Photochemistry of 1‐ and 2‐Naphthols and Their Water Clusters: The Role of ¹ππ*(L_a) Mediated Hydrogen Transfer to Carbon Atoms

Abstract

The computational analysis of the isomer- and conformer-dependent photochemistry of 1- and 2-naphthols and their microsolvated water clusters is motivated by their very different excited state reactivities. We present evidence that 1- and 2-naphthol follow distinct excited state deactivation pathways. The deactivation of 2-naphthols, 2-naphthol water clusters, as well as of the anti conformer of 1-naphthol is mediated by the optically dark πσ* state. The dynamics of the πσ* surface leads to the homolytic cleavage of the OH bond. On the contrary, the excited state deactivation of syn 1-naphthol and 1-naphthol water clusters follows an uncommon reaction pathway. Upon excitation to the bright ππ*(L ) state, a highly specific excited state hydrogen transfer (ESHT) to carbon atoms C8 and C5 takes place, yielding 1,8- and 1,5-naphthoquinone methides. The ESHT pathway arises from the intrinsic electronic properties of the ππ*(L ) state of 1-naphthols.

Fluorescence Quenching in BODIPY Dyes: The Role of Intramolecular Interactions and Charge Transfer

“…ADC(2) was recently applied to various organic molecules, typically providing the results consistent with experiments. The method can also be used for optimizing conical intersections, although it does not provide a correct dimensionality of the crossing seam (for S 1 /S 0 crossing) . The computations were performed with Turbomole 7.0.2 package and the strict ADC(2) method implemented therein.…”

Caveat when using ADC(2) for studying the photochemistry of carbonyl-containing molecules

“…Plasser et al 18 investigated the application of different single-reference methods in excited-state molecular dynamics of adenine, placing ADC(2) as a serious competitor to the commonly-accepted TDDFT for nonadiabatic dynamics. Following these reports, an explosion of studies employing ADC(2) in excited-state dynamics appeared in the literature, [19][20][21][22][23][24][25][26][27][28][29][30][31][32][33] also mapping the reaction paths between the Franck-Condon (FC) geometry and the electronic states crossings, [28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45] and calculating absorption properties of functional molecules. 46,47 The community has gained a large confidence with ADC(2), to the point where many studies employing it do not contain systematic comparisons with high-level multireference methods.…”

“…46,47 The community has gained a large confidence with ADC(2), to the point where many studies employing it do not contain systematic comparisons with high-level multireference methods. 19,24,[26][27][28][29][38][39][40][41][42] This is understandable though considering that the latter studies involve middle-sized or bigger molecular systems. For these systems ADC(2) is an ace in the hole, appearing as an ideal compromise between accuracy and computational efficiency.…”

Substitution pattern on anthrol carbaldehydes: excited state intramolecular proton transfer (ESIPT) with a lack of phototautomer fluorescence

“…59,60 The method is suitable for investigating low lying ππ* states in fused aromatic ring systems as the ordering of the La(ππ*) or Lb(ππ*) states and the interstate gap are typically well described with ADC(2). 61,62 Adiabatic excitation energies were computed by optimizing both ground and excited state structures.…”