Hybrid inorganic-organic, organic charge transfer, and radical based compounds with chalcofulvalene donors and organic acceptors

Abstract

The primary focus of this dissertation is the electrochemical preparation of radical cation salts utilizing the donor o-4,4’-dimethyltetrathiafulvalene (o-Me2TTF) and spherical, tetrahedral, octahedral, bimetallic, cyanometallate, and polyoxometallate anions. Other donors, such as tetramethyl(tetraselenafulvalene) (TMTSF), tetramethyl(tetrathiafulvalene) (TMTTF), bis(ethylenedithio)tetrathiafulvalene (BEDTTTF or ET), and bis(propylenedithio)tetrathiafulvalene (BPDT-TTF or PT) also found use in the preparation of salts in the course of this study. X-ray structural characterization of these salts revealed stacking between donor molecules containing significant S•••S interactions in the solid state. Various salts were subjected to either conductivity or molecular magnetism measurements in order to determine the level of itinerant electron density and magnetic contribution from paramagnetic charge compensating anions. In order to expand the library of TTF-containing hybrid materials prepared through metathesis, salts of other tetrathiafulvalenium radicals have also been prepared and characterized crystallographically and by select spectroscopic methods. In an effort to gain further information on formation of organic charge transfer complexes, TTF was combined with nitrofluorenone family of acceptors as well as the organocyanide acceptors HAT-(CN)6 (HAT-(CN)6 = 1,4,5,8,9,12-hexaazatriphenylenehexacarbonitrile) and TCNB (TCNB = 1,2,4,5-tetracyanobenzene). The complexes were characterized using X-ray crystallography, infrared spectroscopy, and molecular magnetism. All of these techniques showed that all compounds underwent little to no charge transfer. Commencing in 2003, the combined work of Dunbar and Omary revealed that systems combining inorganic donors with chelating, sulfur-based ligands and organic acceptors could have their spectroscopic response tuned to display low-energy charge transfer bands extending into the near-IR making them suitable candidates as photosensitizing dyes for semiconductors. In keeping with this idea, new layered charge transfer compounds combining the nitrofluorenone family of acceptors and the inorganic donor Pt(dbbpy)(tdt) (tdt = 3,4-toluenedithiolate) were prepared. The resulting complexes were characterized utilizing X-ray crystallography as well as both spectroscopic and electrochemical methods. Similar analyses were also conducted on various platinum/terpyridine salts and illustrated a level of spectroscopic tunability to that observed for the supramolcular systems composed of inorganic donors and organic acceptors.