Reactivity of hydroxo complexes of palladiumj(II) towards nitriles: formation of carboxamide and imino ether derivatives of palladium(II)

摘要

The binuclear hydroxo complexes [Pd_2(C, N)_2(#mu#-OH)_2] [C, N = 2-(dimethylaminomethyl)phenyl (dmba) or 2-(phenylazo)phenyl (az)] have been prepared by addition of 2equivalents of NBu_4OH to the corresponding di-#mu#-acetate complexes in acetone. The reactions of both hydroxo complexes with a number of nitriles, RCN, led to the formation of the carboxamide complexes [Pd_2(C, N)_2(#mu#-NHC(R)O)_2] (R = Me, Ph or CH_2=CH) as well as the succinonitrile derivatives [(C, N) Pd}NHC(O)CH_2CH_2C(O)NH} Pd(C, N)]. The complexes [Pd_2(C, N)_2-(-NHC(Me)O)_2]~(2-) reacted with nitriles in methanol or ethanol to give the imino ether complexes [Pd(C_6F_5)_4(#mu#-OH_2]~(2-) reacted with nitriles in methanol or ethanol to give the imino ether complexes [Pd(C_6F_5)_2{NH=C(OR')R}_2] (R = Ph, R' = Me or Et; R = Me, R' = Me or Et) which in acetone solution are present as mixtures of EE, EZ and ZZ isomers. Similar reactions with 2-cyanopyridine and succinonitrile gave [Pd(C_6F_5)_2{NC_5H_4C(OR')NH-2}] and [Pd(C_6_5)_2{NHC(OR')CH_2CH_2NH(OR')}] (R' = Me or Et) and the reaction with 2-cyanopyridine in acetone yielded [Pd(C_6_5)_2{NC_5H_4C(=O)NH-2}]. The crystal structures of [Pd_2(dmba)_2-(#mu#NHC(Ph)O)_2] and [Pd(C_6_5)_2{NH=C(OMe)Me}_2] have been determined by single-crystal X-ray diffraction.