Stepwise conversion of an osmium trimethylstannyl complex to a triiodostannyl complex and nucleophilic substitution reactions at the tin-iodine bonds

Treatment of the coordinatively unsaturated osmium complex Os(SnMe3)Cl(CO)(PPh3)(2) with sodium dimethyldithiocarbamate gives the coordinatively saturated complex Os(SnMe3)(eta(2)-S2CNMe2)(CO)(PPh3)(2) (1). Complex 1 reacts with excess SnI4 to give Os(SnMeI2)(eta(2)-S2CNMe2)(CO)(PPh3)(2) (3) in high yield. A redistribution reaction of 3 with an equimolar amount of 1 provides Os(SnMe2I)(eta(2)-S2CNMe2)(CO)(PPh3)(2) (2). The last remaining methyl group bonded to tin in 3 is removed by treatment with a slight excess of I-2, giving the triiodostannyl complex Os(SnI3)(eta(2)-S2CNMe2)(CO)(PPh3)(2) (4). Both 3 and 4 have been further derivatized by replacement of the halide groups on tin. Treatment of 3 with pyridinium tribromide gives Os(SnMeBr2)(eta(2)-S2CNMe2)(CO)(PPh3)(2) (5). Treatment of 3 with catechol provides Os(SnMe[1,2-O2C6H4])(eta(2)-S2CNMe2)(CO)(PPh3)(2) (6), while the similar reaction with 1,2-ethanedithiol gives Os(SnMe[1,2-S2C2H4])(eta(2)-S2CNMe2)(Co)(PPh3)(2) (7). Complex 4 undergoes reaction with an excess of KOH to give the trihydroxystannyl complex Os(Sn[OH](3))(eta(2)-S2CNMe2)(CO)(PPh3)(2) (8). Treatment of 4 with triethanolamine gives Os(Sn[OCH2CH2](3)N)(eta(2)S(2)CNMe(2))(CO)(PPh3)(2) (9), while reaction with nitrilotriacetic acid gives the metal-substituted stannatranone Os(Sn[OC(O)CH2](3)N)(eta(2)-S2CNMe2)(CO)(PPh3)(2) (10). The crystal structures of 1, 4, 5, 7, and 10 have been determined.