Platinum Metals Rev., 1971, 15, (1), 25
Cubane-type Platinum Metal Complexes
Recent X-ray diffraction studies have shown that the two platinum metal complexes [(C2H5)3PtCl]4 and [(CO)3OsO]4 have cubane-type structure. The eight carbon atoms of cubane, C8H8, are situated at the corners of a cube. The structure of [(C2H5)3PtCl]4 is shown in the diagram to resemble cubane and that of the osmium compound is similar, the four osmium and four oxygen atoms being at alternate corners of a cube with the osmium atoms each bound to three terminal carbonyl groups.
In a joint communication Professor Sir Ronald Nyholm and Professor Mary R. Truter (University College, London) and C. W. Bradford (Johnson Matthey Research Laboratories) point out (Nature, 1970, 228, (5272, November 14), 648–651) that Pt(IV) and Os(II) are isoelectronic and that similar structures might be expected for other iso-electronic metals, e.g. W(O), Re(I) and Ir(III). In fact [(CO)2(NO)Mo(OH)]4 is formally of this type with one NO and two CO groups on each Mo(O) atom, OH being the negative group. The NO group is assumed to act as a unipositive radical. Furthermore Re(I) and Mn(I) form compounds [(CO)3M(SR)]4, which have structures with cubic symmetry. So far, however, no compounds of this type have been reported for the triad Co(III),Rh(III)and Ir(III).