Many qualitative structure-property correlations between diradical character and emerging molecular properties are known. For example, the increase of diradical character further decreases the singlet-triplet energy gap. Here we show that inclusion of thiophenes within a quinoidal polycyclic hydrocarbon imparts appreciable diradical character yet retains the large singlet-triplet energy gap, a phenomenon that has no precedent in the literature. The low aromatic character of thiophene and its electron-rich nature are the key properties leading to these unique findings. A new indenoindenodibenzothiophene scaffold has been prepared and fully characterized by several spectroscopies, magnetic measurements, solid-state X-ray and state-of-the-art quantum chemical calculations, all corroborating this unique dichotomy between the diradical input and the emerging magnetic properties. New structure-property relationships such as these are not only extremely important in the field of diradical chemistry and organic electronics, but also provide new insights into the versatility of π-electron chemical bonding.

A spiropyran derivative containing an acridinium and a phenoxide moieties was found to exhibit both halochromism and electrochromism in response to acid stimulation and oxidative stimulation, respectively. Variable scan-rate voltammetric studies revealed that the acridine spiropyran undergoes a reversible conversion between a closed-ring and an open-ring form during the redox cycle. The presence of a ring-opened radical cation species was demonstrated by simultaneous electrochemical ESR measurements.

A 1,4-dihydropyridine derivative, lacking carbonyl groups and containing bulky aryl substituents, was synthesized and found to have a high hydride donating ability, acid resistance and reusability. Thermodynamic parameters for electron...

All the proton magnetic resonance signals of citral a (I) and b (11) have been assigned by use of the spin-decoupling method and by application of nuclear Overhauser effects. s-trans Conformations of the aldehyde groups have been confirmed by use of the solvent effect of benzene. The conclusions are consistent with those of earlier workers.THE structures of citral a and b were established1 by groups were shown4 to be s-trans by measurements of chemical methods, their proton magnetic resonance molecular polarisability. This Paper reports confirm-(p.m.r.) spectra were examined 293 in connection with their ation of the configurations and conformations by a new configurations, and the conformations of the aldehyde approach, which involves spin-decoupling experiments,

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