Double oxidative addition of tin(IV) halides to platinum(II): Complexes with Pt-Sn and Pt-Sn-Pt linkages

The electron-rich organoplatinum complex [PtMe2(bu(2)bpy)], 1, bu(2)bpy = 4 ,4 ' -di-tert-butyl-2,2 ' -bipyridine, undergoes easy oxidative addition of a Sn-Cl bond of PhnSnCl4-n to give the corresponding stannylplatinum(IV) c omplexes [PtClMe2(SnPhnCl3-n)(bu(2)bpy)] 2, n = 0; 3, n = 1; 4, n = 2; 5, n = 3. Further reaction of 1 with 2 or 3 can occur to give the mu -stannylen e complexes [{PtClMe2(bu(2)bpy)}(2)(mu -SnPhnCl2-n)], 6, n = 0; 7, n = 1, t he first time that mu -stannylene complexes have been prepared by oxidative addition of Sn-Cl bonds. In all cases, the oxidative additions of Sn-Cl bo nds to platinum(II) occurred with trans stereochemistry. The products are c haracterized by NMR spectroscopy and, in most cases, by X-ray structure det erminations. Trends in coupling constants [especially (1)J(PtSn)] and bond distances and angles give insight into structure and bonding in the series of complexes. Complex 2 was cocrystallized with the organotin compound [Me2 SnCl2.Me2SnO](2). The oxidative addition of GeCl4 to complex 1 occurs with cis-stereochemistry to give [PtClMe2(GeCl3)(bu(2)bpy)], which does not reac t with more complex 1 to give a mu -germylene complex.