Multi‐Mode Switching Based on Dihydroazulene/vinylheptafulvene Photochromism: Synergism of Photochromism and Redox Switching in Heteroaryl‐Functionalized Systems

Abstract

Abstract:The syntheses of the dihydroazulenes (DHAs) DHA-a-DHA-f containing covalently linked heteroaromatic subunits derived from dibenzodioxin, thianthrene, phenoxathiine, N-methylphenothiazine, N-methylphenoxazine, and N,N'-dimethylphenazine groups are described, and their spectroscopic and analytical data are reported. The dihydroazulene/vinyl heptafulvene (DHA/VHF) photochromism (photochemical forward and thermal back reaction) depends with high sensitivity on the electronic properties of the functional groups. Whereas the dimethylphenazine derivative DHAf is photochemically inactive towards rearrangement, all other DHAs (DHA-a-DHA-e) were found to isomerize to the corresponding vinylheptafulvene forms

Synthesis and anti-tubercular evaluation of some novel pyrazolo[3,4-d]pyrimidine derivatives

“…Fairly early, it was recognized that due to the low oxidation potential of this class of tricyclic nitrogen-sulfur heterocycles, their propensity to form stable radical-cations play a key role in their physiological activities (Moutet and Reverdy, 1983). More recently, owing to their reversible oxidation (Mcintyre and Gerischer, 1984), phenothiazine derivatives have become attractive supramolecular (Duesing et al, 1990;Brun et al, 1991) and material scientific motifs (Knorr and Daub, 1995;Spreitzer and Daub, 1996).…”

Synthesis and structure of new 3,7,10-substituted-phenothiazine derivatives

“…1 H and 13 C-NMR spectra were recorded at room temperature using CDCl 3 or DMSO-d 6 as solvent in 5 mm tubes on Bruker AM 300 spectrometer operating at 300 MHz for protons and 75 MHz for carbon atoms. Melting points were determined with a Kleinfeld apparatus and are uncorrected.…”

“…Many phenothiazine derivatives are fluorescent, show a low oxidation potential having the ability to form stable radical-cations, and are used as chromophores for photoinduced electron transfer experiments [2,6]. The oxidation of phenothiazine derivatives leads to the corresponding sulfoxide, which (in non-symmetrically substituted compounds) can be used to determine the chirality of the molecules [7].…”

Data storage based on photochromic and photoconvertible fluorescent proteins

“…Furthermore, for several organic compounds a multimode photochromism has been observed (Iyoda et al, 1989;Achatz et al, 1991;Spreitzer and Daub, 1996;Pina et al, 1997;Mrozek et al, 2001). However, all of these systems need combined light excitation and a second external stimulus (rise of temperature or oxidation/reduction of the system) to perform a complete change between the different states.…”