Complexes of heteroscorpionate trispyrazolylborate ligands. Part XIII: Molybdenum complexes of hydrobis(5-methyl-3-phenylpyrazolyl)(3-methyl-5-phenylpyrazolyl)borate, hydrotris(3-(2-thienyl)-5-methylpyrazolyl)borate and tetranuclear molybdenum(V) com

摘要

The molybdenum complexes of hydrotrispyrazolylborate ligands were studied. Hydrotris(5-methyl-3-(2-thienyl)pyrazol-1-yl)borate (Tp(Th,Me)) was coordinated in eta(3) mode to molybdenum in [Et4N][Tp(Th,Me)Mo(CO)(3)] and Tp(Th,Me)Mo(CO)(3)(eta(3)-allyl) complexes in solid state as was determined crystallographically. The heteroscorpionate hydrobis(5-methyl-3-phenylpyrazol-1-yl)(3-methyl-5-phenyI pyrazol-1-yl)borate (Tp '') complexes: [Et4N][Tp '' Mo(CO)(3)] and Tp '' Mo(CO)(3)(eta(3)-allyl) were synthesized and their dynamic behavior and reactivity was studied and compared with standard [Et4N][T*Mo(CO)(3)] and Tp*Mo(CO)(3)(eta(3)-allyl) pair. All studied tricarbonyl complexes are reversibly oxidized at very low potentials, whereas the allyl compounds require much higher potentials for a generally irreversible oxidation to proceed. The oxidation products of Mo(0) and Mo(II) complexes with iodine and/or TBHP were characterized spectroscopically. The product of oxidation of Tp*Mo(CO)(3)I with oxygen was tetranuclear linear molybdenum(V) complex with terminal metal ions coordinated to Tp* ligands and inner molybdenum(V) ions surrounded exclusively by oxygen donors. (C) 2006 Elsevier Ltd. All rights reserved.