Next Article in Journal
N-(4-Methoxyphenethyl)-2-oxo-2H-chromene-3-carboxamide
Previous Article in Journal
Syntheses of Chiral 2-Oxazolines from Isosorbide Epoxide Derivative
 
 
Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
Journals
Molbank
Volume 2025
Issue 1
10.3390/M1967
molbank-logo
Submit to this Journal Review for this Journal Propose a Special Issue
► Article Menu

Article Menu

share Share announcement Help format_quote Cite question_answer Discuss in SciProfiles
first_page
settings
Order Article Reprints
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Communication

Synthesis and Structural Characterization of Cobalt Complexes Ligated by N-Methyl(bis(diphenylphosphino)amine)

by
Mélaine Wang
1,2,
Isabelle Jourdain
1,*,
Michael Knorr
1,*,
Carsten Strohmann
3 and
Annika Schmidt
3
1
Institut UTINAM UMR 6213 CNRS, Université Marie et Louis Pasteur, F-25000 Besançon, France
2
URCOM, UR 3221, FR CNRS 3038, Université Le Havre Normandie, 25 Rue Philippe Lebon, F-76058 Le Havre, France
3
Anorganische Chemie, Technische Universität Dortmund, Otto-Hahn Straße 6, 44227 Dortmund, Germany
*
Authors to whom correspondence should be addressed.
Molbank 2025, 2025(1), M1967; https://doi.org/10.3390/M1967
Submission received: 15 January 2025 / Revised: 5 February 2025 / Accepted: 11 February 2025 / Published: 12 February 2025
(This article belongs to the Section Structure Determination)
Browse Figures
Versions Notes

Abstract

:
The reaction of the short-bite bis(diphosphino)amine ligand Ph2PN(Me)PPh2 (Medppa) with an equimolar amount of [Co2(CO)8] in toluene solution yielded the diphosphane-bridged complex bis(µ2-carbonyl)(µ-bis(diphenylphosphino)methylamine)-tetracarbonyl-dicobalt(0) (Co—Co) · 0.5 toluene, [Co2(CO)6(µ-Medppa)] 1. Using a 3:1 ratio, the ion-pair complex [Co(CO)(η2-Medppa)2][Co(CO)4] 2 was formed. The ionic intermediate [Co(CO)2(η2-Medppa)(η1-Medppa)][Co(CO)4] 3 was spectroscopically observed during the stoichiometric reaction involving [Co2(CO)8] and 2 eq. Medppa. Complexes 1 and 2 were characterized using IR and NMR spectroscopy and by single-crystal X-ray analysis performed at 100 K.

1. Introduction

One common method to stabilize the highly reactive [Co2(CO)8] is the addition of two equiv. of monodentate organophosphorus donors L (L = PR3, P(OR)3) leading to phosphane- or phosphite-substituted dinuclear cobalt(0) carbonyl complexes of general formula [Co2(CO)6L2] [1,2,3,4,5,6]. These organometallic species, often adopting a D3d symmetry bearing solely terminal carbonyl ligands and two trans-arranged L donors, have found numerous applications in homogenous catalysis (e.g., hydroformylation, hydroalkoxycarbonylation, hydrogenation, etc.) [3,7,8,9,10] or for further transformation with unsaturated organic ligands (e.g., Pauson Khand reaction, Nicholas reaction) [11,12,13,14]. Using so-called short-bite diphosphane ligands of the type R2PXPR2 (X = N, C) instead, both mononuclear chelate complexes and dinuclear diphosphine-bridged complexes [Co2(CO)6L∩L] can be formed [15,16]. In the latter case, the geometry of the dinuclear scaffold is altered with respect to its [Co2(CO)6L2] congeners, since one or two carbonyls are now μ2-bridging and the two P atoms are cis-arranged, forming five-membered Co-P-X-P-Co metallacycles.
Representative examples are [Co2(CO)4(μ-CO)2(μ2-dppa)] I (dppa = bis(diphenylphosphino)amine) [17], [Co2(CO)4(μ-CO)2(μ2-dppm)] II (dppm = bis(diphenylphosphino)methane [18] (Scheme 1) and [Co2(CO)4(μ-CO)2(μ2-dmpm)] (dmpm = bis(dimethylphosphino)methane [19]. These, in turn, have been employed as precursors for further carbonyl substitution reactions with other diphosphanes [20,21] or to construct dicobaltatetrahedrane clusters [Co2(CO)4L∩L(µ-RC≡CR′)] by treatment with internal and terminal alkynes [22,23,24]. Nowadays, dicobaltatetrahedranes [Co2(CO)6(µ-RC≡CR′)] constitute an emerging class of organometallic compounds relevant in bio-organometallic chemistry, since they display promising biological activity [25,26,27]. Surprisingly, the only structurally characterized Co2(CO)4L∩L(µ-RC≡CR′)]-type complex featuring biological activity is compound V [28], depicted in Scheme 1. We recently screened a series of dicobaltatetrahedranes bearing butynediol in silico by molecular docking studies for their potential as anticancer agents [29]. Among them, we synthesized complex III by treatment of in situ-prepared [Co2(CO)6(µ-Medppa)] with butynediol [29]. Along with IV [30], compound III constitutes, so far, the only representatives of Co-Co complexes spanned by Medppa.
With the idea in mind to prepare further Medppa-spanned [Co2(CO)4(μ-Medppa)(µ-RC≡CR′)] complexes as metallodrugs, in this communication, we describe the synthesis and spectroscopic characterization of [Co2(CO)4(μ-CO)2(μ2-Medppa)] 1, including its crystal structure. This study uses crystallographic characterization of the hitherto unknown ion-pair complex [Co(CO)(η2-Medppa)2][Co(CO)4] 2, obtained by reaction of [Co2(CO)8] with an excess of Medppa.

2. Results and Discussion

[Co2(CO)6(µ-Medppa)] 1 was obtained via treatment of [Co2(CO)8] with an equimolar amount of bis(diphenylphosphino)methylamine in toluene solution at 60 °C, as shown in Scheme 2. Upon cooling, small red-brown crystals of air-stable 1 were isolated, and elemental analysis confirmed their composition as toluene adduct. A few crystals of a minor product were also collected as yellow plates and identified as ion-pair complex [Co(CO)(η2-Medppa)2][Co(CO)4] 2. Such salt-like species are commonly observed as initial products during the reactions of PR3, P(OR)3, and diphosphanes with dicobalt octacarbonyl, evolving into neutral dinuclear complexes [1,2,21,31,32,33,34].
Using a 3:1 ligand-to-[Co2(CO)8] ratio, exclusively, 2 was formed. The disproportionation of [Co2(CO)8] leading to cobalt homonuclear ionic species is well established during reactions with other diphosphane ligands such as dppm, dppa, and iBudppa… [21,32,33,34,35], and, varying the condition reactions (solvent polarity, temperature, molar ratio), different ionic or neutral compounds have been characterized.
Initially, when employing a stoichiometric Medppa/[Co2(CO)8] 2:1 ratio, we evidenced, by spectroscopic characterization, formation of the intermediate [Co(CO)2(η1-Medppa)(η2-Medppa)][Co(CO)4] 3 (Scheme 2). This finding is in line with the observation of Ellermann et al. (i) that during the reaction of dppa with [Co2(CO)8], stoichiometric molar conditions induce only partial conversion and (ii) that for the complete reaction leading to [Co(CO)(η2-dppa)2][Co(CO)4], an excess of diphosphane is needed [21]. Therefore, for a straightforward preparation of the ion-pair complex 2, a 3:1 ratio of Medppa/[Co2(CO)8] was required.
The IR spectra of the isolated products recorded in CH2Cl2, shown in Figure 1, are very distinctive in the carbonyl region. The infrared spectrum of 1 reveals three intense terminal carbonyl vibrations at 2043, 2010 and 1984 cm−1, along with two characteristic ν(CO) bands at 1817 and 1785 cm−1, attributed to bridging COs. A simpler spectrum is obtained for 2 displaying a ν(CO) absorption at 1942 cm−1 ascribed to the cationic [Co(CO)(η2-Medppa)2]+ part and an intense band at 1884 cm−1 for the tetracarbonylcobaltate anion, coordinated by four tetrahedrally arranged carbonyls. These patterns are reminiscent of those reported for [Co2(CO)6(µ-dppa)] (I) in CH2Cl2 (2048, 2014, 1989, 1817 and 1796 cm−1) and [Co(CO)2(η2-dppa)2][Co(CO)4] recorded in THF (1944 and 1882 cm−1) [35]. Compared to I, a slight shift to lower wavenumbers is observed for carbonyl stretching frequencies in 1, reflecting the stronger electron-donating propensity of Medppa vs. dppa.
The 31P{1H} NMR spectra recorded in CDCl3 consist of singlets for 1 and 2 at δ 119.7 and 80.2 ppm, respectively. These values are in concordance with the ones reported for the Medppa-bridged dicobaltatetrahedrane [Co2(CO)4(µ-Medppa)(µ-PhC≡CH)] IV (δ 114.9 ppm) [30] and in the Medppa–chelate complex [(η2-Medppa)CpCo(MeCN)][PF6]2 (δ 77.9 ppm) [36]. During the disproportion reaction using a 2:1 ligand-to-[Co2(CO)8] ratio, a sample solution was analyzed using 31P{1H} NMR spectroscopy. The more complex spectrum (Figure S1) shows the coexistence of [Co(CO)(η2-Medppa)2]+ at δ 80.2 ppm and a set of multiplets attributed to the intermediate 3. Three signals are observed at δ 120.6 ppm (doublet of triplet, JPP = 143 Hz, 32 Hz), 75.3 ppm as a broad singlet (including free Medppa) and 61.7 ppm (d, JPP = 143 Hz). This A2MX fluxional system is consistent with the formation of a cationic trigonal bipyramidal [Co(CO)(η1-Medppa)(η2-Medppa)]+ species, giving rise to a doublet of triplets and a doublet due to the dangling monocoordinated Medppa and a broad signal to the chelating ligand [35,37].
In addition to the spectroscopic characterization of 1 in solution, the dinuclear complex was also unambiguously analyzed using X-ray diffraction performed at 100 K. Complex 1 crystallizes in the triclinic space group P-1, containing a half molecule of disordered toluene (Table S1). As shown in Figure 2, in this organometallic species, the two crystallographically non-equivalent Co1 and Co2 centers are linked through a metal–metal bond and spanned by the Medppa ligand forming a five-membered cycle. The Co–Co bond is further spanned by two μ2-carbonyls, and the coordination sphere around each Co atom is completed by two terminal carbonyls, which are cis-arranged with respect to the Co–P bonds. Therefore, the overall structure is quite reminiscent of those of [Co2(CO)4(μ-CO)2(μ2-dppa)] · 0.5 benzene (CSD refcode JAZFUM), [Co2(CO)4(μ-CO)2(μ2-dppm)] (CSD refcode PPACCP) and [Co2(CO)4(μ-CO)2(μ2-dcpm)] (dcpm = bis(dicyclohexylphosphino)methane; CSD refcode PAJRUP) [17,18,38]. The Co–Co bond length of 2.4595(5) Å is similar to that of its dppa-, dppm- and dcpm-analogues (2.457(3), 2.4568(5)) and 2.4618(7) Å. Other relevant averaged bond lengths of 1 are listed in Table 1 and compared with those of analogous diphosphane-spanned compounds. The observation that the P-X-P angles of the P-C-P-spanned derivatives are considerably more acute than those of the P-N-P-spanned complexes is noteworthy. This difference between the P-C-P and P-N-P angles is already present in the free diphosphine ligands. The P-C-P bond angle in dppm is 106.2(3)° [39] and the P-N-P angles are 118.9(2)° and 114.86(4)° in the nitrogen-bridged diphosphines dppa and Medppa, respectively [30,40,41]. Based on the structural data, the authors of [30] discuss a partial double bond character of the P-N bond and a trigonal planar arrangement around the N atom of the diphosphinoamines, while the sp3-hybridized C center in dppm has a tetrahedral geometry of 106.3°.
There are no particular supramolecular features; the disordered toluene molecule is intercalated between two neighbored dicobalt species through weak C−H···O and aromatic contacts (d(O6···H33) = 2.600, d(O6···H37) = 2.640, d(O2···H34) = 2.670, d(H21---C38 = 2.779 Å). Further weak intermolecular interactions occur in the crystal between the dinuclear moieties (d(H10···C17) = 2.774, d(H11···C27) = 2.791, d(H1C···C5) = 2.670 Å).
An X-ray diffraction investigation was performed at 100 K on crystals of compound 2 crystallizing in the monoclinic space group P21/n (Table S1). The asymmetric unit contains one [Co(CO)(η2-Medppa)2]+ cation and one anion [Co(CO)4]− (Figure 3). The tetracarbonylcobaltate anion adopts a tetrahedral geometry with C–Co–C angles ranging from 107.01(10) to 111.52(10)° (average angle of 109.45°). These values and other geometrical parameters fit well with those reported for complexes including the [Co(CO)4]− anion [9,33,37]. Selected bond lengths and angles of the cationic moiety [Co(CO)(η2-Medppa)2]+ are listed in Table 2 and compared with those reported for other [Co(CO)(η2-dppx)2][Co(CO)4] complexes. The cationic cobalt center in 2 is five-coordinated by one equatorially arranged CO and by two chelating Medppa ligands, with P2 and P3 occupying the axial site and P1 and P4 occupying the equatorial sites of the polyhedron. The Co–P distances vary from 2.1870(5) Å to 2.2224(5) Å and the P–Co–P angles span the range 72.10(10)–171.00(2)°. This Co cation adopts a distorted trigonal bipyramidal geometry with a τ5 value of 0.72. The τ5 geometry index was calculated according to τ5 = (β − α)/60, where α and β are the largest angles around the metal center with β > α [42]. The same geometry is reported for the cation in [Co(CO)(η2-dppm)2][Co(CO)4] (CSD refcode KOKTEJ, τ5 = 0.64), [Co(CO)(η2-tBudppa)2][Co(CO)4] (CSD refcode SAKFUJ, τ5 = 0.85) and [Co(CO)(η2-dppa)2][BPh4] · THF (CSD refcode LIQSUZ, τ5 = 0.74), while a distorted square pyramidal arrangement is observed for [Co(CO)(η2-dppm)2][Co(CO)4] · 2THF (CSD refcode LIQTAG, τ5 = 0.25) and [Co(CO)(η2-iBudppa)2][Co(CO)4] (CSD refcode WEYJAL, τ5 = 0.16) [9,33,35,37]. As expected, the P–N–P angles of 100.42(9) and 99.88(8)° measured for the chelating ligands are significantly smaller than those in 1, where Medppa acts as a μ2-bridging ligand (P–N–P angle = 123.19(9)°).
Weak intramolecular interactions occur between the tetracarbonylcobaltate and the phenyl groups of the cationic species (d(H36···O5) = 2.562 Å, d(H4···C52) = 2.751 Å), and intermolecular contacts involving the oxygen atoms of [Co(CO)4]− are observed with the PPh2 and the NMe groups of Medppa (d(H43···O2) = 2.424 Å, d(H38C···O3) = 2.524 Å).

3. Materials and Methods

Dicobalt octacarbonyl was commercially purchased from Thermo Scientific. Medppa was synthesized as previously reported [43]. The reactions were performed under an argon atmosphere. The 1H-, 31P- and 13C-NMR spectra were recorded on a Bruker AC 400 (Bruker, Wissembourg, France) at 400, 121.50 and 100.62 MHz, respectively, using CDCl3 as solvent. Infrared spectra were recorded on a Vertex 70 spectrometer (Bruker, Wissembourg, France) using a Platinum ATR accessory equipped with a diamond crystal or on a Bruker Alpha II IRTF spectrometer in solution.
Bis(µ2-carbonyl)(µ2-bis(diphenylphosphino)methylamine)-tetracarbonyl-dicobalt(0)·toluene, [Co2(CO)6(µ-Medppa)] 1: Medppa (225 mg, 0.562 mmol) was added to a stirred solution of Co2(CO)8 (175.0 mg, 0.511 mmol) in toluene (10 mL). An immediate gas evolution was observed. The reaction mixture was then heated to 60 °C for 5 h. The solution was cooled to room temperature prior to lowering its temperature to 4 °C. Product 1 crystallized as red-brown crystals which were collected via filtration. Yield: 69%. Anal. Calc. for C31H23Co2NO6P2·0.5C7H8 (M.W = 731.37 g.mol−1): C, 56.66; H, 3.72; N, 1.92%. Detected: C, 56.58; H, 3.68; N, 1.95%. 1H-NMR (CDCl3) at 298 K: δ 2.57 (s, 3H, CH3), 7.05 (m, 8H, CH Ar), 7.13 (m, CH Ar), 7.60 (m, CH Ar) ppm. 13C{1H}-NMR (CDCl3) at 298 K: δ 32.9 (CH3), 125.1–132.4 (Ph, Medppa and toluene), 214.7 (CO) ppm. 31P{1H}-NMR (CDCl3) at 298 K: δ 119.7 ppm.
Carbonylbisη2-bis(diphenylphosphino)methylamine)cobalt(I)-tetracarbonylcobaltate(-I) [Co(CO)(η2-Medppa)2][Co(CO)4] 2: Medppa (441 mg, 3 mmol) was added to a stirred solution of Co2(CO)8 (342.0 mg, 1 mmol) in toluene (5 mL). An immediate gas evolution was observed. The reaction mixture was stirred at room temperature for 4 h. The solution was then cooled to 4 °C. Product 2 crystallized as yellow plates which were collected via filtration. Yield: 58%. Anal. Calc. for C55H46Co2N2O5P4 (M.W = 1056.74 g.mol−1): C, 62.51; H, 4.38; N, 2.65%. Detected: C, 62.83; H, 4.45; N, 2.78%. 1H-NMR (CDCl3) at 298 K: δ 2.14 (br s, 6H, CH3), 6.72–7.63 (m, 40H, CH Ar) ppm. 31P{1H}-NMR (CDCl3) at 298 K: δ 80.2 ppm.
The crystallographic data collection was performed on a Bruker D8 Venture four-circle diffractometer from Bruker AXS GmbH (Karlsruhe, Germany). Photon II from Bruker AXS GmbH was used as a CPAD detector, and the X-ray sources were a Microfocus source IµS Mo from Incoatec GmbH with HELIOS mirror optics and a single-hole collimator from Bruker AXS GmbH. Programs used for data collection were APEX4 Suite [44] (v2021.10-0) and integrated programs SAINT (V8.40A; integration as well as SADABS (2018/7; absorption correction) from Bruker AXS GmbH [44]. The SHELX programs were used for further processing [45]. The solution of the crystal structures was analyzed with the help of the program SHELXT [46] and structure refinement was performed with SHELXL [47]. The processing and finalization of the crystal structure data were carried out with OLEX2 v1.5 [48]. All non-hydrogen atoms were refined anisotropically. All H atoms were refined freely using independent values for each Uiso(H).
Crystal data for C34.5H27Co2NO6P2 were as follows: M = 731.37 g.mol−1, red crystals, crystal size 0.394 × 0.244 × 0.211 mm3, triclinic, space group P-1: a = 10.4585(13) Å, b = 12.368(2) Å, c = 15.062(3) Å, α = 67.600(6)°, β = 87.814(7)°, γ = 66.131(7)°, V = 1631.6(5) Å3, Z = 2, Dcalc = 1.489 g/cm3, T = 100 K, h = −14 ≤ h ≤ 14, k = −17 ≤ k ≤ 17, l = −21 ≤ l ≤ 20, GOF = 1.014, R1 = 0.0334, wR2 = 0.0743 for 9926 reflections with I > = 2σ (I) and 9926 independent reflections. The largest diff. peak/hole was e Å−3 0.56/−0.41. The structure was solved using direct methods and refined using full-matrix least-squares against F2.
Crystal data for C55H46Co2N2O5P4 were as follows: M = 1056.68 g.mol−1, yellow plates, crystal size 0.204 × 0.187 × 0.164 mm3, monoclinic, space group P21/n: a = 11.7166(10)Å, b = 11.3888(7) Å, c = 37.707(3) Å, α = 90°, β = 98.863(3)°, γ = 90°, V = 4971.4(6) Å3, Z = 4, Dcalc = 1.412 g/cm3, T = 100 K, h = −16 ≤ h ≤ 15, k = −14 ≤ k ≤ 14, l = −47 ≤ l ≤ 53, GOF = 1.060, R1 = 0.0402, wR2 = 0.0732 for 13,797 reflections with I > = 2σ (I) and 13,797 independent reflections. The largest diff. peak/hole was e Å−3 0.46/−0.44. The structure was solved using direct methods and refined using full-matrix least-squares against F2.
Data were collected using graphite-monochromated MoKα radiation λ = 0.71073 Å and were deposited in the Cambridge Crystallographic Data Centre as 2416934 (1) and 2416981 (2). (Supplementary Materials). The data can be obtained free of charge from the Cambridge Crystallographic Data Centre via http://www.ccdc.cam.ac.uk/getstructures (accessed on 11 February 2025).

4. Conclusions

We have demonstrated that the result of the addition of Medppa to [Co2(CO)8] depends on the metal-to-ligand ratio. Using a 1:1 ratio yields the diphosphane-bridged complex [Co2(CO)6(µ-Medppa)] 1, whereas employing a 3:1 ratio provides the ion-pair complex [Co(CO)(η2-Medppa)2][Co(CO)4] 2. Using solely a 2:1 ratio also allows for the spectroscopic observation of salt [Co(CO)2(η2-Medppa)(η1-Medppa)][Co(CO)4] 3 as an intermediate, in which the cation is coordinated by both a chelating and dangling Medppa ligand. The coordination of alkynes and the investigation of the biological activity of the resulting dicobaltatetrahedrane clusters [Co2(CO)4(μ2-Medppa)(µ-RC≡CR′)] will be the topic of a forthcoming study.

Supplementary Materials

CIF file, Check-CIF report, and 31P{1H} NMR spectrum.

Author Contributions

I.J. and M.W. prepared the compound; C.S. and A.S. collected the X-ray data and solved the structure; I.J. and M.K. designed the study, analyzed the data and wrote the paper. All authors have read and agreed to the published version of the manuscript.

Funding

This work was supported by the EIPHI Graduate school (contract “ANR-17-EURE-0002”), by the Bourgogne-Franche-Comté Region and the Normandie Region through the BacMetDrugs project.

Data Availability Statement

The X-ray data are in the CCDC as stated in the paper.

Acknowledgments

We thank S. Beffy from the Plateforme Chimie UTINAM for recording some IR and NMR spectra and S. Adache from SynBioN (Université de Lorraine-CNRS–http://synbion.univ-lorraine.fr/accueil/) for the elemental analyses (accessed on 11 February 2025).

Conflicts of Interest

The authors declare no conflicts of interest.

References

  1. Manning, A.R. Infrared Spectra of Some Derivatives of Octacarbonyldicobalt. J. Chem. Soc. Inorg. Phys. Theor. 1968, 1135–1137. [Google Scholar] [CrossRef]
  2. Booth, B.L.; Gardner, M.; Haszeldine, R.N. A Carbonyl-Bridged, Phosphite-Substituted Cobalt Carbonyl Derivative. J. Chem. Soc. Chem. Commun. 1969, 1388–1389. [Google Scholar] [CrossRef]
  3. Haumann, M.; Meijboom, R.; Moss, J.R.; Roodt, A. Synthesis, Crystal Structure and Hydroformylation Activity of Triphenylphosphite Modified Cobalt Catalysts. Dalton Trans. 2004, 1679–1686. [Google Scholar] [CrossRef] [PubMed]
  4. Jourdain, I.; Knorr, M.; Brieger, L.; Strohmann, C. Synthesis of Tris(Arylphosphite)-Ligated Cobalt(0) Complexes [Co2(CO)6{P(OAr)3}2], and Their Reactivity towards Phenylacetylene and Diphenylacetylene. Adv. Chem. Res. 2020, 2, 1–20. [Google Scholar] [CrossRef]
  5. Casati, N.; Macchi, P.; Sironi, A. Molecular Crystals under High Pressure: Theoretical and Experimental Investigations of the Solid-Solid Phase Transitions in [Co2(CO)6(XPh3)2] (X = P, As). Chem. Eur. J. 2009, 15, 4446–4457. [Google Scholar] [CrossRef]
  6. Bartik, T.; Bartik, B.; Hanson, B.E.; Whitmire, K.H.; Guo, I. Reactions of Trisulfonated Triphenylphosphine, TPPTS, with Cobalt Carbonyls in Water. Inorg. Chem. 1993, 32, 5833–5837. [Google Scholar] [CrossRef]
  7. Weber, R.; Englert, U.; Ganter, B.; Keim, W.; Möthrath, M. Hydroformylation of Epoxides Catalyzed by Cobalt and Hemilabile P–O Ligands. Chem. Commun. 2000, 1419–1420. [Google Scholar] [CrossRef]
  8. Meijboom, R.; Haumann, M.; Roodt, A.; Damoense, L. Synthesis, Spectroscopy, and Hydroformylation Activity of Sterically Demanding, Phosphite-Modified Cobalt Catalysts. Helv. Chim. Acta 2005, 88, 676–693. [Google Scholar] [CrossRef]
  9. Zhao, J.; Wu, P.; Lai, E.; Li, J.; Chen, Y.; Jiang, W.; Wang, B.; Zhu, H. Cobalt Carbonyls Stabilized by N,P-Ligands: Synthesis, Structure, and Catalytic Property for Ethylene Oxide Hydroalkoxycarbonylation. Chem. Asian J. 2021, 16, 3453–3461. [Google Scholar] [CrossRef]
  10. Amézquita-Valencia, M.; Ramírez-Garavito, R.; Toscano, R.A.; Cabrera, A. Hydrogenation of α-Enaminoketones with Cobalt Phosphine-Modified Catalysts. Catal. Commun. 2013, 33, 29–33. [Google Scholar] [CrossRef]
  11. Pauson, P.L.; Khand, I.U. Uses of Cobalt-Carbonyl Acetylene Complexes in Organic Synthesis. Ann. N. Y. Acad. Sci. 1977, 295, 2–14. [Google Scholar] [CrossRef]
  12. Gibson, S.E.; Stevenazzi, A. The Pauson–Khand Reaction: The Catalytic Age Is Here! Angew. Chem. Int. Ed. 2003, 42, 1800–1810. [Google Scholar] [CrossRef] [PubMed]
  13. Blanco-Urgoiti, J.; Añorbe, L.; Pérez-Serrano, L.; Domínguez, G.; Pérez-Castells, J. The Pauson–Khand Reaction, a Powerful Synthetic Tool for the Synthesis of Complex Molecules. Chem. Soc. Rev. 2004, 33, 32–42. [Google Scholar] [CrossRef]
  14. Golovko, V.B.; Hope-Weeks, L.J.; Mays, M.J.; McPartlin, M.; Sloan, A.M.; Woods, A.D. Synthesis of Cobalt-Containing Cyclophanes, and the Formation of an Unprecedented Seven-Membered Cyclic Diyne. New J. Chem. 2004, 28, 527–534. [Google Scholar] [CrossRef]
  15. Mague, J.T. “Short-Bite” Ligands in Cluster Synthesis. J. Clust. Sci. 1995, 6, 217–269. [Google Scholar] [CrossRef]
  16. Anandhi, U.; Holbert, T.; Lueng, D.; Sharp, P.R. Platinum and Palladium Imido and Oxo Complexes with Small Natural Bite Angle Diphosphine Ligands. Inorg. Chem. 2003, 42, 1282–1295. [Google Scholar] [CrossRef]
  17. Ellermann, J.; Geheeb, N.; Zoubek, G.; Thiele, G. Complex Chemistry of Polyfunctional Ligands, 411 Synthesis and Crystal Structure of Di-µ-Carbonyl-µ-Bis(Diphenylphosphino)Amine-Tetracarbonyl-Dicobalt(0) (Co—Co) · 0.5 Benzene. Z. Für Naturforsch. B 1977, 32, 1271–1276. [Google Scholar] [CrossRef]
  18. Chang; Lee, J.-C.; Hong, F.-E. Design, Synthesis, Application, and DFT Investigation of Suzuki−Miyaura Reactions of a Dicobalt Carbonyl-Containing Phosphine Ligand. Organometallics 2005, 24, 5686–5695. [Google Scholar] [CrossRef]
  19. Lisic, E.C.; Hanson, B.E. Solution Structure and Dynamics of Co2(CO)6(L-L) and Co4(CO)8(L-L)2 Molecules. Inorg. Chem. 1986, 25, 812–815. [Google Scholar] [CrossRef]
  20. Lisic, E.C.; Hanson, B.E. Synthesis and Reactivity of Cobalt Dimers of the Type Co2(CO)3(L-L)2I2. Crystal Structure of [Co2(CO)2(µ-CO)(µ-I)(Me2PCH2PMe2)(Ph2PCH2PPh2)]I. Organometallics 1987, 6, 512–516. [Google Scholar] [CrossRef]
  21. Pohl, D.; Ellermann, J.; Knoch, F.A.; Moll, M.; Bauer, W. Chemie Polyfunktioneller Moleküle: CXIII Komplexe des Dicobaltoctacarbonyls mit den Liganden Bis(diphenylphosphino)amin und -amid. J. Organomet. Chem. 1994, 481, 259–274. [Google Scholar] [CrossRef]
  22. Hong, F.-E.; Ho, Y.-J.; Chang, Y.-C.; Lai, Y.-C. Palladium Catalyzed Suzuki Coupling Reactions Using Cobalt-Containing Bulky Phosphine Ligands. Tetrahedron 2004, 60, 2639–2645. [Google Scholar] [CrossRef]
  23. Huang, P.-C.; Hong, F.-E. Amination and Suzuki Coupling Reactions Catalyzed by Palladium Complexes Coordinated by Cobalt-Containing Monodentate Phosphine Ligands with Bis-Trifluoromethyl Substituents on Bridged Arylethynyl: Observation of Some Unusual Metal-Containing Compounds. J. Organomet. Chem. 2009, 694, 113–121. [Google Scholar] [CrossRef]
  24. Mohamed, A.S.; Jourdain, I.; Knorr, M.; Boullanger, S.; Brieger, L.; Strohmann, C. Heterodinuclear Diphosphane-Bridged Iron–Platinum Diyne Complexes as Metalloligands for the Assembly of Polymetallic Systems (Fe, Pt, Co). J. Clust. Sci. 2019, 30, 1211–1225. [Google Scholar] [CrossRef]
  25. Schmidt, K.; Jung, M.; Keilitz, R.; Schnurr, B.; Gust, R. Acetylenehexacarbonyldicobalt Complexes, a Novel Class of Antitumor Drugs. Inorg. Chim. Acta 2000, 306, 6–16. [Google Scholar] [CrossRef]
  26. Vessières, A.; Top, S.; Vaillant, C.; Osella, D.; Mornon, J.-P.; Jaouen, G. Estradiols Modified by Metal Carbonyl Clusters as Suicide Substrates for the Study of Receptor Proteins: Application to the Estradiol Receptor. Angew. Chem. Int. Ed. Engl. 1992, 31, 753–755. [Google Scholar] [CrossRef]
  27. Neukamm, M.A.; Pinto, A.; Metzler-Nolte, N. Synthesis and Cytotoxicity of a Cobaltcarbonyl–Alkyne Enkephalin Bioconjugate. Chem. Commun. 2008, 232–234. [Google Scholar] [CrossRef]
  28. Kaczmarek, R.; Korczyński, D.; Królewska-Golińska, K.; Wheeler, K.A.; Chavez, F.A.; Mikus, A.; Dembinski, R. Organometallic Nucleosides: Synthesis and Biological Evaluation of Substituted Dicobalt Hexacarbonyl 2′-Deoxy-5-Oxopropynyluridines. ChemistryOpen 2018, 7, 237–247. [Google Scholar] [CrossRef]
  29. Mohamed, A.S.; Jourdain, I.; Knorr, M.; Beffy, S.; Elmi Fourreh, A.; Siddique, F.; Chtita, S.; Strohmann, C.; Schmidt, A.; Hussien, P.M. Synthesis and Crystallographic Investigation of Dicobalt Tetrahedrane Complexes Ligated by 2-Butyne-1,4-Diol. In Silico Evaluation of Their Efficiency as Anticancer Metallodrugs. J. Mol. Struct. 2024, 1321, 140108. [Google Scholar] [CrossRef]
  30. Gimbert, Y.; Robert, F.; Durif, A.; Averbuch, M.-T.; Kann, N.; Greene, A.E. Synthesis and Characterization of New Binuclear Co(0) Complexes with Diphosphinoamine Ligands. A Potential Approach for Asymmetric Pauson−Khand Reactions. J. Org. Chem. 1999, 64, 3492–3497. [Google Scholar] [CrossRef]
  31. Lee, K.Y.; Kochi, J.K. Oxidation-Reduction of Carbonylcobalt Cation-Anion Pairs in Coupling to Dimeric Cobalt Carbonyls. Inorg. Chem. 1989, 28, 567–578. [Google Scholar] [CrossRef]
  32. de Leeuw, G.; Field, J.S.; Haines, R.J.; Minshall, E.M. Neutral and Ionic Products of the Reactions of Tetra-Alkoxy and Tetraphenoxy Diphosphazane Ligands with Dicobalt Octacarbonyl: Crystal Structure of [Co(CO){(PriO)2PN(Et)P(OPri)2}2][BPh4]. S. Afr. J. Chem. 1988, 41, 9–16. [Google Scholar]
  33. Zhang, Z.-Z.; Yu, A.; Xi, H.-P.; Wang, R.-J.; Wang, H.-G. Formation and Structure of [Co{Ph2PN(iBu)PPh2-P,P′}2(CO)][Co)(CO)4]—A Cage Molecule-Pair or an Ion-Pair Complex? J. Organomet. Chem. 1994, 470, 223–229. [Google Scholar] [CrossRef]
  34. Dura, L.; Spannenberg, A.; Beweries, T. Crystal Structure of Tricarbonyl(N-diphenyl phosphanyl-N,N′-diisopropyl-p-phenyl phosphonous diamide-κP,P′)Cobalt(I) Tetracarbonyl cobaltate(−I) Toluene 0.25-Solvate. Acta Crystallogr. Sect. E 2014, 70, 533–535. [Google Scholar] [CrossRef]
  35. Bauer, W.; Ellermann, J.; Dotzler, M.; Pohl, D.; Heinemann, F.W.; Moll, M. Kristallstrukturelle, Festkörper-31P-CP/MAS-NMR, TOSS, 31P-COSY-NMR und mechanistische Beiträge zur Koordinationschemie des Octacarbonyldicobalts mit den Liganden Bis(diphenylphosphanyl)amin, Bis(diphenylphosphanyl)methan und 1,1,1-Tris(diphenylphosphanyl)ethan. Z. Anorg. Allg. Chem. 2000, 626, 574–587. [Google Scholar] [CrossRef]
  36. Cook, A.W.; Emge, T.J.; Waldie, K.M. Insights into Formate Oxidation by a Series of Cobalt Piano-Stool Complexes Supported by Bis(Phosphino)Amine Ligands. Inorg. Chem. 2021, 60, 7372–7380. [Google Scholar] [CrossRef]
  37. Elliot, D.J.; Holah, D.G.; Hughes, A.N.; Magnuson, V.R.; Moser, I.M.; Puddephatt, R.J.; Xu, W. New Routes to Cobalt(I) Bis(Diphenylphosphino)Methane Carbonyl Complexes Containing Monocoordinated and Chelating Ligands: Structure of [Co(η2-dppm)2(CO)][Co(CO)4]. Organometallics 1991, 10, 3933–3939. [Google Scholar] [CrossRef]
  38. Clément, S.; Guyard, L.; Khatyr, A.; Knorr, M.; Rousselin, Y.; Kubicki, M.M.; Mugnier, Y.; Richeter, S.; Gerbier, P.; Strohmann, C. Synthesis, Crystallographic and Electrochemical Study of Ethynyl [2.2]Paracyclophane-Derived Cobalt Metallatetrahedranes. J. Organomet. Chem. 2012, 699, 56–66. [Google Scholar] [CrossRef]
  39. Schmidbaur, H.; Reber, G.; Schier, A.; Wagner, F.E.; Müiller, G. Structural Correlations between trans- and cis-Bis(diphenylphosphino)Ethene, Bis(diphenylphosphino)methane and their Chlorogold(I) Complexes. Inorg. Chim. Acta 1988, 147, 143–150. [Google Scholar] [CrossRef]
  40. Nöth, H.; Fluck, E. Röntgenstrukturuntersuchungen an Verbindungen Mit P—NH—P-Gerüst/X-Ray Structural Studies on Compounds with a P-NH-P Backbone. Z. Naturforsch. B 1984, 39, 744–753. [Google Scholar] [CrossRef]
  41. Albert Cotton, F.; Kühn, F.E.; Yokochi, A. Synthesis and Structure of trans-[Di(μ-Acetato)Dichlorodi-(μ-Bis(Diphenylphosphino)Methylamine)Dimolybdenum(II)] and the Structure of Bis(Diphenylphosphino)Methylamine. Inorg. Chim. Acta 1996, 252, 251–256. [Google Scholar] [CrossRef]
  42. Addison, A.W.; Rao, T.N.; Reedijk, J.; Rijn, J.; van Verschoor, G.C. Synthesis, Structure, and Spectroscopic Properties of Copper(II) Compounds Containing Nitrogen–Sulphur Donor Ligands; the Crystal and Molecular Structure of Aqua [1,7-Bis(N-Methylbenzimidazol-2′-Yl)-2,6-Dithiaheptane]Copper(II) Perchlorate. J. Chem. Soc. Dalton Trans. 1984, 1349–1356. [Google Scholar] [CrossRef]
  43. Ewart, G.; Lane, A.P.; McKechnie, J.; Payne, D.S. Tervalent Phosphorus–Nitrogen Chemistry. Part II. Mono- and Bis-(Disphenylphosphino)Alkylamines. J. Chem. Soc. 1964, 1543–1547. [Google Scholar] [CrossRef]
  44. Bruker. APEX4; Bruker AXS Inc.: Madison, WI, USA, 2021. [Google Scholar]
  45. Sheldrick, G.M. A Short History of SHELX. Acta Crystallogr. A 2008, 64, 112–122. [Google Scholar] [CrossRef]
  46. Sheldrick, G.M. SHELXT—Integrated Space-Group and Crystal-Structure Determination. Acta Crystallogr. Sect. Found. Adv. 2015, 71, 3–8. [Google Scholar] [CrossRef]
  47. Sheldrick, G.M. Crystal Structure Refinement with SHELXL. Acta Crystallogr. Sect. C Struct. Chem. 2015, 71, 3–8. [Google Scholar] [CrossRef]
  48. Dolomanov, O.; Bourhis, L.; Gildea, R.; Howard, J.; Puschmann, H. OLEX2: A Complete Structure Solution, Refinement and Analysis Program. J. Appl. Cryst. 2009, 42, 339–341. [Google Scholar] [CrossRef]
Molbank 2025 m1967 sch001
Scheme 1. Examples of diphosphane-spanned dicobalthexacarbonyl and dicobaltatetrahedrane complexes [17,18,28,29,30].
Scheme 1. Examples of diphosphane-spanned dicobalthexacarbonyl and dicobaltatetrahedrane complexes [17,18,28,29,30].
Molbank 2025 m1967 sch001
Molbank 2025 m1967 sch002
Scheme 2. Synthesis of compounds 1, 2 and spectroscopic detection of 3, featuring chelating, dangling and bridging bonding modes of Medppa.
Scheme 2. Synthesis of compounds 1, 2 and spectroscopic detection of 3, featuring chelating, dangling and bridging bonding modes of Medppa.
Molbank 2025 m1967 sch002
Molbank 2025 m1967 g001
Figure 1. Comparison of the IR spectra of [Co2(CO)6(µ-Medppa)] 1 (blue) and [Co(CO)(η2-Medppa)2][Co(CO)4] 2 (red) in the carbonyl region (recorded in CH2Cl2).
Figure 1. Comparison of the IR spectra of [Co2(CO)6(µ-Medppa)] 1 (blue) and [Co(CO)(η2-Medppa)2][Co(CO)4] 2 (red) in the carbonyl region (recorded in CH2Cl2).
Molbank 2025 m1967 g001
Molbank 2025 m1967 g002
Figure 2. Molecular structure of 1. All H atoms are omitted for clarity. Selected bond lengths (Å) and angles (deg): Co1-Co2 2.4595(5), Co1-P1 2.2273(5), Co1-C26 1.9493(16), Co1-C27 1.9514(18), Co1-C30 1.7843(18), Co1-C31 1.8096(17), Co2-P2 2.2456(5), Co2-C26 1.9206(16), Co2-C27 1.9514(19), Co2-C28 1.8174(19), Co2-C29 1.7846(17), P1-N 1.7047(14), P2-N 1.7031(16), P1-Co1-Co2 96.439(18), C26-Co1-P1 84.86(5), C27-Co1-P1 144.93(6), C27-Co1-C26 82.24(7), C30-Co1-P1 107.14(6), C30-Co1-C26 90.72(7), C30-Co1-C27 105.50(8), C30-Co1-C31 104.01(8), C31-Co1-P1 95.89(5), C31-Co1-C26 164.24(7), C31-Co1-C27 88.35(7), P2-Co2-Co1 97.338(19), C26-Co2-P2 86.95(5), C26-Co2-C27 82.51(7), C27-Co2-P2 144.36(5), C28-Co2-P2 92.87(7), C28-Co2-C26 161.74(8), C28-Co2-C27 87.13(9), C29-Co2-P2 112.46(6), C29-Co2-C26 93.91(7), C29-Co2-C27 102.98(8), C29-Co2-C28 103.98(8).
Figure 2. Molecular structure of 1. All H atoms are omitted for clarity. Selected bond lengths (Å) and angles (deg): Co1-Co2 2.4595(5), Co1-P1 2.2273(5), Co1-C26 1.9493(16), Co1-C27 1.9514(18), Co1-C30 1.7843(18), Co1-C31 1.8096(17), Co2-P2 2.2456(5), Co2-C26 1.9206(16), Co2-C27 1.9514(19), Co2-C28 1.8174(19), Co2-C29 1.7846(17), P1-N 1.7047(14), P2-N 1.7031(16), P1-Co1-Co2 96.439(18), C26-Co1-P1 84.86(5), C27-Co1-P1 144.93(6), C27-Co1-C26 82.24(7), C30-Co1-P1 107.14(6), C30-Co1-C26 90.72(7), C30-Co1-C27 105.50(8), C30-Co1-C31 104.01(8), C31-Co1-P1 95.89(5), C31-Co1-C26 164.24(7), C31-Co1-C27 88.35(7), P2-Co2-Co1 97.338(19), C26-Co2-P2 86.95(5), C26-Co2-C27 82.51(7), C27-Co2-P2 144.36(5), C28-Co2-P2 92.87(7), C28-Co2-C26 161.74(8), C28-Co2-C27 87.13(9), C29-Co2-P2 112.46(6), C29-Co2-C26 93.91(7), C29-Co2-C27 102.98(8), C29-Co2-C28 103.98(8).
Molbank 2025 m1967 g002
Molbank 2025 m1967 g003
Figure 3. Molecular structure of 2. All H atoms are omitted for clarity.
Figure 3. Molecular structure of 2. All H atoms are omitted for clarity.
Molbank 2025 m1967 g003
Table 1. Comparison of relevant bond lengths (Å) and angles (°) in 1 with those of other crystallographically characterized [Co2(CO)6(µ-dppx)] complexes.
Table 1. Comparison of relevant bond lengths (Å) and angles (°) in 1 with those of other crystallographically characterized [Co2(CO)6(µ-dppx)] complexes.
1dppadppmdcpm
Co–Co2.4595(5)2.45692.4569(4)2.4618(7)
Co–P2.2342.2292.2522.262
Co–μC1.9391.9141.9381.927
Co–C1.7991.7651.7931.805
P–X1.7041.6891.8501.843
PXP123.19(9)126.22115.9(1)117.73(17)
CSD referenceThis workPPACCP [17]JAZFUM [18]PAJRUP [38]
Table 2. Comparison of relevant bond lengths (Å) and angles (°) for the cationic moiety in 2 and related crystallographically characterized [CoI(dppx)2(CO)][Co-I(CO)4] salts.
Table 2. Comparison of relevant bond lengths (Å) and angles (°) for the cationic moiety in 2 and related crystallographically characterized [CoI(dppx)2(CO)][Co-I(CO)4] salts.
2iBudppadppm dppm·2THF
Co–C1.7441(19)1.796(9)1.735(12)1.786(7)
Co–P2.2224(5)2.179(2)2.217(3)2.195(2)
2.2194(5)2.174(2)2.208(3)2.204(2)
2.1870(5)2.180(2)2.207(3)2.210(2)
2.1931(5)2.173(2)2.227(3)2.203(2)
P–Co–C94.21(6)100.0(2)93.1(3)97.7(2)
94.79(6)100.3(2)94.9(3)98.0(2)
122.31(7)103.8(2)113.8(4)104.9(2)
127.81(7)105.9(2)112.5(4)107.8(2)
P–Co–P171.00(2)159.74(7)172.05(11)164.23(8)
109.87(2)150.29(7)133.73(12)147.26(8)
102.36(2)102.24(6)102.53(11)99.84(8)
102.62(2)103.17(6)103.37(11)103.43(8)
72.10(2)71.94(6)73.73(11)73.83(8)
72.215(19)71.94(6)73.93(11)73.84(7)
P–X–P100.42(9)97.3(2)92.6(5)93.0(3)
99.88(8)96.8(2)92.4(4)92.9(3)
CSD referenceThis workWEYJAL [33]KOKTEJ [37]LIQTAG [35]
Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content.

Share and Cite

MDPI and ACS Style

Wang, M.; Jourdain, I.; Knorr, M.; Strohmann, C.; Schmidt, A. Synthesis and Structural Characterization of Cobalt Complexes Ligated by N-Methyl(bis(diphenylphosphino)amine). Molbank 2025, 2025, M1967. https://doi.org/10.3390/M1967

AMA Style

Wang M, Jourdain I, Knorr M, Strohmann C, Schmidt A. Synthesis and Structural Characterization of Cobalt Complexes Ligated by N-Methyl(bis(diphenylphosphino)amine). Molbank. 2025; 2025(1):M1967. https://doi.org/10.3390/M1967

Chicago/Turabian Style

Wang, Mélaine, Isabelle Jourdain, Michael Knorr, Carsten Strohmann, and Annika Schmidt. 2025. "Synthesis and Structural Characterization of Cobalt Complexes Ligated by N-Methyl(bis(diphenylphosphino)amine)" Molbank 2025, no. 1: M1967. https://doi.org/10.3390/M1967

APA Style

Wang, M., Jourdain, I., Knorr, M., Strohmann, C., & Schmidt, A. (2025). Synthesis and Structural Characterization of Cobalt Complexes Ligated by N-Methyl(bis(diphenylphosphino)amine). Molbank, 2025(1), M1967. https://doi.org/10.3390/M1967

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

Article Metrics

Back to TopTop