Syntheses, Characterization, and Properties of Rhenium(I) Tricarbonyl Complexes with Tetrathiafulvalene-Fused Phenanthroline Ligands

A series of tetrathiafulvalene-annulated phenanthroline ligands, 4′,5′-dimethyldithiotetrathiafulvenyl[4,5-f][1,10]phenanthroline (L1), 4′,5′-ethylenedithiotetrathiafulvenyl[4,5-f][1,10]phenanthroline (L2), and 4′,5′-bis(methyloxycarbonyl)dithiotetrathiafulvenyl[4,5-f][1,10]phenanthroline (L3), have been prepared by a facile and efficient synthetic procedure under mild conditions. Further coordination reactions of these ligands with Re(CO)5Cl afford new rhenium tricarbonyl complexes, Re(CO)3Cl(L) (L = L1, 3a; L = L2, 3b; L = L3, 3c), respectively. X-ray crystal structure determinations on 3a,c reveal that the ligands are nearly planar and they show a unique packing mode in the solid state. The electrochemical and spectroscopic behavior of these compounds (L1−L3, 3a−c) has been studied. The results suggest that the redox-active tetrathiafulvalene-phenanthroline ligands are useful for new metal complexes.