(-,1.6) N¹,C 176.6	[25]
[Pt{η³-Ph₂P(C₁₂H₈N)PPh₂}(Cl)].5C₆H₆	m P2₁/n 4	17.378(0) 12.705(0) 25.555(0)	104.58(0)	PtP₂NCl (P¹C₂N¹C₂P²) 0.107	P^1,2 2.277(-,7) N¹ 2.024 Cl 2.318	P^1,2,N¹ 83.7(-,1) P¹,P² 167.3 P^1,2,Cl 96.3(-,1.9) N¹,Cl 177.5	[20]
[Pt{η³-Bu^t₂P(C₇H₆N)PBu^t₂}(Cl)] (at 120 K)	or Pna2₁ 4	22.499(0) 8.107(0) 14.161(0)		PtP₂NCl (P¹C₂N¹C₂P²) 0.102	P^1,2 2.296(-,15) N¹ 2.021 Cl 2.333	P^1,2,N¹ 84.6(-,3) P¹,P² 169.2 P^1,2,Cl 95.3(-,4) N¹,Cl 176.5	[21]
[Pt{η³-Bu^t₂P(C₇H₇N)PBu^t₂}(Cl)]Cl	trg P3 6	18.631(3) 14.821(3)		PtP₂NCl (P¹C₂N¹C₂P²) 0.092	P^1,2 2.302(-,1) N¹ 2.030 Cl 2.307	P^1,2,N¹ 84.2(-,3) P¹,P² 168.2 P^1,2,Cl 95.8(-,5) N¹,Cl 178.9	[21]
[Pt{η³-Prⁱ₂P(C₁₂H₆F₂N)PPrⁱ₂} (Cl)].CHB₁₁Cl₁₁ (at 110 K)	m P2₁/c 4	19.446(20) 15.820(18) 15.256(15)	107.78(1)	PtP₂NCl (P¹C₂N¹C₂P²) 0.151	P¹ 2.285 P² 2.304 N¹ 1.987 Cl 2.297	P^1,2,N¹ 84.2(-,6) P¹,P² 166.7 P^1,2,Cl 95.8(-,1.9) N¹,Cl 171.9	[24]
[Pt{η³-Ph₂P(C₁₄H₁₂N)PPrⁱ₂}(Cl)].0.5C₆H₆ (at 183 K)	m P2₁/c 4	9.702(0) 11.526(0) 28.499(1)	100.73(0)	PtP₂NCl (P¹C₂N¹C₂P²) 0.120	P^1,2 2.278(-,5) N¹ 2.028 Cl 2.321	P^1,2,N¹ 83.2(-,1.2) ^d P¹,P² 164.0 P^1,2,Cl 96.7(-,1.2) N¹,Cl 179.2	[26]
[Pt{η³-Ph₂P(C₁₄H₁₂N) P(cy)₂} (Cl)].C₆H₆ (at 183 K)	tr P $\bar{1}$ 2	11.322(0) 11.735(0) 15.501(0)	93.81(0) 110.18(0) 93.00(0)	PtP₂NCl (P¹C₂N¹C₂P²) 0.135	P^1,2 2.282(-,9) N¹ 2.047 Cl 2.322	P^1,2,N¹ 82.9(-,1) P¹,P² 164.8 P^1,2,Cl 97.2(-,2.0) N¹,Cl 176.1	[26]
[Pt{η³-Ph₂P(CH₂)(C₅H₄N)(CH₂)Ph₂P-P¹,N¹,P²}(Cl)]	m P2₁/n 4	15.915(5) 19.337(8) 8.861(6)	98.94(2)	PtP₂NCl (P¹C₂N¹C₂P²) 0.089	P^1,2 2.285(3,1) N¹ 2.2008(7) Cl 2.312(3)	P^1,2,N¹ 84.6(2,4) ^d P¹,P² 169.0(2) P^1,2,Cl 95.5(1,9) N¹,Cl 178.5(2)	[27]
[Pt{η³-(η¹-C₂₄H₄₄)P(C₇H₆N)P(η¹-C₂₄H₄₄)}(PPh₃)].2CH₂Cl₂ (at 103 K)	tr P $\bar{1}$ 2	13.341(2) 18.981(4) 30.668(6)	93.86(0) 90.89(0) 98.03 (0)	PtP₂NP (P¹C₂N¹C₂P²) 0.199	P^1,2 2.317(-,8) N¹ 2.082(3) P₃ 2.270	P^1,2,N¹ 80.9(-,6) ^d P¹,P² 158.7 P^1,2,P³ 98.3(-,2.0) N¹, P³ 173.0	[28]
[Pt{η³-(η²-C₁₈H₂₈)P(C₇H₆N)P(η¹-C₁₈H₂₉)}(Pcy₃)] (at 103 K)	m P2₁/c 4	17.281(2) 11.881(1) 28.514(4)	104.32(0)	PtP₂NP (P¹C₂N¹C₂P²) 0.209	P¹ 2.326 P² 2.389 N¹ 2.073 P₃ 2.284	P^1,2,N¹ 82.7(-,1.1) ^d P²,N¹ 162.9 P¹,P¹98.0(-,5.8) N¹, P³ 167.5	[29]

Footnotes: a—Where more than one chemically equivalent distance or angle is present, the mean value is tabulated. The first number in parentheses is e.s.d., and the second is the maximum deviation from the mean. b—The parameters, Ʈ₄, were calculated: Ʈ₄ = 360 − (α + β)/141, where β and α are the two largest angles and assume the values of 0 and 1 for the perfect square planar and perfect tetrahedral geometries, respectively. c—The chemical identity of the coordinated atom or ligand is specified in these columns. d—The five-membered metallocyclic ring.

Table 2. Crystallographic and structural data for Pt{η³-P¹C¹P²}(Y), (Y = O²L, N²L, CL, Cl, Br) complexes ^a.

Complex	Cryst. cl. Space gr. Z	a (Å) b (Å) c (Å)	α (°) β (°) γ (°)	Chromophore (Chelate Rings) τ₄ ^b	Pt-L ^c (Å)	L-Pt-L ^c (°)	Ref.
[Pt{η³-(CF₃)₂P(C₈H₇)P(CF₃)₂}. (H₂O)]SbF₆ (at 150 K)	m C2/c 4	41.924(0) 10.457(0) 22.512(0)	110.54(0)	PtP₂CO (P¹C₂C¹C₂P²) 0.143	P^1,2 2.245 C¹ 1.995 H₂O 2.156	P^1,2,C¹ 81.7(-,2) ^d P¹,P² 163.3 P^1,2,O 98.3(-,3.9) C¹,O 176.3	[30]
[Pt{η³-Ph₂P(C₈H₇) PPh₂}(H₂O)]CF₃SO₃ (at 165 K)	tr Pī 2	9.644(1) 13.885(1) 14.012(3)	119.08(1) 93.43(1) 104.59(1)	PtP₂CO (P¹C₂C¹C₂P²) 0.146	P^1,2 2.295(-,3) C¹ 1.995 H₂O 2.156	P^1,2,C¹ 82.0(-,6) ^d P¹,P² 163.7 P^1,2,O 98.1(-,2.7) C¹,O 176.6	[31]
[Pt{η³-Ph₂P(C₈H₇)PPh₂} (OMe)].0.5C₆H₆	tr Pī 2	8.824(2) 12.517(1) 14.712(2)	91.94(1) 104.96(1) 104.20(1)	PtP₂CO (P¹C₂C¹C₂P²) 0.120	P^1,2 2.266(-,4) C¹ 2.053 MeO 2.086	P^1,2,C¹ 83.7(-,7) ^d P¹,P² 166.6 P^1,2,O 98.8(-,6.8) C¹,O 176.5	[31]
[Pt{(η^3-Prⁱ₂)P(C₂₀H₁₁) P(Prⁱ₂)}(OOCCF₃)] (at 173 K)	or Fdd2 4	29.241(1) 39.275(2) 11.361(0)		PtP₂CO (P¹C₂C¹C₂P²) 0.181	P^1,2 2.289(-,1) C¹ 2.045 O 2.139	P^1,2,C¹ 85.8(-,1) ^d P¹,P² 157.0 P^1,2,O 94.2(-,2.5) C¹,O 177.4	[32]
[Pt{η³-(CF₃)₂P(C₈H₇)P (CF₃)₂}(NC₅F₅)]B(C₆F₅)₄ (at 150 K)	m P2₁/c 4	13.932(1) 17.137(2) 19.213(0)	96.29(0)	PtP₂CN (P¹C₂C¹C₂P²) 0.138	P^1,2 2.242(-,2) C¹ 2.030 N 2.173	P^1,2,C¹ 80.6(-,1) ^d P¹,P² 161.3 P^1,2,N 99.3(-,5) C¹,N 179.2	[30]
[Pt{η³-Ph₂P(C₂₀H₁₃O₄)PPh₂}. (N≡CCH₃)]BF₄ (at 173 K)	or Pca21 6	21.587(3) 8.904(1) 21.327(3)		PtP₂CN (P¹C₂C¹C₂P²) 0.191	P^1,2 2.303(-,1) C¹ 1.892 N 2.088	P^1,2,C¹ 85.9(-,1.9) ^d P¹,P² 156.4 P^1,2,N 93.5 C¹,N 176.8	[32]
[Pt{η³-Ph₂P(C₂₀H₁₁O₂)PPh₂}. (NC₅H₅)]Cl.(NC₅H₅)₃	m P2₁/c 4	12.892(6) 15.613(8) 26.900(10)	101.48(1)	PtP₂CN (P¹C₂C¹C₂P²) 0.138	P^1,2 2.275(-,2) C¹ 2.021 N 2.111	P^1,2,C¹ 81.0 ^d P¹,P² 162.0 P^1,2,N 98.8 C¹,N 178.5	[33]
[Pt{η³-Ph₂P(C₂₀H₁₁O₂)PPh₂}. (N≡CCH₃)]BF₄.CH₂Cl₂ (at 173 K)	m P2₁/c 4	14.711(1) 15.920(1) 17.987(1)	92.15(0)	PtP₂CN (P¹C₂C¹C₂P²) 0.202	P^1,2 2.293(-,5) C¹ 2.062 N 2.056	P^1,2,C¹ 85.7(-,3) ^d P¹,P² 157.4 P^1,2,N 97.3(-,3) C¹,N 174.0	[33]
[Pt{η³-Ph₂P(C₂₄H₁₉O₂)PPh₂}(CN)] (at 103 K)	tg P2₁2₁2₁ 4	9.492(0) 9.492 (0) 13.030(1)		PtP₂C₂ (P¹C₂C¹C₂P²) 0.140	P^1,2 2.286 C¹ 2.029 NC 2.062	P^1,2,C¹ 80.1 ^d P¹,P² 160.1 P^1,2,C 99.2 C¹,C 180.0	[34]
[Pt{η³-(CF₃)₂P(C₈H₇)P. (CF₃)₂}(CO)]SbF₆	tr Pī 2	11.770(1) 13.950(1) 14.529(1)	91.31(0) 100.81(0) 91.90(0)	PtP₂C₂ (P¹C₂C¹C₂P²) 0.125	P^1,2 2.256 C¹ 1.969 OC 2.053	P^1,2,C¹ 81.6(-,3) ^d P¹,P² 163.4 P^1,2,C 98.3(-,3) C¹,C 179.0	[35]
[Pt{η³-(CF₃)₂P(C₈H₇)P. (CF₃)₂}(CH₃)]	m P2₁/c 8	14.732(0) 16.189(0) 17.737(0)	113.42(3)	PtP₂C₂ (P¹C₂C¹C₂P²) 0.153	P^1,2 2.203(-,2) C¹ 2.089 H₃C 2.148	P^1,2,C¹ 81.0(-,5) ^d P¹,P² 161.0 P^1,2,C 98.9(-,4) C¹,C 177.3	[35]
[Pt{η³-Prⁱ₂P(C₈H₇)PPrⁱ₂}(CO)]. CF₃SO₃0.5C₆H₆ (at 120 K)	m P2₁/c 4	13.430(3) 15.667(3) 15.472(3)	112.73(3)	PtP₂C₂ (P¹C₂C¹C₂P²) 0.117	P^1,2 2.305(-,2) C¹ 2.048 C 2.053	P^1,2,C¹ 82.7(-,5) ^d P¹,P² 165.2 P^1,2,C 97.3(-,9) C¹,C 178.2	[36]
[Pt{η³-Bu^t₂P(C₈H₇)PBu^t₂}(η¹-CHOMe)].CF₃SO₃.thf (at 120 K)	m P2₁/c 4	15.824(0) 11.375(0) 20.093(0)	97.46(0)	PtP₂C₂ (P¹C₂C¹C₂P²) 0.123	P^1,2 2.302(-,1) C¹ 2.081 C 1.986	P^1,2,C¹ 81.9(-,3) ^d P¹,P² 163.5 P^1,2,C 98.0(-,1.1) C¹,C 179.2	[34]
[Pt{η³-Bu^t₂P(C₁₂H₉)PBu^t₂} (CO)]BF₄ (at 120 K)	or Pna2₁ 8	12.097(2) 13.150(3) 38.514(8)		PtP₂C₂ (P¹C₂C¹C₂P²) 0.102	P^1,2 2.311(-,4) C¹ 2.074 OC 1.903	P^1,2,C¹ 83.1(-,1) ^d P¹,P² 166.3 P^1,2,C 96.8(-,2) C¹,C 179.3	[37]
[Pt{η³-Ph₂P(C₈H₇)PPh₂}(η¹-C₁₂H₁₉N₂)] (at 150 K)	m P2₁/c 4	17.576(3) 12.436(2) 18.593(5)	114.34(1)	PtP₂C₂ (P¹C₂C¹C₂P²) 0.146	P^1,2 2.269(-,2) C¹ 2.142 C 2.091	P^1,2,C¹ 81.0(-,2) ^d P¹,P² 162.0 P^1,2,C 99.0(-,3.1) C¹,C 177.5	[38]
[Pt{η³-Ph₂P(C₈H₇)PPh₂}(η¹-C₃F₇)] (at 150 K)	m P2₁/c 4	10.192(3) 18.106(8) 17.018(3)	91.01(1)	PtP₂C₂ (P¹C₂C¹C₂P²) 0.143	P^1,2 2.279(-,2) C¹ 2.072 C 2.186	P^1,2,C¹ 81.4(-,2) ^d P¹,P² 162.8 P^1,2,C 98.4(-,5) C¹,C 177.0	[39]
[Pt{η³-Ph₂P(C₈H₇)PPh₂} (η¹-C₁₂H₂₁N₂)]2BF₄ (at 150 K)	m C2 2	12.887(0) 15.901(0) 12.177(0)	121.54(0)	PtP₂C₂ (P¹C₂C¹C₂P²) 0.133	P^1,2 2.275 C¹ 2.084 C 2.096	P^1,2,C¹ 80.6 ^d P¹,P² 161.2 P^1,2,C 99.4 C¹,C 180.0	[40]
[Pt{η³-Ph₂P (C₂₀H₁₁O_2P)Ph₂}Cl]. (CH₃CN)₄ (at 150 K)	tr Pī 2	12.485(1) 14.669(2) 15.038(2)	118.03(0) 106.22 (0) 90.30(0)	PtP₂CCl (P¹C₂C¹C₂P²) 0.232	P^1,2 2.265 C¹ 2.086 Cl 2.394	P^1,2,C¹ 85.4(-,3) ^d P¹, P² 155.4 P^1,2,Cl 96.2(-,6) C¹,Cl 172.0	[33]
[Pt{η³-Ph₂P(C₂₄H₁₉O₂)PPh₂}Cl] (at 103 K)	m P2₁ 4	11.798(3) 26.540(2) 12.725(1)	96.64(0)	PtP₂CCl (P¹C₂C¹C₂P²) 0.138	P^1,2 2.276(-,1) C¹ 2.022 Cl 2.388	P^1,2,C¹ 82.7(-,1.0) ^d P¹, P² 163.9 P^1,2,Cl 97.4(-,4) C¹,Cl 176.4	[34]
[Pt{η³-(CF₃)₂P(C₈H₇)P (CF₃)₂}Cl]1.5(C₆H₆) (at 173 K)	m P2₁/c 4	10.111(0) 19.270(0) 13.082(0)	102.86(0)	PtP₂CCl (P¹C₂C¹C₂P²) 0.156	P^1,2 2.233(-,5) C¹ 2.037 Cl 2.370	P^1,2,C¹ 80.9(-,3) ^d P¹, P² 161.0 P^1,2,Cl 99.2(-,5) C¹,Cl 176.9	[35]
[Pt{η³-Bu^t₂P(C₈H₇)PBu^t₂}Cl] (at 120 K)	or P2₁2₁2₁ 8	12.965(3) 13.853(3) 14.642(3)		PtP₂CCl (P¹C₂C¹C₂P²) 0.094	P^1,2 2.288(-,3) C¹ 2.017 Cl 2.407	P^1,2,C¹ 83.7(-,1) ^d P¹, P² 167.3 P^1,2,Cl 96.3(-,64) C¹,Cl 179.2	[36]
[Pt{η³-Bu^t₂P(C₁₂H₉)PBu^t₂}Cl] (at 120 K)	m P2₁/n 4	16.195(3) 10.440(2) 17.588(4)	109.21(3)	PtP₂CCl (P¹C₂C¹C₂P²) 0.097	P^1,2 2.287(-,6) C¹ 2.016 Cl 2.431	P^1,2,C¹ 83.9(-,4) ^d P¹, P² 167.7 P^1,2,Cl 96.1(-,6) C¹,Cl 178.7	[37]
[Pt{η³-Bu^t₂P(C₈H₇)PBu^t₂}Cl]	m P2₁/n 4	12.018(0) 14.803(0) 15.728(0)	100.79(0)	PtP₂CCl (P¹C₂C¹C₂P²) 0.120	P^1,2 2.305(-,3) C¹ 2.065 Cl 2.434	P^1,2,C¹ 83.8(-,5) ^d P¹, P² 167.3 P^1,2,Cl 96.1(-,1) C¹,Cl 175.6	[41]
Pt{η³-Prⁱ₂P(C₈H₇)PPrⁱ₂}Cl] (at 120 K)	tr Pī 2	11.148(2) 13.935(3) 14.683(3)	78.16(3) 82.35(3) 89.33(3)	PtP₂CCl (P¹C₂C¹C₂P²) 0.105	P^1,2 2.279(-,4) C¹ 2.006 Cl 2.436	P^1,2,C¹ 83.6(-,2) ^d P¹, P² 167.4 P^1,2,Cl 96.1(-,1) C¹,Cl 177.7	[42]
[Pt{η³-Ph₂P(C₈H₇)PPh₂}Cl]	m P2₁/n 4	10.290(2) 16.117(3) 15.173(3)	105.47(3)	PtP₂CCl (P¹C₂C¹C₂P²) 0.130	P^1,2 2.277(-,2) C¹ 2.002 Cl 2.383	P^1,2,C¹ 81.6(-,6) ^d P¹,P² 163.1 P^1,2,Cl 98.4(-,1.1) C¹,Cl 178.5	[43]
[Pt{η³-Ph₂P(C₁₄H₇)PPh₂}Cl]. CH₃CN (at 223 K)	m P2₁/c 4	12.773(0) 17.780(0) 14.72448(0)	96.54(0)	PtP₂CCl (P¹C₂C¹C₂P²) 0.107	P^1,2 2.268(-,2) C¹ 1.991 Cl 2.391	P^1,2,C¹ 83.7(-,1) ^d P¹,P² 167.3 P^1,2,Cl 96.2(-,1.7) C¹,Cl 177.5	[44]
[Pt{η³-Ph₂P(C₁₃H₇O₂)PPh₂} Cl].CH₃CN (at 223 K)	or Pbca 8	18.768(0) 16.966(0) 21.649(0)		PtP₂CCl (P¹C₂C¹C₂P²) 0.138	P^1,2 2.266(-,1) C¹ 2.050 Cl 2.397	P^1,2,C¹ 84.6(-,7) ^d P¹,P² 166.3 P^1,2,Cl 95.8(-,2) C¹,Cl 174.3	[44]
[Pt{η³-Ph₂P(C₁₈H₁₉O₈) PPh₂}Cl]CH₂Cl₂ (at 103 K)	or P2₁2₁2₁ 8	10.432(1) 17.092(2) 24.423(3)		PtP₂CCl (P¹C₂C¹C₂P²) 0.163	P^1,2 2.277(-,5) C¹ 2.006 Cl 2.385	P^1,2,C¹ 81.0(-,1) ^d P¹,P² 162.0 P^1,2,Cl 99.0(-,5) C¹,Cl 174.7	[45]
Pt{η³-Prⁱ₂P(C₂₀H₁₁)PPrⁱ₂}Cl]. (CH₃CN)₂	m P2₁/n 4	14.622(0) 15.048(1) 15.642(1)	96.24(0)	PtP₂CCl (P¹C₂C¹C₂P²) 0.171	P^1,2 2.284(-,1) C¹ 2.064 Cl 2.392	P^1,2,C¹ 86.0(-,2) ^d P¹,P² 156.2 P^1,2,Cl 94.0(-,2) C¹,Cl 179.53	[46]
[Pt{η³-Ph₂P(C₈H₇)PPh₂}Br]	m P2₁/n 4	10.127(2) 14.776(2) 19.023(3)	91.01(1)	PtP₂CBr (P¹C₂C¹C₂P²) _0.138	P^1,2 2.272(-,14) C¹ 2.023 Br 2.468	P^1,2,C¹ 82.4(-,1) ^d P¹,P² 164.8 P^1,2,Br 97.7(-,6) C¹,Br 175.8	[47]
[Pt{η³-Bu^t₂P(C₆H₅N₂)PBu^t₂}(Br)] (at 150 K)	m C2 4	15.517(0) 13.055(0) 15.383(0)	118.78(0)	PtP₂CBr (P¹C₂C¹C₂P²) 0.140	P¹ 2.290 P² 2.030 Br 2.466	P^1,2,C¹ 82.5 ^d P¹,P² 165.0 P^1,2,Br 97.5 C¹,Br 175.2	[40]

Footnotes: a—Where more than one chemically equivalent distance or angle is present, the mean value is tabulated. The first number in parentheses is e.s.d., and the second is the maximum deviation from the mean. b—The parameters, τ₄, were calculated τ₄ = 360 − (α + β)/141, where β and α are the two largest angles and assume the values of 0 and 1 for the perfect square planar and perfect tetrahedral geometries, respectively. c—The chemical identity of the coordinated atom or ligand is specified in these columns. d—Five-membered metallocyclic ring.

Table 3. Crystallographic and structural data for Pt(η³–P¹X¹P²)(Y), (X¹ = S¹ or Si¹), (Y = C²L,Cl,P³L,I,H,O²L) complexes ^a.

Complex	Cryst. cl. Space gr. Z	a (Å) b (Å) c (Å)	α (°) β (°) γ (°)	Chromophore (Chelate Rings) τ₄ ^b	Pt-L ^c (Å)	L-Pt-L ^c (˚)	Ref.
[Pt{η³-Ph₂P(C₆H₄) S(=O)(C₆H₄)PPh₂} (CH₃)]PF₆.CH₃CN (at 100 K)	m P2₁/n 4	8.936(2) 16.722(4) 25.078(6)	95.72(1)	PtP₂SC (P¹C₂S¹C₂P²) 0.102	P^1,2 2.273(-,3) S¹ 2.268 H₃C 2.093	P^1,2,S¹ 86.6(-,1) ^d P¹,P² 167.0 P^1,2,C 93.2(-,3) S¹,C 178.2	[48]
[Pt{η³-Ph₂P(C₆H₄)S(=O)(C₆H₄)PPh₂}(Cl)].PF₆.CH₃CN	m P2₁/c 4	13.360(0) 15.308(0) 18.787(0)	106.11(0)	PtP₂SCl (P¹C₂S¹C₂P²) 0.140	P^1,2 2.307 S¹ 2.192 Cl 2.316	P^1,2,S 84.6 P¹,P² 162.7 P^1,2,Cl 94.8 S¹,Cl 177.6	[48]
[Pt{η³-Ph₂P(CH₂)₂ S(=O)(CH₂)₂PPh₂}(Cl)].ClO₄	tr P $\bar{1}$ 2	9.460(2) 12.079(3) 13.834(3)	93.53(2) 103.85(2) 104.22(2)	PtP₂SCl (P¹C₂S¹C₂P²) 0.135	P 2.319(2,0) S¹ 2.182(2) Cl 2.318(1)	P^1,2,S¹ 85.6 P¹,P² 164.4 P^1,2,Cl 95.8 S¹,Cl 176.6	[49]
[Pt{η³-Ph₂P(C₆H₄) S(=O)(C₆H₄)PPh₂}(PPh₃)].0.5(CH₂Cl₂)(at 100 K)	tr P $\bar{1}$ 2	11.295(5) 11.469(1) 17.269(1)	86.45(1) 88.54(1) 77.08(1)	PtP₂SP (P¹C₂S¹C₂P²) 0.143	P^1,2 2.273(-,3) S¹ 2.313 Ph₃P³ 2.281	P^1,2,S¹ 86.0(-,3) ^d P¹,P² 162.4 P^1,2,P³ 94.7 S¹,P³ 177.5	[48]
[Pt{η³-Ph₂P(CH₂)₂S (CH₂)₂}PPh₂}(PPh₃)].2.ClO₄ Me₂CO (at 120 K)	or Pnma 4	15.698(3) 15.337(3) 19.957(4)		PtP₂SP (P¹C₂S¹C₂P²) 0.143	P^1,2 2.309(-,1) S¹ 2.343 Ph₃P³ 2.289	P^1,2,S¹ 81.3 ^d P¹,P² 161.6 P^1,2,P³ 98.7 S¹,P³ 178.3	[50]
[Pt{η³-Ph₂P(C₂₃H₂₈S)PPh₂}(I)](I).1.74 CH₂Cl₂(at 173 K)	tr P $\bar{1}$ 2	9.845(0) 15.277(0) 17.264(0)	84.94(0) 84.03(0) 89.18(0)	PtP₂Si (P¹C₂S¹C₂P²) 0.120	P^1,2 2.311(-,1) S¹ 2.252 I 2.510	P^1,2,S¹ 84.0(-,3) ^d P¹,P² 165.4 P^1,2,I 96.7 S, I 177.7	[51]
[Pt{η³-cyh₂P(C₆H₄)Si(Me). (C₆H₄)Pcyh₂}(H)].0.5 pentane (at 150 K)	m C2/c 4	24.426(0) 16.300(0) 39.968(3)	105.39(0)	PtP₂SiH (P¹C₂Si¹C₂P²) 0.179	P^1,2 2.254(-,4) Si¹ 2.326 H 1.486	P^1,2,Si¹ 85.3(-,0) ^d P¹, P² 159.5 P^1,2,H 94.7(-,4.7) Si¹, H 175.3	[52]
[Pt{η³-cyh₂P(C₆H₄)Si (Me)(C₆H₄)Pcyh₂}(H)].1.25 pentane (at 93 K)	m C2/c 4	29.595(0) 17.388(0) 33.970(2)	99.64(0)	PtP₂SiH (P¹C₂Si¹C₂P²) 0.158	P^1,2 2.262(0,2) Si¹ 2.336 H 1.527	P^1,2,Si¹ 84.2(-,0) ^d P¹, P² 162.0 P^1,2,H 94.6(-,7) Si¹, H 175.6	[52]
[Pt{η³-Ph₂P(C₆H₄)Si(Me) (C₆H₄)PPh₂}(OEt₂)].{B(C₆F₅)₃ (CH₂Ph)}.OEt₂	tr P $\bar{1}$ 2	14.718(1) 14.957(1) 15.402(1)	100.40(0) 103.42(0) 99.60(0)	PtP₂SiO (P¹C₂Si¹C₂P²) 0.115	P^1,2 2.299(-,6) Si¹ 2.276 O 2.282	P^1,2,Si¹ 83.9(-,1.0) ^d P¹, P² 165.5 P^1,2, O 96.1(-,2.3) Si¹, O 178.4	[53]
[Pt{η³-cyh₂P(C₆H₄)Si (Me)(C₆H₄)Pcyh₂}(Ph)].OEt₂ (at 173 K)	tr P $\bar{1}$ 2	13.506(5) 14.057(5) 14.950(0)	116.38(0) 93.48(0) 112.52(0)	PtP₂SiC (P¹C₂Si¹C₂P²) 0.156	P^1,2 2.279(-,2) Si¹ 2.324 C 2.139	P^1,2,Si¹ 83.7(-,1) ^d P¹, P² 162.7 P^1,2, C 96.8(-,2) Si¹, C 175.1	[53]
[Pt{η³-Ph₂P(C₆H₄)Si(Me)(C₆H₄)PPh₂} (CH₂Ph)].CH₂Cl₂(at 193 K)	tr P $\bar{1}$ 2	13.586(1) 16.908(1) 19.771(2)	89.73(0) 76.03(0) 67.88(0)	PtP₂SiC (P¹C₂Si¹C₂P²) 0.151	P^1,2 2.260 Si¹ 2.356 C 2.201	P^1,2, Si¹ 82.6(-,3) ^d P¹, P² 163.0 P^1,2, C 97.0(-,1) Si¹, Cl 175.7	[53]
[Pt{η³-Prⁱ₂P(C₆H₄)Si(OH) (C₆H₄)PPrⁱ₂}(CO)].B(C₆F₅)₄ (at 120 K)	tr P $\bar{1}$ 2	13.658(0) 15.098(0) 15.201(0)	112.54(0) 94.60(0) 116.83(0)	PtP₂SiC (P¹C₂Si¹C₂P²) 0.179	P^1,2 2.325(-,3) Si¹ 2.365 OC 1.994	P^1,2, Si¹ 82.1(-,2) ^d P¹, P² 161.2 P^1,2, C 98.3(-,1.1) Si¹, C 173.4	[54]
[Pt{η³-Prⁱ₂P(C₆H₄)Si(H)(C₆H₄)PPrⁱ₂}(mes)] (at 110 K)	or P2₁2₁2₁ 6	8.186(0) 17.908(0) 21.795(1)		PtP₂SiC (P¹C₂Si¹C₂P²) 0.171	P^1,2 2.286(-,2) Si¹ 2.312 C 2.154	P^1,2, Si¹ 83.4(-,2) ^d P¹, P² 159.0 P^1,2, C 98.4(-,1.1) Si¹, C 177.0	[55]
[Pt{η³-Ph₂P(C₆H₄)Si(Me)(C₆H₄)PPh₂} (Cl)] (at 173 K)	m P4/c 4	9.911(1) 13.656(1) 23.845(3)	97.90(0)	PtP₂SiCl (P¹C₂Si¹C₂P²) 0.250	P^1,2 2.261 Si¹ 2.278 Cl 2.437	P^1,2, Si¹ 84.9(-,6) ^d P¹, P² 155.4 P^1,2, Cl 97.0(-,1) Si¹, Cl 169.3	[53]
[Pt{η³-Ph₂P(C₆H₄)Si(Me)(C₆H₄)PPh₂} (AlCl₃)].2(C₆H₅F) (at 193 K)	or P2₁2₁2₁ 4	16.111(1) 16.989(1) 17.437(1)		PtP₂SiCl (P¹C₂Si¹C₂P²) 0.181	P^1,2 2.289(-,0) Si¹ 2.285 Cl 2.438	P^1,2,Si¹ 84.7(-,1) ^d P¹, P² 164.2 P^1,2, Cl 96.8(2,3) Si¹, Cl 170.2	[53]
[Pt{η³-Prⁱ₂P(C₆H₄)Si(OH)(C₆H₄)PPrⁱ₂}(Cl)] (at 120 K)	m P2₁/c 4	8.465(0) 18.246(0) 16.810(0)	94.98(0)	PtP₂SiCl (P¹C₂Si¹C₂P²) 0.163	P^1,2 2.292(-,3) Si¹ 2.277 Cl 2.469	P^1,2, Si¹ 84.2(-,1) ^d P¹,P² 161.7 P^1,2,Cl 96.3(-,1.2) Si¹,Cl 175.1	[54]
[Pt{η³-Prⁱ₂P(C₆H₄)Si(H)(C₆H₄)Pcyh₂}(Cl)] (at 110 K)	m P2₁/n 4	12.420(8) 13.735(8) 15.539(10)	99.74(0)	PtP₂SiCl (P¹C₂Si¹C₂P²) 0.146	P^1,2 2.296 Si¹ 2.276 Cl 2.452	P^1,2, Si¹ 84.2(-,2) ^d P¹, P² 162.4 P^1,2, Cl 95.9(-,2.8) Si¹, Cl 177.1	[55]
[Pt{η³-cyh₂P(C₆H₄)Si(Me) (C₆H₄)Pcyh₂}(Cl)] (at 153 K)	m P2₁/c 4	13.104(3) 16.579(3) 17.770(4)	108.97(3)	PtP₂SiCl (P¹C₂Si¹C₂P²) 0.140	P^1,2 2.293 Si¹ 2.279 Cl 2.460	P^1,2, Si¹ 84.7(-,1) ^d P¹, P² 162.2 P^1,2, Cl 95.4(-,1.8) Si¹, Cl 178.0	[56]

Footnotes: a—Where more than one chemically equivalent distance or angle is present, the mean value is tabulated. The first number in parentheses is the e.s.d., and the second is the maximum deviation from the mean. b—The parameters, τ₄, were calculated τ₄ = 360 − (α + β)/141, where β and α are the two largest angles and assume the values of 0 and 1 for the perfect square planar and perfect tetrahedral geometries, respectively. c—The chemical identity of the coordinated atom or ligand is specified in these columns. d—Five-membered metallocyclic ring.

Table 4. Total mean values of angles and τ₄ of the respective complexes according to the plasticity of atoms.

Donor Atoms	α-X¹-Pt-Y (°)	β-P¹-Pt-P² (°)	τ₄
X¹(S)-Pt-(H)Y	162.2	175.6	0.151
X¹(S)-Pt-(B)Y	164.9	175.5	0.138
X¹(S)-Pt-(S)Y	164.3	175.5	0.128
X¹(H)-Pt-(H)Y	166.8	176.2	0.054

S—soft; H—hard; B—borderline; P¹, P²—soft.

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