Synthesis and Hydride Transfer Reactions of Cobalt and Nickel Hydride Complexes to BX3 Compounds
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- 作者：Michael T. Mock ; Robert G. Potter ; Molly J. O鈥橦agan ; Donald M. Camaioni ; William G. Dougherty ; W. Scott Kassel ; Daniel L. DuBois
- 刊名：Inorganic Chemistry
- 出版年：2011
- 出版时间：December 5, 2011
- 年：2011
- 卷：50
- 期：23
- 页码：11914-11928
- 全文大小：578K
- 年卷期：v.50,no.23(December 5, 2011)
- ISSN：1520-510X
文摘
Hydrides of numerous transition metal complexes can be generated by the heterolytic cleavage of H2 gas such that they offer alternatives to using main group hydrides in the regeneration of ammonia borane, a compound that has been intensely studied for hydrogen storage applications. Previously, we reported that HRh(dmpe)2 (dmpe = 1,2-bis(dimethylphosphinoethane)) was capable of reducing a variety of BX3 compounds having a hydride affinity (HA) greater than or equal to the HA of BEt3. This study examines the reactivity of less expensive cobalt and nickel hydride complexes, HCo(dmpe)2 and [HNi(dmpe)2]+, to form B鈥揌 bonds. The hydride donor abilities (螖GH鈥?/sup>掳) of HCo(dmpe)2 and [HNi(dmpe)2]+ were positioned on a previously established scale in acetonitrile that is cross-referenced with calculated HAs of BX3 compounds. The collective data guided our selection of BX3 compounds to investigate and aided our analysis of factors that determine favorability of hydride transfer. HCo(dmpe)2 was observed to transfer H鈥?/sup> to BX3 compounds with X = H, OC6F5, and SPh. The reaction with B(SPh)3 is accompanied by the formation of dmpe-(BH3)2 and dmpe-(BH2(SPh))2 products that follow from a reduction of multiple B鈥揝Ph bonds and a loss of dmpe ligands from cobalt. Reactions between HCo(dmpe)2 and B(SPh)3 in the presence of triethylamine result in the formation of Et3N鈥揃H2SPh and Et3N鈥揃H3 with no loss of a dmpe ligand. Reactions of the cationic complex [HNi(dmpe)2]+ with B(SPh)3 under analogous conditions give Et3N鈥揃H2SPh as the final product along with the nickel鈥搕hiolate complex [Ni(dmpe)2(SPh)]+. The synthesis and characterization of HCo(dedpe)2 (dedpe = Et2PCH2CH2PPh2) from H2 and a base is also discussed, including the formation of an uncommon trans dihydride species, trans-[(H)2Co(dedpe)2][BF4].