Oxidation of fac-[M(CO) 3(NCMe) 3] (M=Mo or W) with I 2Cl 6. Reactions of the seven-coordinate complex [WCl(ClICl)(CO) 3(NCMe) 2

Abstract

Reaction of fac-[Mo(CO) 3(NCMe) 3] (prepared in situ) with I 2Cl 6 resulted in a large amount of effervescence and the formation of a dark red–brown solution, and a yellow precipitate. Both the yellow precipitate and the orange solid resulting from work-up of the dark red–brown solution were found to be the MoMo bonded non-carbonyl containing tetracationic complex [Mo 2(NCMe) 8][Cl] 2[ClICl] 2 ( 1). Oxidation of fac-[W(CO) 3(NCMe) 3] (prepared in situ) with I 2Cl 6 gave the seven-coordinate complex [WCl(ClICl)(CO) 3(NCMe) 2] ( 2). Treatment of 2 with an equimolar amount of L {L=PPh 3 [stirred for 1 min], AsPh 3 [stirred for 3 min] and SbPh 3 [stirred for 5 min]} in CH 2Cl 2 at room temperature gave [WCl(ClICl)(CO) 3(NCMe)L] ( 3– 5). Reaction of [WCl(ClICl)(CO) 3(NCMe) 2] with an equimolar amount of L {L=PPh 3, AsPh 3 and SbPh 3} in CH 2Cl 2 at room temperature for 24 h gave the chloro-bridged complexes [{W(μ-Cl)(ClICl)(CO) 3L} 2] ( 6– 8). Reaction of [WCl(ClICl)(CO) 3(NCMe) 2] with 2 equiv. of RC 2R (R=Me or Ph) in CH 2Cl 2 at room temperature gave the bis(alkyne) complexes [WCl(ClICl)(CO)(NCMe)(η 2-RC 2R) 2] ( 9 and 10). The reactions of [WCl(ClICl)(CO)(NCMe)(η 2-PhC 2Ph) 2] with 1 equiv. of L ∧L {L ∧L=Ph 2P(CH 2) n PPh 2 ( n=1–4, 6) or 2,2′-bipyridine} in CH 2Cl 2 at room temperature afforded the complexes [WCl(ClICl)(CO)(L ∧L)(η 2-PhC 2Ph)] ( 11– 16). Treatment of [WCl(ClICl)(CO)(NCMe)(η 2-RC 2R) 2] (R=Me or Ph) with 2 equiv. of L ∧L {L ∧L=Ph 2P(CH 2) n PPh 2 ( n=1–4, 6) in CH 2Cl 2 at room temperature afforded the dicationic complexes [W(CO)(L ∧L) 2(η 2-RC 2R)][Cl][ClICl]·CH 2Cl 2 ( 17– 26). All the new complexes described in this paper were characterised by elemental analysis, IR and 1H NMR spectroscopy.