Surface Hopping Dynamics with the Frenkel Exciton Model in a Semiempirical Framework.

We present an implementation of the Frenkel exciton model in the framework of the semiempirical floating occupation molecular orbitals-configuration interaction (FOMO-CI) electronic structure method, aimed at simulating the dynamics of multichromophoric systems, in which excitation energy transfer can occur, by a very efficient approach. The nonadiabatic molecular dynamics is here dealt with by the surface hopping method, but the implementation we proposed is compatible with other dynamical approaches. The exciton coupling is computed either exactly, within the semiempirical approximation considered, or by resorting to transition atomic charges.

CASPT2, CASSCF and non-adiabatic molecular dynamics (NAMD) studies on the low-lying electronic states of 1H-1,2,3-triazole photolysis.

The photolysis mechanisms of 1H-1,2,3-triazole and 1H-1,2,3-benzotriazole were elucidated by employing multiconfigurational methods (CASSCF and CASPT2). The potential energy curves and crossing points for the low-lying excited states were analyzed. In addition to the static electronic structure calculations, non-adiabatic molecular dynamics (NAMD) was propagated at the CASSCF level using SHARC (Surface Hopping including ARbitrary Couplings) dynamics in order to verify the proposed static picture, thereby understanding the possible reaction paths and the time scale of the photo-induced events.

Intramolecular Hydroamination of Selenoalkynes to 2-Selenylindoles in the Absence of Catalyst.

In this work, a series of 2-chalcogenylindoles was synthesized by an efficient methodology, starting from chalcogenoalkynes, including a previously unreported tellurium indole derivative. For the first time, these 2-substituted chalcogenylindoles were obtained in the absence of metal catalyst or base, under thermal conditions only. In addition, the results described herein represent a methodology with inverse regioselectivity for the chalcogen functionalization of indoles.

Photocatalytic Reverse Semi-Combustion Driven by Ionic Liquids.

The simple photolysis of CO in aqueous solutions to generate CO and/or hydrocarbons and derivatives in the presence of a catalyst is considered to be a clean and efficient approach for utilizing CO as a C1 building block. Despite the huge efforts dedicated to this transformation using either semiconductors or homogeneous catalysts, only small improvements of the catalytic activity have been achieved so far. This article reports that simple aqueous solutions of organic salts-denominated as ionic liquids-can efficiently photo-reduce CO to CO without using photosensitizers or sacrificial agents.

Proton-Transfer-Based Azides with Fluorescence Off-On Response for Detection of Hydrogen Sulfide: An Experimental, Theoretical, and Bioimaging Study.

This work describes the synthesis of photoactive proton transfer compounds based on the benzazolic core containing the azide group. The compounds present absorption in the UV region and fluorescence emission in the visible region of the spectra with large Stokes shift due to a phototautomerism in the excited state (ESIPT). The azide location on the benzazolic structure presented a noteworthy role on their photophysics, leading to fluorescence quenching.