Análogos tiofénicos del TCNQ: Estudio teórico de las propiedades estructurales y electrónicas.

by Milián Medina, Begoña

SUMMARY The present Doctoral Thesis deals with the theoretical study of the structural and electronic properties of TCNE, TCNQ, thiophene-TCNQ, and its derivatives. Such derivatives result from the modification of the thiophenic spacer in thiophene-TCNQ through different strategies like the extension of the p-system of the thiophene ring by fusion of aromatic rings, leading to the isotianaphthene-TCNQ and its pyrazine analogue molecules, or by introduction of vinylic groups; the linear extension of the quinonoid structure through repetition of the central thiophene moiety, leading to quinonoid dimers, trimers and tetramers, or through annelation of thiophene and benzene rings; and finally, The introduction of electron donor and electron acceptor groups in the same molecule, giving rise to the push-pull systems. The molecules studied have been chosen because of their interest in the field of electroactive molecular materials. Density functional theory, in its time-independent and time-dependent versions (DFT and TDDFT, respectively), has been extensively used. The quality and suitability of the DFT procedures have been calibrated by using more accurate methodological approaches (CCSD, CCSD(T), and CASSCF/CASPT2). The quantum-chemical calculations have made possible to rationalize the structural and electronic properties of the different families of thiophenic analogues of TCNQ, in their neutral and reduced states, paying special attention to the influence that the structural modifications have on the electron acceptor properties (electron affinity and redox properties) of these compounds.