Dioxime and pyridine-2-aldoxime complexes of image

We present the synthesis and characterization of a series of dioxime and pyridine-2-aldoxime complexes of rhenium(I) tricarbonyl. Complexes of the formula ReL(CO)3XReL(CO)3X (L = dioxime (1,2), dimethylglyoxime (3,4), diphenylglyoxime (5,6), 1,2-cyclohexanedione dioxime (7,8); X = Cl, Br) can be readily generated by reaction of the neutral ligand with Re(CO)5XRe(CO)5X (X = Cl, Br) or [Re(CO)3(H2O)3]Br[Re(CO)3(H2O)3]Br. A similar set of pyridine-2-aldoximes of the formula ReL(CO)3XReL(CO)3X (L = pyridine-2-aldoxime (9,10), 2-pyridylamidoxime (11,12); X = Cl, Br) can also be synthesized in an analogous fashion. Compounds 1–6, 9 and 12 were characterized by single crystal X-ray diffraction. These complexes all exhibit bidentate coordination of the oxime ligands as well as the expected facial arrangement of carbonyls around the metals with the halides completing the octahedral coordination spheres. The oxime groups remain protonated in all of the complexes. Compounds 1–12 all exhibit absorptions in the UV–Vis region resulting from MLCT transitions.