Dihydrogen Bonding in Complex (PP3)RuH(η1-BH4) Featuring Two Proton-Accepting Hydride Sites: Experimental and Theoretical Studies

详细信息    查看全文

• 作者：Natalia V. Belkova ; Ekaterina V. Bakhmutova-Albert ; Evgenii I. Gutsul ; Vladimir I. Bakhmutov ; Igor E. Golub ; Oleg A. Filippov ; Lina M. Epstein ; Maurizio Peruzzini ; Andrea Rossin ; Fabrizio Zanobini ; Elena S. Shubina
• 刊名：Inorganic Chemistry
• 出版年：2014
• 出版时间：January 21, 2014
• 年：2014
• 卷：53
• 期：2
• 页码：1080-1090
• 全文大小：529K
• ISSN：1520-510X

文摘

Combining variable-temperature infrared and NMR spectroscopic studies with quantum-chemical calculations (density functional theory (DFT) and natural bond orbital) allowed us to address the problem of competition between MH (M = transition metal) and BH hydrogens as proton-accepting sites in dihydrogen bond (DHB) and to unravel the mechanism of proton transfer to complex (PP₃)RuH(畏¹-BH₄) (1, PP₃ = 魏⁴-P(CH₂CH₂PPh₂)₃). Interaction of complex 1 with CH₃OH, fluorinated alcohols of variable acid strength [CH₂FCH₂OH, CF₃CH₂OH, (CF₃)₂CHOH (HFIP), (CF₃)₃COH], and CF₃COOH leads to the medium-strength DHB complexes involving BH bonds (3鈥? kcal/mol), whereas DHB complexes with RuH were not observed experimentally. The two proton-transfer pathways were considered in DFT/M06 calculations. The first one goes via more favorable bifurcate complexes to BH_term and high activation barriers (38.2 and 28.4 kcal/mol in case of HFIP) and leads directly to the thermodynamic product [(PP₃)RuH_eq(H₂)]⁺[OR]^{鈭?/sup>. The second pathway starts from the less-favorable complex with RuH ligand but shows a lower activation barrier (23.5 kcal/mol for HFIP) and eventually leads to the final product via the isomerization of intermediate [(PP₃)RuH_ax(H₂)]+[OR]鈭?/sup>. The B鈥揌_br bond breaking is the common key step of all pathways investigated.}