Preparation of trihydridostannyl complexes of rhenium stabilised by isocyanide ligands

Abstract

Mixed-ligand complexes [ReBr(CO) 2(CNR) n L 3− n ] ( 1– 4) [R = 4-CH 3OC 6H 4, 4-CH 3C 6H 4, C(CH 3) 3; L = P(OEt) 3, PPh(OEt) 2; n = 1, 2] were prepared by allowing carbonyl compounds [ReBr(CO) 4L] and [ReBr(CO) 3L 2] to react with an excess of isocyanide. Treatment of these bromocomplexes [ReBr(CO) 2(CNR) n L 3− n ] with SnCl 2 · 2H 2O yielded the trichlorostannyl derivatives [Re(SnCl 3)(CO) 2(CNR) n L 3− n ] ( 5–8). Trihydridestannyl complexes [Re(SnH 3)(CO) 2(CNR) n L 3− n ] ( 9–12) were prepared by allowing trichlorostannyl compounds 5– 8 to react with NaBH 4 in ethanol. The trimethylstannyl derivative [Re(SnMe 3)(CO) 2(CNC 6H 4-4-CH 3){PPh(OEt) 2} 2] ( 13b) was also prepared by treating [Re(SnCl 3)(CO) 2(CNC 6H 4-4-CH 3){PPh(OEt) 2} 2] with an excess of MgBrMe in diethylether. Reaction of the tin trihydride complexes [Re(SnH 3)(CO) 2(CNR) n L 3− n ] ( 9– 12) with CO 2 (1 atm) led to dinuclear OH-bridging bis(formate) derivatives [Re{Sn(OC(H) O) 2(μ-OH)}(CO) 2(CNR) n L 3− n ] 2 ( 14, 15). The complexes were characterised spectroscopically (IR, 1H, 31P, 13C, 119Sn NMR) and by X-ray crystal structure determination of [Re(SnH 3)(CO) 2{CNC(CH 3) 3}{PPh(OEt) 2} 2] ( 10b).