Substituent and Solvent Effects on the Excited State Deactivation Channels in Anils and Boranils

Abstract

Differently substituted anils (Schiff bases) and their boranil counterparts lacking the proton-transfer functionality have been studied using stationary and femtosecond time-resolved absorption, fluorescence, and IR techniques, combined with quantum mechanical modelling. Dual fluorescence observed in anils was attributed to excited state intramolecular proton transfer. The rate of this process varies upon changing solvent polarity. In the nitro-substituted anil, proton translocation is accompanied by intramolecular electron transfer coupled with twisting of the nitrophenyl group. The same type of structure is responsible for the emission of the corresponding boranil. A general model was proposed to explain different photophysical responses to different substitution patterns in anils and boranils. It is based on the analysis of changes in the lengths of CN and CC bonds linking the phenyl moieties. The model allows predicting the contributions of different channels that involve torsional dynamics to excited state depopulation.

Determinants of the efficiency of photon upconversion by triplet–triplet annihilation in the solid state: zinc porphyrin derivatives in PVA

“…Figure 3 shows a typical data set (16.6 mW for G1 and 2.1 mW for G2 in this case), from which it is evident that ZnTMP and ZnDBP are the best upconverters in groups G1 and G2, respectively. As is well-known from photochemical studies, [42][43][44] both the pattern of macrocycle substitution by the phenyl groups and the substitution of the phenyl moieties themselves with alkyl groups that act as impediments to free torsional motion can have substantial effects on the efficiencies of UC in these dual absorber-upconverter systems. We defer discussion of these differences until the calculations of the dimer potential surfaces have been presented.…”

Strongly Emissive and Photostable Four‐Coordinate Organoboron N,C Chelates and Their Use in Fluorescence Microscopy

“…[1][2][3][4] The structural scope includes N,O-and N,Nchelates with five-and six-membered rings as most common binding motifs [3,5] as well as bi-nuclear boron complexes. [6] Prominent examples are boron 8-hydroxyquinolinate complexes, [7,8] boron dipyrromethene (Bodipy) dyes, [9][10][11] boranils, [12,13] and boron iminocoumarins (Boricos). [14] To a lesser extent organoboron complexes with N,C-chelate systems were reported, [15][16][17][18][19] B(ppy)Mes2 compounds (ppy = 2-phenylpyridyl, Mes = mesityl) being an example.…”

Multifunctional lubricant additive based on difluoroboron derivatives of a diphenylamine antioxidant

“…Unlike the reported borate ester additives, BF 2 was selected as the B(III) fragment due to the antiwear performance of uorine containing compounds, 26,33 facile synthesis and stable structure similar to Boranil complexes. 34,35 The antioxidation and antiwear performances of the diuoroboron derivatives of SPD antioxidants as multifunctional additives were evaluated and discussed. To our delight, compared with the traditional ZDDP and the commercial antioxidant diphenylamine (DPA), the selected additive (E)-4-((3-(tert-butyl)-2-((diuoroboranyl)oxy)-5-((octylthio)methyl)benzy-lidene)amino)-N-phenylaniline (diuoroboron derivative 4a) has better wear resistance and oxidation resistance.…”