How Electronic Excitation Can be Used to Inhibit Some Mechanisms Associated to Substituent Effects

Abstract

Despite the fact that transferability and chemistry go hand in hand, transferability studies in electronically excited states (EESs) are normally omitted, although these states are becoming extremely important in modern processes and applications. In this work, it is shown that this kind of studies can be used to understand how substituent effects can be modified in EESs. Thus, for example, the analysis of the carbonyl oxygen transferability in different HCO-R molecules allowed us to find that the nO→πCO* excitation can be used to break the π conjugation associated to the resonance substituent effect. Moreover, as a direct consequence, the oxygen transferability is enhanced in the first electronically excited state.

Does the Intra‐Atomic Deformation Energy of Interacting Quantum Atoms Represent Steric Energy?

“…Topological atoms [6] are quantum atoms featuring in an increasingly popular energy decomposition scheme called Interacting Quantum Atoms (IQA). [7] IQA's growing use is demonstrated by its wide variety of applications [8][9][10][11][12][13][14][15] ranging from halogen bond formation [16] to substituent effects in electronically excited states, [17] just to name a few. The IQA partitioning scheme is an attractive candidate to serve as a bridge between chemical insight and present-day wavefunctions.…”

The ANANKE relative energy gradient (REG) method to automate IQA analysis over configurational change

“…This is a robust topological energy partitioning method that disentangles the total energy of a system into intra-and interatomic contributions of various types. IQA is inspired by earlier work [23] and has been used by several groups to study a wide variety of interactions and phenomena, including but not limited to: halogen-halogen interactions in perhalogenated ethanes [24], halogen bond formation [25], conformational analysis of diheteroaryl ketones and thioketones [26], proton transfer reactions [27], formation of an intramolecular bond path between two electronegative atoms [28], substituent effects in electronically excited states [29], cooperative and anti-cooperative effects in resonance-assisted hydrogen bonds in malondialdehyde [30], short-range electrostatics in torsional potentials [31], new insights in atomatom interactions for future drug design [32], the anomeric effect in halogenated methanols [33], hydrogen-hydrogen interaction in planar biphenyl [34], the steric repulsion in congested molecules [35], charged hydrogen-bonded complexes [36], trapping of CO 2 by adduct formation [37], and the diastereoselective allylation of aldehydes [38].…”

Where Does Electron Correlation Lie? Some Answers from a Real Space Partition

“…[12,13] Thec ombination of these methods of wavefunction analysish as been used to shed light on ab road range of problems. For example, the nature of covalent, [14,15] metallic, [16][17][18] as well as noncovalent interactions, [19][20][21][22][23][24][25][26][27][28] the origin of steric effects, [29][30][31] and the study of excited states [32][33][34] to name af ew.I QA/QTAIM provides explicit access to both one-and two-center correlation energy terms that add to the total correlatione nergy as measured with respect to deviations from the HF energy components.…”