Bromination of molybdenum carbonyls revisited: oxo complexes and routes to new materials chemistry

The use of in situMoBr (µ-Br) (CO) 42 led to considerably improved preparations of MoBr2 (CO) 3 (PPh3) 2 for which the rate of decarbonylation to MoBr2 (CO) 2 (PPh3) 2 is greatly increased by refluxing under reduced pressure (15–20 mmHg). Attempts to prepare MoBr2 (CO) 2P (C6H11) 32 by Br2 addition to cis- or trans-Mo (CO) 4P (C6H11) 32 led to HP (C6H11) 3Mo (O) Br4LL = OP (C6H11) 3 or H2O. The OP (C6H11) 3 complex may be used as a catalyst for the epoxidation of cyclohexene or for the addition of singlet oxygen to α-terpinene (1-isopropyl-4-methylcyclohexa-1, 3-diene). The species HP (C6H11) 3Mo (O) Br4OP (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) 3Mo (O) Br4OP (C6H11) 3 also decomposes to crystalline Mo (O) 2Br2OP (C6H11) 32 which is monoclinic, space group C2/ca= 27. 15 (5), b= 8. 486 (8), c= 18. 49 (2) Å, β= 110. 94 (7) °.