Measurement of the Hydride Donor Abilities of [HM(diphosphine)2]+ Complexes (M = Ni, Pt) by Heterolytic Activation of Hydrogen
摘要:
[M(diphosphine)(2)](2+) complexes (where M = Ni and Pt) react with hydrogen in the presence of bases to form the corresponding hydrides, [HM(diphosphine)(2)](+). In seven cases, equilibria have been observed from which the hydride donor ability (DeltaGdegrees(H-)) of the hydrides can be calculated. For six of these complexes, the DeltaGdegrees(H-) values calculated using heterolytic activation of hydrogen are compared with those based on thermodynamic cycles using pK(a) measurements and electrochemical half-wave potentials. The agreement between these two methods is good (within 1 kcal/mol). The reactivity of the various [M(diphosphine)(2)](2+) complexes toward hydrogen parallels their measured hydride acceptor abilities.
Measurement of the Hydride Donor Abilities of [HM(diphosphine)2]+ Complexes (M = Ni, Pt) by Heterolytic Activation of Hydrogen
摘要:
[M(diphosphine)(2)](2+) complexes (where M = Ni and Pt) react with hydrogen in the presence of bases to form the corresponding hydrides, [HM(diphosphine)(2)](+). In seven cases, equilibria have been observed from which the hydride donor ability (DeltaGdegrees(H-)) of the hydrides can be calculated. For six of these complexes, the DeltaGdegrees(H-) values calculated using heterolytic activation of hydrogen are compared with those based on thermodynamic cycles using pK(a) measurements and electrochemical half-wave potentials. The agreement between these two methods is good (within 1 kcal/mol). The reactivity of the various [M(diphosphine)(2)](2+) complexes toward hydrogen parallels their measured hydride acceptor abilities.
Solvent influence on the thermodynamics for hydride transfer from bis(diphosphine) complexes of nickel
作者:Samantha J. Connelly Robinson、Christopher M. Zall、Deanna L. Miller、John C. Linehan、Aaron M. Appel
DOI:10.1039/c6dt00309e
日期:——
metal hydride and CO2 to produce formate. Because the hydricities of these species do not vary consistently between solvents, reactions that are thermodynamically unfavourable in one solvent can be favourable in others. The hydricity of a water-soluble, bis-phosphine nickel hydride complex was compared to the hydricity of formate in water and in acetonitrile. Formate is a better hydride donor than [HNi(dmpe)2]+