NEW FUNCTIONALIZED TETRATHIAFULVALENES - X-RAY CRYSTAL-STRUCTURES ANDPHYSICOCHEMICAL PROPERTIES OF TTF-C(O)NME(2) AND TTF-C(O)-O-C4H9 - A JOINT EXPERIMENTAL AND THEORETICAL-STUDY

The synthesis of the new mono- and di-functionalized tetrathiafulvalen e (TTF) derivatives 4, 5 and 12-15 is reported. Compounds 4 and 5 have been studied in detail: their single crystal X-ray structures are rep orted and theoretical calculations at both semiempirical and ab initio levels have been performed. The TTF moiety in the crystal of 4 is fol ded, whereas in the crystal of 5 it is essentially planar. In the crys tal structure of 4 the molecules related via an inversion centre form close dimers which pack in a severely distorted kappa-arrangement. Mol ecules of 5 assemble into uniform stacks with TTF moieties overlapping the side chains of adjacent molecules. Calculated geometries are in g ood agreement with the X-ray data, and the distortion from planarity i n the crystal of 4 can be explained by nonbonding interactions between the amide substituent and the TTF rings of adjacent molecules. Eviden ce for intramolecular charge-transfer from the TTF ring to the electro n-withdrawing amide and ester substituents of 4 and 5, respectively, i s provided by UV-VIS spectroscopy in solution, analysis of the bond le ngths in the crystal structure, and by theoretical calculations.