Cooperative and anticooperative effects in resonance assisted hydrogen bonds in merged structures of malondialdehyde

Abstract

We analyzed non-additive effects in resonance assisted hydrogen bonds (RAHB) in different β-enolones, which are archetypal compounds of this type of interactions. For this purpose, we used (i ) potential energy curves to compute the formation energy, ∆E

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].…”

The effects of higher orders of perturbation theory on the correlation energy of atoms and bonds in molecules

“…When it comes to the total self-correlation energies the difference in going from MP3 to MP4 (-49.0 kJ mol 21 ) has about the same magnitude as that going from MP2 to MP3 (68.3 kJ mol 21 ). However, the total bond correlation energies display a much more polarized behavior because the change from MP2 to MP3 is very large (-100.6 kJ mol 21 ) but the change from MP3 to MP4 is almost negligible in comparison, at 4.8 kJ mol 21 . The changes in the total through-space (interatomic) correlation energies are all smaller than 10 kJ mol 21 .…”

“…The effects of dimerization can be split into two parts: (i) the change within each individual HF molecule on FIG URE 1 The geometry of the dimers and trimer with bond lengths (Å) and angles (degrees) The atomic labels are given in Figure 1 and the energies are in kJ mol 21 . a The values given are for the MP2, MP3, and MP4SDQ energies, respectively.…”

“…The atom labels are given in Figure 1 and the energies are in kJ mol 21 . in error by about 23.0 kJ mol 21 (i.e., 24.5 kJ mol 21 ).…”

“…However, when correlation energy is combined with exchange energy, as was recently made possible [17] in DFT, then it is calculated in a growing number of studies, due to DFT's reduced computational cost. In the last few years a surge of papers appeared using IQA and offering chemical insight into a wide variety of phenomena, such as halogen-halogen interactions in perhalogenated ethanes, [18] conformations in diheteroaryl ketones and thioketones, [19] substituent effects in electronically excited states, [20] cooperative and anti-cooperative effects in resonance-assisted hydrogen bonds in malondialdehyde, [21] the hydrogen-hydrogen interaction in planar biphenyl, [22] steric repulsion in congested molecules, [23] and the diastereoselective allylation of aldehydes. [24] None of the aforementioned work reports atomically partitioned correlation energy by itself (i.e., isolated from exchange) but the current article does, and obtains it from MP2, MP3, and MP4SDQ wave functions.…”