Structural and Physical Investigations of Coordination Complexes Involving Pyridylethylenedithio–Tetrathiafulvalene Ligands Decorated with Cyanoethylsulfanyl and Cyanoethylselanyl Moieties

The two new ligands 4,5‐bis(2‐cyanoethylthio)‐4′,5′‐(4‐pyridylethylene‐1,2‐dithio)tetrathiafulvalene ( L 1 ) and 4,5‐bis(2‐cyanoethylseleno)‐4′,5′‐(4‐pyridylethylene‐1,2‐dithio)tetrathiafulvalene ( L 2 ) have been elaborated and used to synthesize five new coordination complexes of transition‐metal ions, namely, [Mn 2 (hfac) 4 ( L 1 ) 2 ] 2 ( 1 ; hfac – = 1,1,1,5,5,5‐hexafluoroacetylacetonate), [Cd(hfac) 2 ( L 1 ) 2 ] · 2CHCl 3 ( 2 ), [Cu(hfac) 2 ( L 1 ) 2 ] ( 3 ), [Co(hfac) 2 ( L 1 ) 2 ] · 2C 6 H 14 ( 4 ) and [Mn(hfac) 2 ( L 2 ) 2 ] · 2C 6 H 14 ( 5 ), which were characterized by single‐crystal X‐ray diffraction. Compounds 2 – 5 were identified as mononuclear complexes with different crystal packing depending on the nature of the metal centre. On the contrary, compound 1 was identified as a cyclic tetranuclear complex in which L 1 is coordinated to the Mn II ions through two different pyridyl and nitrile functionalizations. The photophysical properties of the ligands L 1 and L 2 were studied in solution and rationalized with time‐dependent density functional theory calculations.