LAUSR

The influence of chelate ligands in the formation and nature of bis(dihydrogen) units of OsH4 complexes has been studied. The classical trihydride OsH3{κ2-C,N-(C6H4-py)}(PiPr3)2 (1) reacts with HBF4·OEt2 to give the Kubas-type dihydrogen–elongated dihydrogen derivative [Os{κ2-C,N-(C6H4-py)}(η2-H2)2(PiPr3)2]BF4 (2), as a result of the protonation of one of the hydride ligands. Triflate (OTf) displaces the Kubas-type dihydrogen and elongates the elongated dihydrogen ligand, which is converted into a compressed dihydride. Thus, the addition of 1 equiv of HOTf to 1 leads to Os(H···H){κ2-C,N-(C6H4-py)}(OTf)(PiPr3)2 (3). Similar to [OTf]−, acetone reacts with 2 to afford the related compressed dihydride [Os(H···H){κ2-C,N-(C6H4-py)}(κ1-OCMe2)(PiPr3)2]BF4 (4), whereas acetonitrile leads to a 1:8 mixture of the monohydride [OsH(CH3CN)3(PiPr3)2]BF4 (5) and the trihydride [OsH3(CH3CN)2(PiPr3)2]BF4 (6). Reactions of 2 with toluene and p-xylene yield the half-sandwich derivatives [Os{κ2-C,N-(C6H4-py)}(η6-toluene)(PiPr...