Switching between mono- and doubly-reduced odd alternant hydrocarbon: Designing redox catalyst

Since the early Hückel molecular orbital (HMO) calculations in 1950, it is well known that the odd alternant hydrocarbon (OAH), phenalenyl (PLY) system can exist in three redox states: closed...

A new cross-conjugated mesomeric betaine

Cross-conjugated mesomeric betaine (CCMB) has been defined as the dipolar species in which positive and negative charges are exclusively restricted to different parts of the molecule. A new CCMB isoconjugate with odd non-alternant hydrocarbon anion is reported.

Diboron- and Diaza-Doped Anthracenes and Phenanthrenes: Their Electronic Structures for Being Singlet Fission Chromophores

<p>We used quantum chemistry methods at the levels of mixed-reference spin-flipping time-dependent density functional theory and multireference perturbation theory to study diboron- and diaza-doped anthracenes and phenanthrenes. This class of structures recently surged as potential singlet fission chromophores. We studied electronic structures of their excited states and clarify the reasons why they satisfy or fail to satisfy the energy criteria for singlet fission chromophores. Many studied structures have their S₁ states not dominated by HOMO->LUMO excitation, so that they cannot be described using the conventional two sites model. This is attributed to frontier orbital energy shifts induced by the doping and different charge transfer energies in different one-electron singlet excitations, or in other words different polarizations of hole and/or particle orbitals in their S₁ and T₁ states. There is a mirror relation between the orbital energy shifts induced by diboron- and diaza-dopings, which, together with alternant hydrocarbon pairings of occupied and unoccupied orbitals, leads to more mirror relations between the excited states' electronic structures of the two types of doped structures. </p>

Diboron- and Diaza-Doped Anthracenes and Phenanthrenes: Their Electronic Structures for Being Singlet Fission Chromophores

<p>We used quantum chemistry methods at the levels of mixed-reference spin-flipping time-dependent density functional theory and multireference perturbation theory to study diboron- and diaza-doped anthracenes and phenanthrenes. This class of structures recently surged as potential singlet fission chromophores. We studied electronic structures of their excited states and clarify the reasons why they satisfy or fail to satisfy the energy criteria for singlet fission chromophores. Many studied structures have their S₁ states not dominated by HOMO->LUMO excitation, so that they cannot be described using the conventional two sites model. This is attributed to frontier orbital energy shifts induced by the doping and different charge transfer energies in different one-electron singlet excitations, or in other words different polarizations of hole and/or particle orbitals in their S₁ and T₁ states. There is a mirror relation between the orbital energy shifts induced by diboron- and diaza-dopings, which, together with alternant hydrocarbon pairings of occupied and unoccupied orbitals, leads to more mirror relations between the excited states' electronic structures of the two types of doped structures. </p>