NEW CATECHOLATO OXORHENIUM(V) COMPLEXES

The complexes [ReO(L)(PPh3)2X] [H2L = catechol (H2cat), tetrachlorocatechol (H2tccat) or tetrabromocatechol (H2tbcat); X = Cl or I], [NBun4][ReO(L')(tccat)2](L' = OPPh3, MeOH or pyridine), [NBun4][ReO(OPPh3)(tbcat)2] and [ReO(PPh3)(L")2]I [HL" = tropolone (2-hydroxycyclohepta-2,4,6-trien-1-one) or maltol (3-hydroxy-2-methylpyran-4-one)] have been isolated and their infrared, Raman, P-31 and C-13 NMR spectra are reported. The X-ray crystal structures of [NBun4][ReO(OPPh3)-(tccat)2] 1 and [NBun4][ReO(MeOH)(tccat)2] 2 are presented. In both molecules the co-ordination geometry about Re is very similar, being distorted octahedral with the catecholato ligands folded away from a very strongly bonded oxo ligand [1.576(8) angstrom in 1 and 1.653(11) angstrom in 2] with weakly bound OPPh3 and MeOH ligands in the trans positions.