Preparation and reactivity of stannyl and germyl complexes of cobalt

Trichlorostannyl complex Co(SnCl3)(CO)2(PPh3)2 (1) was prepared by allowing the chloro compound CoCl(CO)2(PPh3)2 to react with SnCl2·2H2O. Instead, treatment of the iodo complex CoI(CO)2[PPh(OEt)2]2 with SnCl2·2H2O afforded a mixture of Co(SnCl2I)(CO)2[PPh(OEt)2]2 (2a) and Co(SnCl3)(CO)2[PPh(OEt)2]2 (2b) derivatives. Trichlorogermyl complexes Co(GeCl3)(CO)2L2 (3, 4) [L = PPh3, PPh(OEt)2] were prepared by allowing halo compounds CoX(CO)2L2 (X = Cl, I) to react with GeCl2·dioxane. Treatment of trihalostannyl complexes Co(SnCl2X)(CO)2L2 (1, 2) (X = Cl, I) with NaBH4 in ethanol yielded tin trihydrido derivatives Co(SnH3)(CO)2L2 (5, 6). Instead, reaction of Co(SnCl2X)(CO)2[PPh(OEt)2]2 (2) with LiAlH4 in THF yielded the hydrido CoH(CO)2[PPh(OEt)2]2 (7). Trimethylstannyl Co(SnMe3)(CO)2L2 (8, 9) and trialkynylstannyl derivatives Co[Sn(CCPh)3](CO)2L2 (10, 11) were prepared by allowing trihalostannyl compounds Co(SnCl2X)(CO)2L2 (1, 2) to react with MgBrMe and with Li+(PhCC)−, respectively, in THF. The complexes were characterised by spectroscopy (IR and 1H, 31P, 13C, 119Sn NMR) and by X-ray crystal structure determination of Co(SnCl2X)(CO)2[PPh(OEt)2]2 (2) and Co(GeCl3)(CO)2[PPh(OEt)2]2 (4).

Graphical abstractReaction of halocomplexes CoX(CO)2L2 with SnCl2·2H2O and GeCl2·dioxane leading to trihalostannyl Co(SnCl2X)(CO)2L2 and trichlorogermyl derivatives Co(GeCl3)(CO)2L2 is described. The preparation of trihydridostannyl complexes Co(SnH3)(CO)2L2 and organostannyl derivatives Co(SnMe3)(CO)2L2 and Co[Sn(C≡CPh)3](CO)2L2 is also reported.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Synthesis of trihalo- stannyl and germyl complexes of cobalt. ► Treatment with NaBH4 affords trihydridostannyl derivatives. ► Trimethylstannyl and trialkynylstannyl complexes of Co(I) were also prepared.