Dihydride versus Elongated Dihydrogen in [H₂Os(<i>κ</i>²-O₂CCH₃)L(PⁱPr₃)₂]⁺ Complexes: Influence of the L Ligand

The complex [OsH2(κ2-O2CCH3)(H2O)(PiPr3)2]BF4 (1) reacts with aniline, pyridine, and trimethyl phosphite. The reaction with aniline affords the dihydride derivative [OsH2(κ2-O2CCH3)(NH2Ph)(PiPr3)2]BF4 (2), while in the presence of pyridine a 7:1 equilibrium mixture of the dihydride [OsH2(κ2-O2CCH3)(py)(PiPr3)2]BF4 (3a) and the elongated dihydrogen-containing complex [Os(η2-Η2)(κ2-O2CCH3)(py)(PiPr3)2]BF4 (3b) is obtained. The reaction with trimethyl phosphite leads to the elongated dihydrogen complex [Os(η2-H2)(κ2-O2CCH3){P(OMe)3}(PiPr3)2]BF4 (4). The structures of 2 and 4 have been determined by X-ray diffraction analysis.