The performances, in the description of excited state potential energy surfaces, of several density functional approximations representative of the currently most applied exchange correlation functionals’ families have been tested with respect to post Hartree-Fock references (here Symmetry Adapted Cluster-Configuration Interaction results). An experimentally well-characterized intermolecular proton transfer reaction has been considered as test case. The computed potential energy profiles were analyzed both in the gas phase and in toluene solution, here represented as a polarizable continuum model. The presence of intermolecular (dark) and intramolecular (bright) charge transfer excited states, whose polarity strongly differs along the reaction pathway, makes clear that only subtle compensation between spurious electronic effects—related to the incorrect asymptotic behavior of the functional—and solvent sta...
We report the first copper-catalyzed olefinic ethoxy carbonyl difluoromethylation of alkenyl thioethers via direct C–H bond functionalization using BrCF2COOEt. The developed methodology allows the preparation of trisubstituted olefins with a controlled stereochemistry. A mechanistic study is reported and a radical mechanism is revealed.
Aiming at developing an affordable and easily implementable computational protocol for routine prediction of spectral properties of rigid molecular dyes, density functional theory, and time-dependent density functional theory were used in conjunction with a vibronic coupling scheme for band shape estimate. To predict the perceived color of molecules in solution, a model has been setup linking the UV-vis spectra predicted at ab initio level to the L*a*b* colorimetric parameters. The results show that a mixed protocol, implying the use of a global hybrid functional for the prediction of adiabatic energy differences and a range separated hybrid for the prediction of potential energy curvature, allows perceived colors to be quantitatively predicted, as demonstrated by the comparison of L*a*b* colorimetric parameters obtained from computed and experimental spectra.
Aggregation-induced emission can often be explained via the restriction of intramolecular rotation paradigm and/or excimer formation. The enhanced luminescence recently observed for aggregates of Fluorenone derivatives are no exception. In this work, however, we use a recently developed excited state electrostatic embedding technique to demonstrate that enhanced emission in diphenylfluorenone can be rationalized by considering a single-molecule process, in which the field induced by the crystalline environment at the excited state enhances the relative brightness of otherwise poorly emissive states, resulting in both enhanced fluorescence and a substantial bathochromic shift when compared with emission in dilute solution.