TTF-fused heteroleptic bis(phthalocyaninato) europium double-decker complexes. Synthesis, spectroscopic, and electrochemical properties.

Mixed cyclic tetramerization of 5,6-dicyano-2-(4,5-bis(amylthio)-1,3-dithio-2-ylidene)-benzo[ d ]-1,3-dithiole and 1,2-dicyanobenzene with half-sandwich complex Eu(Pc)(acac) as template in the presence of DBU in refluxing n -pentanol led to the formation and isolation of a series of unprecedented tetrathiafulvalene(TTF)-fused heteroleptic bis(phthalocyaninato) europium double-deckers Eu(Pc)[Pc(TTF) n ] (n = 1–4) ( 1 , 2- cis , 2- trans , 3 , and 4 ). Electronic absorption spectroscopic results reveal the effect of fusing TTF onto the phthalocyanine chromophore of double-decker on the electronic structure of the target compounds. ESR together with the IR and electronic absorption spectra disclose the existence of unpaired electron in the newly prepared heteroleptic complexes. In particular, in addition to the Pc-chromophore based one-electron redox processes, one-electron, two-electron, three-electron, and four electron oxidation processes were clearly revealed by the electrochemical technique for the one-TTF, two-TTF, three-TTF, and four-TTF moiety-fused double-decker 1 , 2- cis and 2- trans , 3 , and 4 , respectively, indicating the significant influence of the TTF moieties fused to the double-decker electronic structure. In particular, theoretical calculations over 0 and 4 in combination with the electronic absorption spectroscopy reveal the significant influence of the fused-TTF units to the electronic structure. [ABSTRACT FROM AUTHOR]