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Article

Synthesis, Structure, and Reactivity of Molybdenum– and Tungsten–Indane Complexes with Tris(pyrazolyl)borate Ligand

by
Masumi Itazaki
1,2,*,
Kunihisa Nouichi
2,
Ken-ichiro Ookuma
2,
Toshiyuki Moriuchi
1,2 and
Hiroshi Nakazawa
1,2,*
1
Department of Chemistry, Graduate School of Science, Osaka Metropolitan University, Sumiyoshi-ku, Osaka 558-8585, Japan
2
Department of Chemistry, Graduate School of Science, Osaka City University, Sumiyoshi-ku, Osaka 558-8585, Japan
*
Authors to whom correspondence should be addressed.
Molecules 2024, 29(4), 757; https://doi.org/10.3390/molecules29040757
Submission received: 26 December 2023 / Revised: 1 February 2024 / Accepted: 2 February 2024 / Published: 6 February 2024
(This article belongs to the Section Organometallic Chemistry)
Browse Figures
Versions Notes

Abstract

:
The reaction of molybdenum complexes with a tris(pyrazolyl)borate ligand (Et4N[TpMo(CO)3] and Et4N[Tp*Mo(CO)3] (Tp = hydridotris(pyrazolyl)borate, Tp* = hydridotris(3,5-dimethylpyrazolyl)borate)) and InBr3 at a 1:1 molar ratio afforded molybdenum–indane complexes (Et4N[TpMo(CO)3(InBr3)] 1 and Et4N[Tp*Mo(CO)3(InBr3)] 2). In addition, tungsten–indane complexes, Et4N[TpW(CO)3(InBr3)] 3 and Et4N[Tp*W(CO)3(InBr3)] 4, were obtained by the reaction of corresponding tungsten complexes. Complex 4 reacted with H2O to form the hydrido complex Tp*W(CO)3H, in which the W–In bond was cleaved. On the other hand, 4 reacted with three equiv. of AgNO3 to form Et4N[Tp*W(CO)3{In(ONO2)}] 5, in which three substituents on the In were exchanged while retaining the W–In dative bond. Complexes 1–5 were fully characterized using NMR measurements and elemental analyses, and the structures of 1–5 and Et4N[Tp*W(CO)3] were determined via X-ray crystallography. These are the first examples of mononuclear molybdenum– and tungsten–indane complexes with Mo–In and W–In dative bonds.

Graphical Abstract

1. Introduction

Common compounds with Group 13 elements as the central atom are designated as EX3 (E = B, Al, Ga, In, Tl) and are known as electron-deficient compounds. Therefore, for bonds formed between a Group 13 element and a transition metal (TM), a TM→E dative bond can be considered in addition to a TM–E covalent bond (for example, TM–EX2) (Figure 1 shows an example in which E = In) [1,2,3,4,5,6,7]. A normal bond between a TM and a ligand is formed by donating two electrons from the ligand to the TM. On the other hand, the TM→E dative bond is a bond created when two electrons are donated from the TM to E. This is called a Z-type interaction and it is a bond that is unique to Group 13 element compounds [8,9,10,11,12,13,14,15]. Although many compounds with TM–B bonds have been reported, there are not many reported examples of compounds with TM–In bonds, and among them, there are few examples of compounds with W–In bonds.
Figure 2 shows the complexes with W–In bonds that have been reported to date. In 1988, Norman et al. reported [In{CpW(CO)3}3], Na[{CpW(CO)3}2InCl2], and Na[{CpW(CO)3}InCl3] [16] as the first complexes with W–In bond(s). A crystal structure was reported in 2002 for [In{CpW(CO)3}3] by Scheer [17]. A thiocyanate indylene complex [{CpW(CO)3}2In(NCS)] was synthesized by Norman in 1995 [18]. Reger and Rheingold used a bulky In compound, Tp*InCl2·THF, to prepare the W–In complex [W(CO)5(InTp*)] [19]. A trihaloindate W complex [Ph4P]2[(CO)5W–InICl3] containing indium in a formal oxidation state of +I was obtained by the reaction of a reactive InI complex [(CO)5WInCl·THF] with an excess amount of [Ph4P]Cl [20]. We have also reported the pyridine-stabilized indylene complex [{Cp(CO)3W}2InCl(py)] [21]. It is reasonable that the W–In bond in the complexes listed above is a covalent bond. However, it is also possible to interpret it as a W→In dative bond. In fact, the nature of the W–In bond is not clearly stated in these papers.
Although there are no examples of structural analyses of complexes with clear W→In dative bonds, several examples of structural analyses of complexes with TM→In dative bonds have been reported for other transition metal complexes: one example for Pt [15], Pd [22], and Ru [23]; two examples for Co [24,25]; and three examples for Ni [26,27,28] and Rh [29,30,31].
In general, polynuclear complexes have several possibilities for how to allocate bonding electrons. The same is true for complexes with TM–In bonds. In other words, when a complex with a TM–In bond has a multinuclear structure, it becomes difficult to determine whether the TM–In bond is a dative bond or a covalent bond. In this study, we focus on complexes with clear TM–In dative bonds. To obtain a complex with a clear TM–In dative bond, it is necessary to prepare a mononuclear complex. Tp (hydridotris(pyrazolyl)borate) and Tp* (hydridotris(3,5-dimethylpyrazolyl)borate) have been widely used as six electron donor anionic ligands, like Cp (cyclopentadienyl) and Cp* (pentamethylcyclopentadienyl) ligands. However, since Tp and Tp* are bulkier than Cp and Cp*, complexes with Tp or Tp* as a ligand are less likely to form polynuclear complexes. Here, we selected Mo and W complexes with a Tp or Tp* ligand and examined their reaction with InBr3.

2. Results

2.1. Synthesis and Structure of Molybdenum–Indane Complexes with Tris(pyrazolyl)borate Ligand

Our reactions of Et4N[TpMo(CO)3] [32] and Et4N[Tp*Mo(CO)3] [32] with one equiv. of InBr3 afforded the molybdenum–indane complexes Et4N[TpMo(CO)3(InBr3)] 1 with a 92% yield and Et4N[Tp*Mo(CO)3(InBr3)] 2 with a 90% yield, respectively (Scheme 1). In the 1H NMR spectra of 1 and 2 in CD3CN, three CH signals (δ 6.30, 7.81, and 8.08) were observed for 1 and one CH signal (δ 5.92) and two CH3 signals (δ 2.30 and 2.41) were observed for 2. However, the BH proton was not observed because of a large nuclear quadrupole moment of B.
Single crystals of 1 and 2 were grown from a hot acetonitrile solution. The molecular structures of 1 and 2 were determined via X-ray crystallography. The ethyl groups of cationic parts were disordered, so the cationic parts were omitted for simplicity, and an ORTEP drawing of the anionic parts is depicted in Figure 3 with an atomic numbering scheme. Selected bond lengths (Å) and angles (°) are summarized in Table 1. To estimate the bond interaction of TM–E, the r value (the ratio of The M–E bond length to the sum of the TM and E covalent radii) has been used [25,33,34,35]. Thus, the r values are also listed in Table 1. Both 1 and 2 are seven-coordinated complexes. The Mo(0) center of 1 has a four-legged piano stool geometry, with one tridentate Tp ligand, three terminal CO ligands, and one InBr3 ligand. In contrast, the Mo(0) center of 2 is coordinated by one tridentate Tp* ligand, three terminal CO ligands, and one InBr3 ligand in a 3:3:1 face-capped octahedral arrangement. The capped octahedral structure is similar to the previously reported tin analog [Tp*Mo(CO)3(SnPh3)] [36]. The structural difference between the Tp and Tp* complexes is considered to come from the steric repulsion between the methyl groups on the Tp* ligand and the InBr3 ligand. The lengths of the Mo–In bond (2.8575(7) Å for 1, 2.8117(8) Å for 2) and In–Br3 bond (2.5476(8) Å, 2.5630(9) Å, and 2.5486(9) Å for 1, 2.5579(9) Å, 2.5408(10) Å, and 2.5467(10) Å for 2) are shorter than the sum of the Mo and In covalent radii (2.96 Å) and that of the In and Br covalent radii (2.68 Å), respectively [36]. The indium atoms of 1 and 2 have a pseudo-tetrahedral geometry. The Br–In–Br angles are 100.25(2)° to 105.87(3)° for 1 and 102.44(3)° to 103.85(4)° for 2. To the best of our knowledge, 1 and 2 are the first Mo–indane complexes to be prepared, isolated, and analyzed via their X-ray structure. The Mo–In bond length of 2 is shorter than that of 1, showing that a greater electron density is donated from Mo to In in 2 than in 1. The Mo–N bond lengths (an avg. of 2.251 Å for 1 vs. avg. 2.265 Å for Et4N[TpMo(CO)3] [37], and an 2.238 Å of for 2 vs. avg. 2.263 Å for Et4N[Tp*Mo(CO)3] [38]) do not change much before and after the coordination of the InBr3 ligand to the Mo center. In contrast, a comparison of the Mo–CO bond lengths led to an interesting finding: there was an avg. of 1.977 Å for 1 vs. avg. 1.925 Å for Et4N[TpMo(CO)3] [37], and an avg. of 1.981 Å for 2 vs. avg. 1.941 Å for Et4N[Tp*Mo(CO)3] [38]. In both cases of 1 and 2, the coordination of InBr3 to Mo lengthens the Mo–CO bonds. It is thought that the electron density of Mo decreases due to the coordination of the InBr3 ligand, weakening the π back-donation to the carbonyl ligands.

2.2. Synthesis and Structure of Tungsten–Indane Complexes with Tris(pyrazolyl)borate Ligand

Tungsten–indane complexes 3 and 4 were obtained with 92% and 90% yields by the reactions of Et4N[TpW(CO)3] [32] and Et4N[Tp*W(CO)3] [32] with one equiv. of InBr3, respectively (Scheme 2). The 1H NMR signals due to the Tp ligand of 3 were observed at δ 6.34, 7.84, and 8.21 in CD3CN and those due to the Tp* ligand of 4 were observed at δ 2.35, 2.42, and 5.97 in CD3CN. They were slightly downfield compared to the signals of the corresponding Mo–indane complexes (1 and 2).
Single crystals of 3, 4, and Et4N[Tp*W(CO)3] were obtained using the same methods as 1 and 2, and X-ray crystal analyses were conducted. The ethyl groups of the cationic parts were disordered, so the cationic parts were omitted for simplicity, and ORTEP drawings of the anionic parts are shown in Figure 4. The most characteristic parameters are summarized in Table 2. To the best of our knowledge, 3 and 4 are the first examples of the synthesis and structure of a tungsten–indane complex. The coordination environment around the metal center and the tendencies of the W–N bond lengths and the W–CO bond lengths of 3 and 4 are similar to those of 1 and 2, respectively. Although the Br–In–Br angles for 3 (99.87(2)° to 105.50(2)°) and 4 (102.63(4)° to 103.41(4)°) are similar to the corresponding 1 and 2, the r values of 3 (0.94) and 4 (0.93) are smaller than those of 1 (0.97) and 2 (0.95), suggesting that the M→In interaction is larger for W than Mo and for the Tp* complex than for the Tp complex. In other words, it is inferred that 4 has the strongest TM→InIII dative bond among 1–4.

2.3. Reactivity of Tungsten–Indane Complexes with Tp* Ligand

For indane complexes 1–4, which were prepared and isolated in this work, it was shown that the W–In dative bond of 4 was the strongest. Therefore, in order to investigate the possibility of this bond cleavage, the reaction of 4 with a Lewis base was conducted. In addition, in order to investigate whether the In–Br bond can be cleaved while retaining the W–In bond, the reactions of 4 with some Ag salts were examined.
Water was selected as a Lewis base to react with 4. Complex 4 was added to water and stirred at room temperature for 2 h, but no change occurred. However, when acetonitrile was added to this, 4 was converted into the hydrido complex (Tp*W(CO)3H) with a 64% yield (Scheme 3). Templeton et al. reported that the hydrido complex (Tp*W (CO)3H) was obtained in the reaction of Et4N[Tp*W(CO)3] with HCl [39]. Therefore, our observation shown in Scheme 3 can be explained in the following two ways. (i) InBr3 (a Lewis acid) forms a stronger bond with the Tp*W(CO)3 fragment than with H2O, so InBr3 does not dissociate from the W fragment in water, leading to no reaction. On the other hand, InBr3 forms a stronger bond with MeCN than Tp*W(CO)3, so when MeCN is added, 4 becomes [Tp*W(CO)3]− and MeCN–InBr3, and the generated [Tp*W(CO)3]− reacts with H2O to form Tp*W(CO)3H. (ii) Since [NEt4][Tp*W(CO)3(InBr3)] (4) is poorly soluble in water, no solid–liquid reaction occurred. To investigate the possibility of (ii), we synthesized K[Tp*W(CO)3(InBr3)], which shows better solubility in water than the NEt4 salt, and stirred this complex in water, confirming the formation of Tp*W(CO)3H. Therefore, the reason why 4 did not react with water is because of its extremely low solubility in water. The reactions mentioned above revealed that InBr3 inherently prefers to interact with H2O and MeCN rather than the Tp*W(CO)3 fragment.
Since Ag salts are widely used as halogen abstraction reagents, reactions of 4 with some Ag salts were examined. Complex 4 and three equiv. of Ag salt were stirred in MeCN at room temperature for 3 h in the dark. When AgClO3, AgOAc, AgOTf, and AgBF4 were used, complicated reactions occurred, and the product could not be identified. In the reaction of 4 with AgNO3, all Br atoms on the indium were replaced by three NO3 groups without breaking the W–In dative bond, and the corresponding complex Et4N[Tp*W(CO)3{In(ONO2)}] (5) was obtained with a 90% yield (Scheme 4). This method seems to be applicable to the synthesis of various transition metal–indane complexes.
Complex 5 was characterized via a single-crystal X-ray diffraction analysis. The cationic part was omitted for simplicity, an ORTEP drawing of the anionic part is shown in Figure 5, and selected bond lengths, angles, and r values are summarized in Table 3. The geometry about the W atom is a capped octahedral with the indium located at an axial position and a structure that is analogous to that of 4. Since In has a high electron-accepting ability, when it has an NO3 substituent, it often adopts an η2-type bonding mode and accepts three electrons rather than adopting an η1-type bonding mode and accepting one electron. The crystal structure of an In compound with three NO3 groups [In(4,4′-dmbipy)(η2-NO3)2(η1-NO3)(H2O)] (4,4′-dmbipy = 4,4′-dimethyl-2,2′-bipyridine) was reported, in which two NO3 are bonded in the η2-type bonding mode and one NO3 is bonded in the η1-type bonding mode to the In (η2-type In–O bond lengths: 2.291(12)–2.546(11) Å; η1-type In–O bond length: 2.203(8) Å) [40]. In the crystal structure of 5, in any three NO3 groups, one In–O length (2.176(2)–2.183(2) Å) is significantly shorter than the other two In–O lengths (2.623–2.744 Å). Thus, all of the three NO3 groups in the In form η1-type bonds (only one O atom makes a bond with In), and none of them form η2-type bonds (base-stabilized type). This can be considered to be a reflection of the Tp*W(CO)3 fragment donating a sufficient electron density to the In. Its r value of 5 (0.92) is the smallest among those of the complexes reported in this work.

3. Materials and Methods

3.1. General Considerations

All manipulations were carried out using standard Schlenk techniques under a dry nitrogen atmosphere. Molybdenum and tungsten complexes with Tp or Tp* ligands (Et4N[TpM(CO)3] and Et4N[Tp*M(CO)3] (M = Mo, W)) were prepared according to a method from the literature [32]. The other chemicals were commercially available. Solvents were purified employing a two-column solid-state purification system or were distilled from appropriate drying agents under N2. NMR spectra (1H and 13C) were recorded at ambient temperature on a JEOL JNM AL-400 spectrometer. 1H and 13C NMR data referred to residual peaks of solvent as an internal standard. Elemental analysis data were obtained with a Perkin–Elmer 2400 CHN elemental analyzer.

3.2. Syntheses

Et4N[TpMo(CO)3(InBr3)] (1). An acetonitrile solution (35 mL) containing Et4N[TpMo(CO)3] (310.1 mg, 0.59 mmol) and InBr3 (212.1 mg, 0.60 mmol) was stirred at room temperature. After 3 h, all volatile materials were removed under reduced pressure. The residual powder was washed with Et2O (15 mL × 4) and dried in vacuo to obtain 1 (478.0 mg, 92%) as a yellow-green powder. 1H NMR (400 MHz, CD3CN, ppm) spectra were as follows: δ 1.18 (m, 12H, CH2CH3), 3.14 (q, JHH = 7.2 Hz, 8H, CH2CH3), 6.30 (t, JHH = 2.4 Hz, 3H, 4-H), 7.81 (d, JHH = 2.4 Hz, 3H, 5-H), 8.08 (d, JHH = 2.4 Hz, 3H, 3-H). 13C NMR (100.4 MHz, CD3CN, ppm) spectra were as follows: δ 7.76 (s, CH2CH3), 53.05 (m, CH2CH3), 107.45 (s, 4-C), 137.65 (s, 5-C), 146.89 (s, 3-C), 223.94 (s, CO). Elemental analysis (%) calcd for C20H30BBr3N7O3InMo was as follows: C, 27.37; H, 3.44; N, 11.17. Found: C, 27.28; H, 3.35; N, 10.89%.
Et4N[Tp*Mo(CO)3(InBr3)] (2). In a procedure analogous to the outline above, Et4N[Tp*Mo(CO)3] (407.2 mg, 0.67 mmol) and InBr3 (244.6 mg, 0.69 mmol) obtained 2 (578.1 mg, 0.60 mmol, 90%) as a yellow powder. 1H NMR (400 MHz, CD3CN, ppm) spectra were as follows: δ 1.20 (m, 12H, CH2CH3), 2.30 (s, 9H, 5-Me), 2.41 (s, 9H, 3-Me), 3.14 (q, JHH = 7.2 Hz, 8H, CH2CH3), 5.92 (s, 3H, 4-H). 13C NMR (100.4 MHz, CD3CN, ppm) spectra were as follows: δ 7.71 (s, CH2CH3), 12.99 (s, 5-Me), 15.68 (s, 3-Me), 53.02 (s, CH2CH3), 107.73 (s, 4-C), 146.92 (s, 5-C), 152.69 (s, 3-C), 229.39 (s, CO). Elemental analysis (%) calcd for C26H42BBr3N7O3InMo was as follows: C, 32.46; H, 4.40; N, 10.19. Found: C, 32.54; H, 4.34; N, 10.04%.
Et4N[TpW(CO)3(InBr3)] (3). In a procedure analogous to the outline above, Et4N[TpW(CO)3] (359.4 mg, 0.59 mmol) and InBr3 (211.3 mg, 0.60 mmol) obtained 3 (567.9 mg, 0.59 mmol, 92%) as a yellow powder. 1H NMR (400 MHz, CD3CN, ppm) spectra were as follows: δ 1.13 (br, 12H, CH2CH3), 3.16 (q, JHH = 7.2 Hz, 8H, CH2CH3), 6.34 (s, 3H, 4-H), 7.84 (s, 3H, 5-H), 8.21 (s, 3H, 3-H). 13C NMR (100.4 MHz, CD3CN, ppm) spectra were as follows: δ 7.76 (s, CH2CH3), 53.05 (m, CH2CH3), 107.45 (s, 4-C), 137.65 (s, 5-C), 146.89 (s, 3-C), 223.94 (s, CO). Elemental analysis (%) calcd for C20H30BBr3N7O3InW was as follows: C, 24.88; H, 3.13; N, 10.15. Found: C, 24.61; H, 3.08; N, 9.78%.
Et4N[Tp*W(CO)3(InBr3)] (4). In a procedure analogous to the outline above, Et4N[Tp*W(CO)3] (134.4 mg, 0.19 mmol) and InBr3 (74.1 mg, 0.21 mmol) obtained 4 (183.2 mg, 0.18 mmol, 90%) as a yellow-green powder. 1H NMR (400 MHz, CD3CN, ppm) spectra were as follows: δ 1.20 (br, 12H, CH2CH3), 2.35 (s, 9H, 5-Me), 2.42 (s, 9H, 3-Me), 3.15 (q, JHH = 7.2 Hz, 8H, CH2CH3), 5.97 (s, 3H, 4-CH. 13C NMR (100.4 MHz, CD3CN, ppm) spectra were as follows: δ 5.90 (s, CH2CH3), 11.11 (s, 5-Me), 14.44 (s, 3-Me), 51.22 (m, CH2CH3), 106.14 (s, 4-C), 145.00 (s, 5-C), 151.05 (s, 3-C), 224.12 (s, CO). Elemental analysis (%) calcd for C26H42BBr3N7O3InW was as follows: C, 29.75; H, 4.03; N, 9.34. Found: C, 29.60; H, 3.96; N, 9.09%.
Et4N[Tp*W(CO)3{In(ONO2)3}] (5). An acetonitrile solution (30 mL) containing 4 (114.7 mg, 0.11 mmol) and AgNO3 (55.8 mg, 0.33 mmol) was stirred at room temperature under dark conditions. After 3 h, the formed solid product was collected by filtration and dried in vacuo to obtain 5 (98.1 mg, 0.10 mmol, 90%) as a dark-yellow powder. 1H NMR (400 MHz, CD3CN, ppm) spectra were as follows: δ 1.19 (br, 12H, CH2CH3), 2.28 (s, 9H, 5-Me), 2.43 (s, 9H, 3-Me), 3.14 (br, 8H, CH2CH3), 6.00 (s, 3H, 4-H). 13C NMR (100.4 MHz, CD3CN, ppm) spectra were as follows: δ 7.70 (s, CH2CH3), 13.02 (s, 5-Me), 15.92 (s, 3-Me), 53.03 (m, CH2CH3), 108.47 (s, 4-C), 147.45 (s, 5-C), 153.20 (s, 3-C), 224.41 (s, CO). Elemental analysis (%) calcd for C26H42BN10O12InW was as follows: C, 31.35; H, 4.25; N, 14.06. Found: C, 31.67; H, 4.25; N, 14.48%.

3.3. Crystallography

Crystallographic data and details of structure refinement parameters are summarized in Table 4 and Table 5. The single crystals 1–4 were grown from a hot acetonitrile solution. The single crystals of 5 were obtained using the slow diffusion method (acetonitrile/ether). Diffraction intensity data were collected with a Rigaku AFC11 with Saturn 724+ CCD diffractometer, and a semiempirical multi-scan absorption correction [41] was performed. The structures were solved using SIR97 [42] by subsequent difference Fourier syntheses and refined by full-matrix least-squares procedures on F2. All non-hydrogen atoms were refined with anisotropic displacement coefficients. Hydrogen atoms were treated as idealized contributions and refined in rigid group model. All software and sources of scattering factors are contained in the SHELXL-97 [43] and the SHELXL-2018/3 [44] program package. The Cambridge Crystallographic Data Centre (CCDC) deposition numbers of 1–5 and Et4N[Tp*W(CO)3] are included in Table 4 and Table 5.

4. Conclusions

We are able to show the first examples of the synthesis and structure of molybdenum– and tungsten–indane complexes (1–4). These complexes were obtained by the reactions of corresponding molybdenum and tungsten complexes with Tp or Tp* ligands with one equiv. of InBr3. The structural difference between the Tp complexes (1 and 3 having a four-legged piano stool geometry) and the Tp* complexes (2 and 4 having a 3:3:1 face-capped octahedral geometry) is considered to be derived from the steric repulsion between the methyl groups on the Tp* ligand and the InBr3 ligand. The reaction of 4 with H2O afforded the hydrido complex Tp*W(CO)3H as a result of the W–In bond cleavage. In contrast, the reaction of 4 with three equiv. of AgNO3 produced Et4N[Tp*W(CO)3{In(ONO2)}] 5, in which the In–Br bonds are cleaved while retaining the W–In dative bond. We believe that the findings obtained in this paper will contribute to our knowledge of the chemistry of transition metal–indane complexes.

Supplementary Materials

The following supporting information can be downloaded at: https://www.mdpi.com/article/10.3390/molecules29040757/s1. Figures S1–S10: NMR spectra of all new compounds, Figures S11–S16: Crystal packings of 1–5 and Et4N[Tp*W(CO)3].

Author Contributions

M.I., T.M. and H.N. conceived, designed, and wrote the paper. M.I., K.N. and K.-i.O. performed the experiments and analyzed the data. All authors have read and agreed to the published version of the manuscript.

Funding

This research received no external fundings.

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

The crystallographic data are available from the Cambridge Crystallographic Data Centre (CCDC). Other data not presented in Supplementary Materials are available upon request from the corresponding author.

Acknowledgments

We would like to thank R. Tanaka at Osaka Metropolitan University for their help with the single-crystal X-ray structure analysis. We also would like to thank the Analytical Center, Graduate School of Science, Osaka City University, and the Analytical Center, Graduate School of Science, Osaka Metropolitan University.

Conflicts of Interest

The authors declare no conflicts of interest.

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Molecules 29 00757 g001
Figure 1. Bond types between TM and indium compound: (i) dative bond; (ii) covalent bond.
Figure 1. Bond types between TM and indium compound: (i) dative bond; (ii) covalent bond.
Molecules 29 00757 g001
Molecules 29 00757 g002
Figure 2. The examples of previously reported W complexes with W–In bond(s) [16,17,18,19,20,21].
Figure 2. The examples of previously reported W complexes with W–In bond(s) [16,17,18,19,20,21].
Molecules 29 00757 g002
Molecules 29 00757 sch001
Scheme 1. Reactions of Et4N[TpMo(CO)3] and Et4N[Tp*Mo(CO)3] with 1 equiv. of InBr3.
Scheme 1. Reactions of Et4N[TpMo(CO)3] and Et4N[Tp*Mo(CO)3] with 1 equiv. of InBr3.
Molecules 29 00757 sch001
Molecules 29 00757 g003
Figure 3. ORTEP drawings of (i) the anionic part of Et4N[TpMo(CO)3(InBr3)] 1 and (ii) the anionic part of Et4N[Tp*Mo(CO)3(InBr3)] 2 in the crystal (30% thermal ellipsoidal plots). All hydrogen atoms (except for BH proton) are omitted for simplicity.
Figure 3. ORTEP drawings of (i) the anionic part of Et4N[TpMo(CO)3(InBr3)] 1 and (ii) the anionic part of Et4N[Tp*Mo(CO)3(InBr3)] 2 in the crystal (30% thermal ellipsoidal plots). All hydrogen atoms (except for BH proton) are omitted for simplicity.
Molecules 29 00757 g003
Molecules 29 00757 sch002
Scheme 2. Reactions of Et4N[TpW(CO)3] and Et4N[Tp*W(CO)3] with 1 equiv. of InBr3.
Scheme 2. Reactions of Et4N[TpW(CO)3] and Et4N[Tp*W(CO)3] with 1 equiv. of InBr3.
Molecules 29 00757 sch002
Molecules 29 00757 g004
Figure 4. ORTEP drawings of (i) the anionic part of Et4N[TpW(CO)3(InBr3)] 3, (ii) the anionic part of Et4N[Tp*W(CO)3(InBr3)] 4, and (iii) the anionic part of Et4N[Tp*W(CO)3] in the crystal (30% thermal ellipsoidal plots). All hydrogen atoms (except for BH proton) are omitted for simplicity.
Figure 4. ORTEP drawings of (i) the anionic part of Et4N[TpW(CO)3(InBr3)] 3, (ii) the anionic part of Et4N[Tp*W(CO)3(InBr3)] 4, and (iii) the anionic part of Et4N[Tp*W(CO)3] in the crystal (30% thermal ellipsoidal plots). All hydrogen atoms (except for BH proton) are omitted for simplicity.
Molecules 29 00757 g004
Molecules 29 00757 sch003
Scheme 3. Reaction of Et4N[Tp*W(CO)3] with H2O in acetonitrile.
Scheme 3. Reaction of Et4N[Tp*W(CO)3] with H2O in acetonitrile.
Molecules 29 00757 sch003
Molecules 29 00757 sch004
Scheme 4. Reaction of Et4N[Tp*W(CO)3] with 3 equiv. of AgNO3.
Scheme 4. Reaction of Et4N[Tp*W(CO)3] with 3 equiv. of AgNO3.
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Molecules 29 00757 g005
Figure 5. ORTEP drawing of anionic part of Et4N[Tp*W(CO)3{In(ONO2)3}] 5·CH3CN in the crystal (30% thermal ellipsoidal plots). The solvent for the crystallization (CH3CN), as well as all hydrogen atoms (except for BH proton) are omitted for simplicity.
Figure 5. ORTEP drawing of anionic part of Et4N[Tp*W(CO)3{In(ONO2)3}] 5·CH3CN in the crystal (30% thermal ellipsoidal plots). The solvent for the crystallization (CH3CN), as well as all hydrogen atoms (except for BH proton) are omitted for simplicity.
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Table 1. Selected bond lengths (Å) and angles (°) for 1 and 2.
Table 1. Selected bond lengths (Å) and angles (°) for 1 and 2.
12
Mo1–In12.8575(7)2.8117(8)
r a0.970.95
Mo1–C11.967(4)1.978(7)
Mo1–C21.977(5)1.983(7)
Mo1–C31.987(4)1.982(7)
Mo1–N22.238(3)2.230(5)
Mo1–N42.295(3)2.242(5)
Mo1–N62.219(3)2.241(6)
In1–Br12.5476(8)2.5579(9)
In1–Br22.5630(9)2.5408(10)
In1–Br32.5486(9)2.5467(10)
C1–Mo1–In1107.64(13)67.68(18)
C2–Mo1–In162.52(12)65.40(18)
C3–Mo1–In164.30(12)66.68(18)
a Ratio of the Mo–In bond length to the sum of Mo and In covalent radii [35].
Table 2. Selected bond lengths (Å) and angles (°) for 3, 4, and Et4N[Tp*W(CO)3].
Table 2. Selected bond lengths (Å) and angles (°) for 3, 4, and Et4N[Tp*W(CO)3].
34Et4N[Tp*W(CO)3]
W1–In12.8663(4)2.8287(7)
r a0.940.93
W1–C11.968(5)1.970(9)1.940(10)
W1–C21.975(5)1.970(8)1.933(11)
W1–C31.979(5)1.975(8)1.942(10)
W1–N22.229(4)2.236(6)2.258(8)
W1–N42.280(4)2.244(6)2.249(8)
W1–N62.206(4)2.225(6)2.241(9)
In1–Br12.5527(6)2.5453(11)
In1–Br22.5719(6)2.5456(11)
In1–Br32.5554(7)2.5608(11)
C1–W1–In1107.77(16)66.3(2)
C2–W1–In162.53(15)67.3(2)
C3–W1–In164.50(15)65.2(2)
a Ratio of the W–In bond length to the sum of W and In covalent radii [35].
Table 3. Selected bond lengths (Å) and angles (°) for 5.
Table 3. Selected bond lengths (Å) and angles (°) for 5.
5·CH3CN
W1–In12.7862(4)
r a0.92
W1–C11.980(3)
W1–C21.984(3)
W1–C31.990(3)
W1–N22.234(2)
W1–N42.235(2)
W1–N62.238(2)
In1–O42.183(2)
In1–O72.176(2)
In1–O102.180(2)
C1–W1–In167.32(8)
C2–W1–In166.38(8)
C3–W1–In166.26(9)
a Ratio of the W–In bond length to the sum of W and In covalent radii [35].
Table 4. Crystallographic data and details of structure refinement parameters of 1, 2, and Et4N[Tp*W(CO)3].
Table 4. Crystallographic data and details of structure refinement parameters of 1, 2, and Et4N[Tp*W(CO)3].
12Et4N[Tp*W(CO)3]
empirical formulaC20H30BBr3N7O3InMoC26H42BBr3N7O3InMoC26H42BN7O3W
formula weight877.81961.97695.32
T (K)200(2)200(2)200(2)
crystal systemmonoclinicmonoclinicorthorhombic
space groupP21/cP21/cPnma
a (Å)9.752(3)10.7918(15)17.9483(19)
b (Å)20.721(6)18.956(2)16.7315(16)
c (Å)15.341(5)18.011(2)9.8651(11)
β (°)102.664(4)103.763(3)
volume (Å3)3024.5(16)3578.8(8)2962.5(5)
Z444
ρcalcd (mg m−3)1.9281.7851.559
μ (mm−1)5.1744.3813.938
F(000)169618881400
crystal size (mm3)0.32 × 0.15 × 0.050.20 × 0.12 × 0.070.45 × 0.06 × 0.05
reflections collected24,06634,78829,203
R(int)6890 (0.0375)8146 (0.0494)4030 (0.0437)
R1 (I > 2σ(I)) a0.04140.06610.0352
wR2 (all data) b0.07720.12050.0919
goodness of fit1.0001.0361.247
CCDC deposition number2,320,4332,320,4362,321,243
a R1 = ∑||Fo| − |Fc||/∑|Fo|. b wR2 = [∑w(F2o − F2c)2/∑w(F2o)2]1/2.
Table 5. Crystallographic data and details of structure refinement parameters of 3–5.
Table 5. Crystallographic data and details of structure refinement parameters of 3–5.
345·CH3CN
empirical formulaC20H30BBr3N7O3InWC26H42BBr3N7O3InWC28H45BN11O12InW
formula weight965.721049.881037.23
T (K)200(2)203(2)200(2)
crystal systemmonoclinicmonoclinicmonoclinic
space groupP21/cP21/nP21/n
a (Å)9.7682(5)10.7972(14)10.432(2)
b (Å)20.6886(9)18.926(2)18.986(4)
c (Å)15.3167(8)18.664(3)19.975(4)
β (°)102.830(2)110.590(3)101.117(2)
volume (Å3)3018.1(3)3570.3(8)3882.3(13)
Z444
ρcalcd (mg m−3)2.1251.9531.775
μ (mm−1)8.5787.2593.626
F(000)182420162056
crystal size (mm3)0.10 × 0.10 × 0.060.18 × 0.10 × 0.060.32 × 0.10 × 0.10
reflections collected23,89335,17130,360
R(int)6860 (0.0327)8138 (0.0511)8813 (0.0260)
R1 (I > 2σ(I)) a0.03580.05680.0263
wR2 (all data) b0.06490.11150.0526
goodness of fit1.0001.0011.000
CCDC deposition number2,320,4372,320,4412,320,443
a R1 = ∑||Fo| − |Fc||/∑|Fo|. b wR2 = [∑w(F2o − F2c)2/∑w(F2o)2]1/2.
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Itazaki, M.; Nouichi, K.; Ookuma, K.-i.; Moriuchi, T.; Nakazawa, H. Synthesis, Structure, and Reactivity of Molybdenum– and Tungsten–Indane Complexes with Tris(pyrazolyl)borate Ligand. Molecules 2024, 29, 757. https://doi.org/10.3390/molecules29040757

AMA Style

Itazaki M, Nouichi K, Ookuma K-i, Moriuchi T, Nakazawa H. Synthesis, Structure, and Reactivity of Molybdenum– and Tungsten–Indane Complexes with Tris(pyrazolyl)borate Ligand. Molecules. 2024; 29(4):757. https://doi.org/10.3390/molecules29040757

Chicago/Turabian Style

Itazaki, Masumi, Kunihisa Nouichi, Ken-ichiro Ookuma, Toshiyuki Moriuchi, and Hiroshi Nakazawa. 2024. "Synthesis, Structure, and Reactivity of Molybdenum– and Tungsten–Indane Complexes with Tris(pyrazolyl)borate Ligand" Molecules 29, no. 4: 757. https://doi.org/10.3390/molecules29040757

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