Low-temperature IR and NMR studies of the interaction of group 8 metal dihydrides with alcohols.
The reactions of the octahedral dihydrido complexes [MH(2)(PP(3))] [M=Fe, Ru, Os; PP(3)=P(CH(2)CH(2)PPh(2))(3)] with a variety of weak ROH acids have been studied by IR and NMR methods in either CH(2)Cl(2) or THF in the temperature range from 190 to 290 K. This study has allowed the determination of the spectral and thermodynamic properties associated with the formation of dihydrogen bonds (DHB) between the terminal hydrides and the OH group. Both the DHB enthalpy values and the hydride basicity factors (E(j)) have been found to increase in the order Fe < Ru < Os. The proton transfer process, leading to the DHB complexes, and eventually to eta(2)-H(2) products, has been found to depend on the acidic strength of the alcohol as well as the nature of the solvent. Low temperature IR and NMR techniques have been used to trace the complete energy profile of the proton transfer process involving the osmium complex [OsH(2)(PP(3))] with trifluoroethanol.
Gutsul
Evgenii I
EI
AN Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences Vavilov str 28, 119 991 Moscow, Russia. epst@ineos.ac.ru
Belkova
Natalia V
NV
Sverdlov
Maria S
MS
Epstein
Lina M
LM
Shubina
Elena S
ES
Bakhmutov
Vladimir I
VI
Gribanova
Tatiana N
TN
Minyaev
Ruslan M
RM
Bianchini
Claudio
C
Peruzzini
Maurizio
M
Zanobini
Fabrizio
F