Neutral and cationic ruthenium hydrotris(pyrazolyl)borate derivatives containing bulky monodentate phosphines. Crystal structures of [RuTp(H2O)(PPri2Me)2][CF3SO3]·EtOH and [RuTp(N2)(PEt3)2][BPh4]
Abstract
The complexes [RuTp(Cl)(PPri2Me)2] 1 and [RuTp(Cl)(PEt3)2] 2 were prepared by thermal displacement of PPh3 from [RuTp(Cl)(PPh3)2] by the corresponding phosphine. A series of cationic complexes of the type [RuTp(L)(PR3)2]+ (L = H2O, N2 or CNBut; PR3 = PPri2Me or PEt3) was obtained by chloride abstraction from 1 or 2 in the presence of L. As consequence of the steric crowding, one of the PPri2Me ligands in 1 is labile, and it was readily replaced by neutral molecules such as MeCN or CNBut to yield the neutral complexes [RuTp(Cl)L(PPri2Me)] (L = MeCN or CNBut). The monohydrides [RuTp(H)(PPri2Me)2] and [RuTp(H)(PEt3)2] were obtained by treatment of 1 or 2 with NaBH4 in MeOH. Protonation of these monohydrides led to the cationic dihydrogen complexes [RuTp(H2)(PPri2Me)2]+ and [RuTp(H2)(PEt3)2]+ which were isolated as [BPh4]– salts, and characterized by determination of their (T1)min and 1JHD coupling constants in the corresponding isotopomers. The neutral hydride(dihydrogen) complex [RuTp(H)(H2)(PPri2Me)], which resulted from the reaction of [RuTp(Cl)(MeCN)(PPri2Me)] with NaBH4 in MeOH, was characterized in analogous fashion. The crystal structures of the complexes [RuTp(H2O)(PPri2Me)2][CF3SO3]·EtOH and [RuTp(N2)(PEt3)2][BPh4] were determined.