BROMINATION OF MOLYBDENUM CARBONYLS REVISITED - OXO COMPLEXES AND ROUTES TO NEW MATERIALS CHEMISTRY

The use of in situ [{MoBr(mu-Br)(CO)(4)}(2)] led to considerably improved preparations of [MoBr2(CO)(3)(PPh(3))(2)] for which the rate of decarbonylation to [MoBr2(CO)(2)(PPh(3))(2)] is greatly increased by refluxing under reduced pressure (15-20 mmHg). Attempts to prepare [MoBr2- (CO)(2){P(C6H11)(3)}(2)] by Br-2 addition to cis- or trans-[Mo(CO)(4){P(C6H11)(3)}(2)] led to [HP(C6H11)(3)][Mo-(=0)Br(4)L] [L = OP(C6H11)(3) or H2O]. The OP(C6H11)(3) complex maybe used as a catalyst for the epoxidation of cyclohexene or for the addition of singlet oxygen to alpha-terpinene (1-isopropyl-4-methylcyclohexa-1, 3-diene). The species [HP(C6H11)(3)] [Mo(=0)Br-4{OP(C6H11)(3)}] was adsorbed onto sodium montmorillonite in a new type of reaction for sodium montmorillonite involving multiple abstractions of NaBr from the complex anion. In solution [HP(C6H11)(3)][Mo(=0)Br-4{OP(C6H11)(3)}] also decomposes to crystalline [Mo(=0)(2)Br-2{OP(C6H11)(3)}(2)] which is monoclinic, space group C2/c [a = 27.15(5), b = 8.486(8), c = 18.49(2) Angstrom, beta = 110.94(7)degrees].