Studies Of The Photochromic Compounds As Molecular Switch Models

The dissertation is focused on the study of novel photochromic compounds based as the dithienylethens frame. The investigation and development in the area of the photochromic compounds, especially the compounds which can undergo fatigue-resistant, thermally irreversible photochromic reactions and the photoindued electron transfer (PET) in the supramolecular systems have been reviewed. In this work, we developed some new photochromic compounds and studied their photochemical properties to find the candidates for the practical utilization.The traditional photochromic compounds have the disadvantage that the recorded information is read out by light that electronically excites the photochromic compounds and the information is lost during the reading process. So the design of systems with nondestructive read-out capability is warranted. Fluorescent photoswitching molecules in which photochromic diarylethene with terpyridine units attached via a phenylene linker to the thiophene rings were synthesized. Both compounds exhibited pronounced photochromic properties. In terms of potential use for optical data storage and readout, the compounds display fluorescence discrimination between their open and closed form. This fluorescence switching could be the basis of a nondestructive read-out method. Furthermore, since the terpyridine has the ring nitrogens which can serve as multiple interaction sites to form stable coordination and hydrogen-bonded complexes with various metal ions and molecules, the compounds may act as the fluorescence detector for special metal ions, i.e., Zn²⁺.A β-cyclodextrin dimer tethered by photoswitchable dithienylethene moieties was synthesized as potentially tunable receptor. The dimer exhibits typical photochromic properties. The fluorescence titration found that the stability constant for the binding of TSPP (meso-tetrakis (4-sulfonatophenyl)porphyrin) by the closed form of the dimer is a factor 5 higher compared to that of the open form.1, 3-Dipolar cycloaddition of DTE-azomethine ylides (DTE = dithienylethene) to C₆₀ in refluxed toluene has been used to synthesize novel dumbbell-type fullerene...