Advances in computational photochemistry and chemiluminescence of biological and nanotechnological molecules

Abstract

Recent advances (2014-2015) in computational photochemistry and chemiluminescence derive from the development of theory and from the application of state-of-the-art and new methodology to challenging electronic-structure problems. Method developments have mainly focused, first, on the improvement of approximate and cheap methods to provide a better description of non-adiabatic processes, second, on the modification of accurate methods in order to decrease the computation time and, finally, on dynamics approaches able to provide information that can be directly compared with experimental data, such as yields and lifetimes. Applications of the ab initio quantum-chemistry methods have given rise to relevant findings in distinct fields of the excited-state chemistry. We briefly summarise, in this chapter, the achievements on photochemical mechanisms and chemically-induced excited-state phenomena of interest in biology and nanotechnology.

Unimolecular Decomposition Mechanism of 1,2-Dioxetanedione: Concerted or Biradical? That is the Question!

“…The state-of-the-art ab initio findings, on the other hand, confirm a stepwise biradical mechanism for unimolecular decomposition of 1,2-dioxetane and 1,2-dioxetanone. , Recently, da Silva et al performed theoretical studies employing density functional theory (DFT) methods to explore the unimolecular decomposition PESs of the ground and lowest-lying excited states of 1,2-dioxetanedione . However, methods of higher accuracy are indispensable for understanding the state crossings in detail . It should be mentioned that for four-membered ring peroxide decompositions, like 1,2-dioxetanes and similar derivatives, the pathway always involves O–O and C–C bond cleavages, leading to the formation of two extremely stable carbonyl fragments .…”

“…14 methods of higher accuracy are indispensable for understanding the state crossings in detail. 15 It should be mentioned that for four-membered ring peroxide decompositions, like 1,2dioxetanes and similar derivatives, the pathway always involves O−O and C−C bond cleavages, leading to the formation of two extremely stable carbonyl fragments. 16 This behavior is different from that of endoperoxides; cyclic peroxides consisted of at least five-membered rings, which are known to decompose predominantly by a pathway that involves C−O bond breakage, and the formation of singlet oxygen, as also indicated by recent theoretical calculations.…”

Photoluminescence mechanisms of BF2-formazanate dye sensitizers: a theoretical study

“…Theoretical studies have shown that ISC in aromatic organic compounds can be mediated by intramolecular motions 35 such as molecular rotation or twist; 36 thus, reaction pathway optimization began with the S 0 → S 1 vertically excited precursor (I)*, from which the PESs for the rotations of the torsional angles ω 1 and ω 2 ( Fig. 2 ) were constructed.…”

Computational Bioluminescence

“…The combined QM and molecular mechanics (MM) scheme is used to calculate the real system and consider all kinds of effects. In the past 14 years, we have investigated the mechanism or chemistry of BL of firefly, [ 24‐37 ] Cypridina , [ 38‐40 ] Aequorin, [ 41‐42 ] Obelia, [ 43‐44 ] bacteria, [ 45‐47 ] firefly squid, [ 48 ] dinoflagellate, [ 49‐50 ] Latia, [ 51 ] and earthworm. [ 52 ] Some of our theoretical studies were involved in the latest book “ Bioluminescence, the nature of light ” [ 53 ] written by John Lee, one of the pioneers in BL field.…”