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 (L-1), 4',5'-ethylenedithiotetrathiafulvenyl[4,5-f] [1,10] phenanthroline (L-2), and 4',5'-bis(methyloxycarbonyl)dithiotetrathiafulvenyl[4,5-f][1,10]phenanthroline (L-3), have been prepared by a facile and efficient synthetic procedure under mild conditions. Further coordination reactions of these ligands with Re (CO)(5) Cl afford new rhenium tricarbonyl complexes, Re(CO)(3)Cl(L) (L = L-1, 3a; L = L-2, 3b; L = L-3, 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 (L-1-L-3, 3a-c) has been studied. The results suggest that the redox-active tetrathiafulvalene-phenanthroline ligands are useful for new metal complexes.