Structural and Physical Investigations of Coordination Complexes Involving Pyridylethylenedithio-Tetrathiafulvalene Ligands Decorated with Cyanoethylsulfanyl and Cyanoethylselanyl Moieties
Abstract
The two new ligands 4,5-bis(2-cyanoethylthio)-4',5'-(4-pyridylethylene-1,2-dithio)tetrathiafulvalene (L1) and 4,5-bis(2-cyanoethylseleno)-4',5'-(4-pyridylethylene-1,2-dithio)tetrathiafulvalene (L2) were elaborated and used to synthesize five new coordination complexes of transition-metal ions, namely, [Mn2(hfac)4(L1)2]2 (1; hfac- = 1,1,1,5,5,5-hexafluoroacetylacetonate), [Cd(hfac)2(L1)2]·2CHCl3 (2), [Cu(hfac)2(L1)2] (3), [Co(hfac)2(L1)2]·2C6H14 (4) and [Mn(hfac)2(L2)2]·2C6H14 (5), which were characterized by single-crystal x-ray diffraction. Compds. 2-5 were identified as mononuclear complexes with different crystal packing depending on the nature of the metal center. Compd. 1 was identified as a cyclic tetranuclear complex in which L1 is coordinated to the MnII ions through two different pyridyl and nitrile functionalizations. The photophys. properties of the ligands L1 and L2 were studied in soln. and rationalized with time-dependent d. functional theory calcns.