| Abstract
| - Novel π-extended tetrathiafulvalene (TTF) derivatives (12a−c, 13a−c, 15a−c) in which the two1,3-dithiole units are connected through a naphthalene spacer have been prepared in high yieldsby Wittig−Horner olefination reaction from dialkoxy-substituted diformylnaphthalenes (11a,b, 14)and differently substituted phosphonate esters (10a−c). The electrochemical study revealed a similarbehavior for the novel electron donor molecules (12a−c, 13a−c, 15a−c) regardless of the positionof the 1,3-dithiole rings on the naphthalene core. The extended donors undergo an efficientelectrooxidation process affording new oligomeric extended TTF species which exhibit loweroxidation potential values than their precursor donors. EPR experiments confirm the presence ofthe cation radical derived from the oligomeric TTF vinylogues and support an ECE process. Thestructural study has been carried out by X-ray analysis of 12a and semiempirical PM3 calculationsand reveals a distorted geometry from the planarity with the naphthalene moiety forming an angleof ∼35° with the thiafulvalene rings. A good agreement was found between the experimental andcalculated values, thus validating the PM3 method. The chemical oxidation of the synthesized donors(12a−c, 13a−c, 15a−c) with strong electron acceptors give rise to charge transfer complexes (CTC)which were characterized by UV−vis, FTIR, and EPR spectroscopy.
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