Experimental and computational electrochemistry of quinazolinespirohexadienone molecular switches - differential electrochromic vs photochromic behavior.

Our undergraduate research group has long focused on the preparation and investigation of electron-deficient analogs of the perimidinespirohexadienone (PSHD) family of photochromic molecular switches for potential application as "photochromic photooxidants" for gating sensitivity to photoinduced charge transfer. We previously reported the photochemistry of two closely related and more reducible quinazolinespirohexadienones (QSHDs), wherein the naphthalene of the PSHD is replaced with a quinoline. In the present work, we report our investigation of the electrochemistry of these asymmetric QSHDs.

Synthesis and structural investigation of an "oxazinoquinolinespirohexadienone" that only exists as its long-wavelength ring-opened quinonimine isomer.

The spirocyclic oxazinoquinolinespirohexadienone (OSHD) "photochromes" are computationally predicted to be an attractive target as electron deficient analogues of the perimidinespirohexadienone (PSHD) photochromes, for eventual application as photochromic photooxidants. We have found the literature method for their preparation unsuitable and present an alternative synthesis. Unfortunately the product of this synthesis is the long wavelength (LW) ring-opened quinonimine isomer of the OSHD.

Expanding and testing a computational method for predicting the ground state reduction potentials of organic molecules on the basis of empirical correlation to experiment.

A method for predicting the ground state reduction potentials of organic molecules on the basis of the correlation of computed energy differences between the starting S(0) and one-electron-reduced D(0) species with experimental reduction potentials in acetonitrile has been expanded to cover 3.5 V of potential range and 74 compounds across 6 broad families of molecules. Utilizing the conductor-like polarizable continuum model of implicit solvent allows a global correlation that is computationally efficient and has improved accuracy, with r(2) > 0.