Syntheses, structures and reactivities of [Os6Pd(CO)18(bipy)] and [{(bipy)Pd}2Os3(CO)12]. Crystal and molecular structures of [{(bipy)Pd}2(m-H)(m-CO)][H3Os4(CO)12] and [(C4H9)4N]2[Pd2I6]

Abstract

The complex [(bipy)Pd(CO(2)Me)(2)] reacts with [Os-3(CO)(10)(NCMe)(2)] in a 1:1 molar ratio to give [Os6Pd(CO)(18)(bipy)] (1) with a moderate yield, and the crystal structure of 1 is presented. Complex 1 is separately treated with an excess of iodine and tetra-n-butylammonium iodide, giving [Os-6(CO)(18)] and [((n)Bu)(4)N](2)[Pd2I6] (2) respectively. Complex 2 is characterized by X-ray crystallography. The cyclic voltammogram of 1 reveals an irreversible oxidation at a potential of around 0.75 V and no reduction wave is observed. On the contrary, the reaction of [(bipy)Pd(CO(2)Me)(2)] with [H2Os3(CO)(10)] in a 1:2 molar ratio gives [{(bipy)Pd}Os-2(3)(CO)(12)] (3) with a 25\% yield. The X-ray crystallographic study of 3 reveals a stacking situation of the molecules along the c axis. Treatment of 3 with an excess of chloride salt leads to the formation of the cationic species [{(bipy)Pd}(2)(mu-H)(mu-CO)](+) (4) the [H3Os4(CO)(12)](-) salt of which is isolated. Again, a stacking of the dinuclear cations is observed from the X-ray structural analysis of 4.