The effect of the "inert" counteranions in the deprotonation of the dihydrogen complex trans-[FeH(eta 2-H2)(dppe)2]+: kinetic and theoretical studies.
Kinetic studies indicate that trans-[FeH(H2)(dppe)2]+ reacts with an excess of NEt3 to form cis-[FeH2(dppe)2] in a single kinetic step. The second-order rate constant is strongly affected by the presence of added salts, an acceleration being observed with BF4- and PF6- salts and a deceleration with BPh4-. Theoretical calculations indicate that the role of the accelerating anions consists of the formation of ion pairs that provide a more effective reaction pathway for deprotonation. However, for the ion pair with the bulky BPh4- anion, steric crowding in the proximities of the dihydrogen ligand hinders the approach of the base, and the reaction is decelerated.
Basallote
Manuel G
MG
Departamento de Ciencia de los Materiales e Ingeniería Metalúrgica y Química Inorgánica, Facultad de Ciencias, Universidad de Cádiz, Apartado 40, Puerto Real, 11510 Cádiz, Spain. manuel.basallote@uca.es
Besora
Maria
M
Durán
Joaquín
J
Fernández-Trujillo
M Jesús
MJ
Lledós
Agustí
A
Máñez
M Angeles
MA
Maseras
Feliu
F