Reactions of carbon dioxide with the electron-rich polyhydride complex [Mo(dmpe)2H4]

Fong, Lawrence K.; Fox, James R.; Cooper, N. John

doi:10.1021/om00145a002

Cited by 27 publications

(19 citation statements)

References 1 publication

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“…The IR spectrum of 9 revealed two intense bands at 1611 and 1320 cm -1 for the formate ligand, in accordance with other η 1 -formate complexes reported in the literature. [49,50] The structure of 9 was finally confirmed by an X-ray diffraction analysis ( Figure 4). The molybdenum centre adopts a pseudooctahedral geometry, with the NBEt 3 moiety and the η 1 -formato ligand trans to each other.…”

Section: Hydride Transfer Reactions Of Mo(h)(n)(depe) 2 (7) and Transmentioning

confidence: 82%

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Hydride Transfer Reactivity of Mo(L)(H)(depe)₂ (L = N, NBEt₃)

et al. 2006

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Starting from Mo(N 2 ) 2 (depe) 2 (1), the nitrido complex Mo(N)-(N 3 )(depe) 2 (2) was obtained by the reaction of 1 with Me 3 -SiN 3 . Subsequent reaction of 2 with HCl in CH 3 OH afforded the cationic imido chloride 3, which could be converted into the nitrido chloride 4 with sodium bis(trimethylsilyl)amide. From 3 and 4 the hydrido complexes of the type Mo(H)(L)-(depe) 2 [L = N (7), NBEt 3 (8)] were obtained by the reaction with the hydride reagents LiBH 4 and NaHBEt 3 . The hydridic character of the L n M-H bond of 8 was determined by DQCC measurements (bond ionicity i = 81 %). Hydride reactivity studies were carried out on 7 and 8; however, only 8 underwent hydride transfer reactions. 8 reacted with 4,4Ј-dichlorobenzophenone and acetophenone to afford the correspond-

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Section: Hydride Transfer Reactions Of Mo(h)(n)(depe) 2 (7) and Transmentioning

confidence: 82%

“…The structure revealed an Mo-O bond length of 2.214(2) Å. [18,50,51] The Mo-N and N-B bond lengths of 1.713(3) Å and 1.609(5) Å, respectively, are similar to those of 10 and 14.…”

Section: Hydride Transfer Reactions Of Mo(h)(n)(depe) 2 (7) and Transmentioning

confidence: 86%

Hydride Transfer Reactivity of Mo(L)(H)(depe)₂ (L = N, NBEt₃)

et al. 2006

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“…Collecting 1 H-coupled 13 C data confirmed that the resonance centered at 54.9 ppm is a doublet (J CH = 171.12 Hz), indicating it is bound to a single hydrogen atom (see Figure S14 of the Supporting Information). 39 Attempts to locate a Mo−H resonance by COSY or NOESY NMR spectroscopy were unsuccessful. The 31 P NMR spectrum of this product featured two sets of doublets at 46.93 and 57.94 ppm (J PP = 97.2 Hz), further supporting static left-to-right Ph2PPr PDI inequivalence.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Conversion of Carbon Dioxide to Methanol Using a C–H Activated Bis(imino)pyridine Molybdenum Hydroboration Catalyst

2015

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Using a multistep synthetic pathway, a bis(imino)pyridine (or pyridine diimine, PDI) molybdenum catalyst for the selective conversion of carbon dioxide into methanol has been developed. Starting from ((Ph2PPr)PDI)Mo(CO), I2 addition afforded [((Ph2PPr)PDI)MoI(CO)][I], which features a seven-coordinate Mo(II) center. Heating this complex to 100 °C under vacuum resulted in CO loss and the formation of [((Ph2PPr)PDI)MoI][I]. Reduction of [((Ph2PPr)PDI)MoI][I] in the presence of excess K/Hg yielded (κ(6)-P,N,N,N,C,P-(Ph2PPr)PDI)MoH following methylene group C-H activation at the α-position of one PDI imine substituent. The addition of CO2 to (κ(6)-P,N,N,N,C,P-(Ph2PPr)PDI)MoH resulted in facile insertion to generate the respective η(1)-formate complex, (κ(6)-P,N,N,N,C,P-(Ph2PPr)PDI)Mo(OCOH). When low pressures of CO2 were added to solutions of (κ(6)-P,N,N,N,C,P-(Ph2PPr)PDI)MoH containing pinacolborane, the selective formation of H3COBPin and O(BPin)2 was observed along with precatalyst regeneration. When HBPin was limited, H2C(OBPin)2 was observed as an intermediate and (κ(6)-P,N,N,N,C,P-(Ph2PPr)PDI)Mo(OCOH) remained present throughout CO2 reduction. The hydroboration of CO2 to H3COBPin was optimized and 97% HBPin utilization by 0.1 mol % (κ(6)-P,N,N,N,C,P-(Ph2PPr)PDI)MoH was demonstrated over 8 h at 90 °C, resulting in a methoxide formation turnover frequency (TOF) of 40.4 h(-1) (B-H utilization TOF = 121.2 h(-1)). Hydrolysis of the products and distillation at 65 °C allowed for MeOH isolation. The mechanism of (κ(6)-P,N,N,N,C,P-(Ph2PPr)PDI)MoH mediated CO2 hydroboration is presented in the context of these experimental observations. Notably, (κ(6)-P,N,N,N,C,P-(Ph2PPr)PDI)MoH is the first Mo hydroboration catalyst capable of converting CO2 to MeOH, and the importance of this study as it relates to previously described catalysts is discussed.

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“…Therefore, it is required to find highly reactive metal catalysts. The investigations of the reaction between carbon dioxide and metal compounds, as transition elements, e.g., Ni [5][6][7][8][9], Pd [10,11], Pt [22], Co [12,55], Rh [13,14,22,34], Ir [15][16][17][18], Fe [19][20][21]34,53], Ru [22][23][24][25][26]34,53], Mn [27][28][29], Re [27,[30][31][32][33][34], Cr [35], Mo [35][36][37][38][39], W [35,[38][39][40][41], V …”

Section: Introductionmentioning

confidence: 99%