Synthesis and structural characterization of zwitterionic oxorhenium(V) complexes with 2-hydroxypyridine

The novel zwitterionic complexes mer-[ReOCl3(Hhp)(PPh3)] and mer-[ReOBr3(Hhp)(PPh3)] (Hhp = 2-hydroxypyridine), whose X-ray crystal structures were determined, adopt a distorted octahedral coordination for the rhenium(V) center. The monodentate Hhp ligands coordinate in their protonated neutral form via their exocyclic oxygen atoms, which is novel for rhenium coordination compounds with this type of ligand.