Phosphinoborane-induced fragmentation of the unsaturated hydride H2Re2(CO)8: X-ray structure of HRe(CO)4(κB,P-Ph2PCH2CH2BR2) (where BR2 = 9-borabicyclo[3.3.1]nonanyl) and DFT Evaluation of hydride versus CO coordination by the ancillary borane

Huang, Shih-Huang Huang; Wang, Xiaoping; Richmond, Michael G.

doi:10.1016/j.jorganchem.2011.11.020

Cited by 9 publications

(4 citation statements)

References 37 publications

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“…Such tautomeric behavior has been the subject of great interest, owing to a desire to develop new bifunctional reagents for H – , H + , and H • transfer with Cp*(M n –H)/Cp*H(M n –2 ) complexes being an example . In the realm of ligand design, significant progress has also been made with the aim of developing bifunctional H – delivery reagents using tethered borohydride and other organic-based donors.…”

Section: Introductionmentioning

confidence: 99%

Wrapping Rhodium in a Borane Canopy: Implications for Hydride Formation and Transfer

2021

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The unique reactivity of metal hydrides has encouraged considerable advances in both synthesis and catalysis. In this arena, ligand optimization has played a significant role, wherein metal−ligand cooperativity can be employed to guide reactivity. Of the organometallic hydride donors, rhodium(I) bis(diphosphine) compounds are known to be among the strongest with hydricity (ΔG H − ) values near that of conventionally used reducing agents: e.g., trialkyl-substituted borohydrides (ΔG H − ≈ 26 kcal mol −1 for [HBEt 3 ]  ). Herein, we assess the thermodynamic site of hydride transfer using a rhodium(I) compound bearing a boron-rich diphosphine ligand: [Rh I (P 2 B Cy 4 ) 2 ]BPh 4 (P 2 B Cy 4 = 1,2-bis(di(3-dicyclohexylboraneyl)propylphosphino)ethane). The divergent reactivity of [Rh I (P 2 B Cy 4 ) 2 ]BPh 4 and its all-alkyl relative [Rh I (dnppe) 2 ]BPh 4 (dnppe = 1,2-bis(di-n-propylphosphino)ethane) toward hydride donors is underscored, where for the former the preferred site of hydride transfer is the ligand scaffold and not rhodium. This result is contrasted by facile generation of [Rh I (dnppe) 2 (H)]a species having a value of ΔG H − ostensibly similar to that of [Rh I (P 2 B Cy 4 ) 2 (H)] (which is not observed), underscoring a noninnocent and cooperative role for the boron-rich secondary coordination sphere of the P 2 B Cy 4 scaffold. The use of the ligand to serve as a hydride source was accordingly examined.

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Section: Introductionmentioning

confidence: 99%

Wrapping Rhodium in a Borane Canopy: Implications for Hydride Formation and Transfer

2021

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“…Reaction of the ambiphilic phosphinoborane Ph 2 PCH 2 CH 2 BR 2 (BR 2 = 9-borabicyclo[3,3,1]nonanyl) with the unsaturated dimer [H 2 Re 2 (CO) 8 ] led to the formation of [HRe(CO) 4 (κ 2 B , P -Ph 2 PCH 2 CH 2 BR 2 )] ( 30 ) as the sole product (Scheme ). From X-ray crystallography and DFT calculations, it has been established that the borane in the ambiphilic ligand coordinates to the Re–H bond to form a 3c–2e Re–H–B bond.…”

Section: Introductionmentioning

confidence: 99%

Main Group Lewis Acid-Mediated Transformations of Transition-Metal Hydride Complexes

2016

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This Review highlights stoichiometric reactions and elementary steps of catalytic reactions involving cooperative participation of transition-metal hydrides and main group Lewis acids. Included are reactions where the transition-metal hydride acts as a reactant as well as transformations that form the metal hydride as a product. This Review is divided by reaction type, illustrating the diverse roles that Lewis acids can play in mediating transformations involving transition-metal hydrides as either reactants or products. We begin with a discussion of reactions where metal hydrides form direct adducts with Lewis acids, elaborating the structure and dynamics of the products of these reactions. The bulk of this Review focuses on reactions where the transition metal and Lewis acid act in cooperation, and includes sections on carbonyl reduction, H2 activation, and hydride elimination reactions, all of which can be promoted by Lewis acids. Also included is a section on Lewis acid-base secondary coordination sphere interactions, which can influence the reactivity of hydrides. Work from the past 50 years is included, but the majority of this Review focuses on research from the past decade, with the intent of showcasing the rapid emergence of this field and the potential for further development into the future.

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“…The structure shows that two P atoms (P1 and P2) are bent down [N1–W1–P1 = 103.21(7)° and N1–W1–P2 = 102.34(6)°] and displaced by approximately 0.67 and 0.68 Å from the average equatorial plane created by the CO ligands and the W center to facilitate a tridentate chelation involving P–W coordination and coordination of the B atom to the hydridic H atom leading to a strong (C 8 H 14 )B–H interaction in the secondary coordination sphere. The measured B1–H1 distance of 1.38(3) Å is much shorter than those in trans ‐ 4b [1.60(6) Å] and the analogous rhenium phosphanylborane complex HRe(CO) 4 [κ B,P ‐Ph 2 PCH 2 CH 2 B(C 8 H 14 )] [1.46 Å],8 which indicates that the interaction between these two atomic centers is much stronger. Three strained chelate rings (one four‐membered and two six‐membered rings) are formed around the W center resulting from three fold coordination of the phosphanylborane ligand.…”

Section: Resultsmentioning

confidence: 93%

Coordination Properties of Multidentate Phosphanylborane Ligands in Tungsten Nitrosyl Complexes

et al. 2013

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The ambiphilic and small‐bite‐angle diphosphanylborane ligands Ph2PCH(PPh2)CH2B(C8H14) (2) and Ph2PCH2CH[B(C8H14)]PPh2 (3) containing the Lewis acidic 9‐boranorbornyl group B(C8H14) have been prepared in one step by regioselective anti‐Markovnikov hydroborations of 1,1‐bis(diphenylphosphanyl)ethylene and 1,2‐bis(diphenylphosphanyl)ethylene with 9‐borabicyclo[3.3.1]nonane (9‐BBN) under relatively drastic reaction condition. The coordination properties of Ph2PCH2CH2B(C8H14) (1) and the newly prepared 2 and 3 towards the tungsten nitrosyl fragment {WNO}6 have been studied structurally and spectroscopically. Herein, we report the cis and trans tungsten nitrosyl complexes cis‐[W(CO)2(1)2(NO)(Cl)] (cis‐4a), cis‐[W(CO)2(1)2(NO)(H)] (cis‐4b), trans‐[W(CO)2(1)2(NO)(Cl)] (trans‐4a), trans‐[W(CO)2(1)2(NO)(H)] (trans‐4b), cis‐[W(CO)2(2)(NO)(Cl)] (cis‐5a), cis‐[W(CO)2(2)(NO)(H)] (cis‐5b), cis‐[W(CO)2(3)(NO)(Cl)] (cis‐6a), cis‐[W(CO)2(3)(NO)(H)] (cis‐6b), which were readily obtained from straightforward ligand‐substitution reactions of the tungsten carbonyl nitrosyl precursor [W(NO)(CO)4(ClAlCl3)] in tetrahydrofuran. The crystal structures of the tungsten chloride complexes cis‐4a, trans‐4a, and cis‐5a revealed that the trialkyl boron centers are free pendants in the secondary coordination spheres, whereas in the hydride complexes trans‐4b, cis‐5b, and cis‐6b the hydride ligand trans to the nitrosyl ligand is σ coordinated to the tethered B(C8H14) group and form three‐center, two‐electron (3c–2e) W–H–B bonds, which were observed in their crystal structures. The authenticity of the 3c–2e W–H–B bond in the tungsten hydride complex cis‐5b was further checked by a DFT structural optimization and natural bond order (NBO) analysis.

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Phosphinoborane-induced fragmentation of the unsaturated hydride H2Re2(CO)8: X-ray structure of HRe(CO)4(κB,P-Ph2PCH2CH2BR2) (where BR2 = 9-borabicyclo[3.3.1]nonanyl) and DFT Evaluation of hydride versus CO coordination by the ancillary borane

Cited by 9 publications

References 37 publications

Wrapping Rhodium in a Borane Canopy: Implications for Hydride Formation and Transfer

Wrapping Rhodium in a Borane Canopy: Implications for Hydride Formation and Transfer

Main Group Lewis Acid-Mediated Transformations of Transition-Metal Hydride Complexes

Coordination Properties of Multidentate Phosphanylborane Ligands in Tungsten Nitrosyl Complexes

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