Syntheses, reactions, and structures of osmium(II) distannyl complexes, LnOs–SnMe2SnR3 (R = Me, Ph), from reaction between LnOs–SnClMe2 and either LiSnMe3 or KSnPh3

Reaction between Os(SnClMe2)(κ2-S2CNMe2)(CO)(PPh3)2 and either LiSnMe3 or KSnPh3 produces the distannyl complexes, Os(SnMe2SnMe3)(κ2-S2CNMe2)(CO)(PPh3)2 (1) or Os(SnMe2SnPh3)(κ2-S2CNMe2)(CO)(PPh3)2 (3), respectively. Similarly, reaction between Os(SnClMe2)Cl(CO)2(PPh3)2 (6) and KSnPh3 produces the distannyl complex, Os(SnMe2SnPh3)Cl(CO)2(PPh3)2 (7). In the 119Sn NMR spectra of these stable osmium(II) distannyl complexes both the α-Sn and β-Sn atoms show well-resolved 119Sn–119Sn and 119Sn–117Sn coupling. Each of these three distannyl complexes can be selectively functionalised at the α-Sn atom by reaction with SnCl2Me2 giving Os(SnClMeSnMe3)(κ2-S2CNMe2)(CO)(PPh3)2 (2), Os(SnClMeSnPh3)(κ2-S2CNMe2)(CO)(PPh3)2 (4), and Os(SnClMeSnPh3)Cl(CO)2(PPh3)2 (8), respectively. Treatment of compounds 3 or 7 with iodine also cleaves one α-methyl group, selectively, to give Os(SnIMeSnPh3)(κ2-S2CNMe2)(CO)(PPh3)2 (5), or Os(SnIMeSnPh3)Cl(CO)2(PPh3)2 (9). Crystal structures for complexes 3 and 7 have been determined.