Bay‐type H···H “bonding” in cis‐2‐butene and related species: QTAIM versus NBO description

Abstract

We use comparative natural bond orbital (NBO) and quantum theory of atoms in molecules (QTAIM) methods to analyze the proximal bay-type H···H interactions in cis-2-butene and related species, which lead to controversial interpretation as attractive "HH bonding" in the QTAIM framework. We address the challenging questions concerning well established structural, conformational, and vibrational properties of such species that appear to be sharply at odds with the QTAIM interpretation. In contrast to the purported "HH bonding" of QTAIM theory, NBO-based evaluation of steric (donor-donor) and hyperconjugative (donor-acceptor) interactions unambiguously portrays such H···H contacts as dominated by steric clashes that are only partially softened by weak secondary hyperconjugative interactions, contributing negligibly (bHH < 0.01) to H···H bond order. Additional details of NBO-based versus QTAIM-based description are provided by natural bond critical point analysis of topological bond critical point properties, which further emphasizes the contrast between the problematic bay-type H···H contacts and remaining noncontroversial (consensus) chemical bonds. NBO analysis is thereby shown to be fully consistent with the traditional physical organic concept of repulsive bay-type H···H contacts, including the corollary array of structural, conformational, and vibrational properties. © 2014 Wiley Periodicals, Inc.

Analysis of CF···FC Interactions on Cyclohexane and Naphthalene Frameworks

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Improved General Understanding of the Hydrogen‐Bonding Phenomena: A Reply

“…Equation (1) tautologically true, and thus unfalsifiable to its committed proponents, but raises severe questions (analogous to those for other "bookkeeping" partitionings of total energy, [14,15] ) concerning the predictive or explanatory value of the EDA dissection or its individual components. It is certainly true that the DE elstat identification [Eq.…”

Non-Covalent Interactions in Hydrogen Storage Materials LiN(CH3)2BH3 and KN(CH3)2BH3

“…Remarkably, the authors also emphasized that, apart from the mentioned non-covalent interactions, one observes untypical homopolar dihydrogen interactions of the types BH•••HB and CH•••HC which are found to determine the chain-like 1D architecture of LiN(CH3)2BH3 and 2D layers in KN(CH3)2BH3 crystal [29], Figure 1 and Figure S1. It is noteworthy that these types of connections are intuitively considered as destabilizing due to the lack of electrostatic attraction between hydrogen atoms-homopolar dihydrogen interactions (especially the intramolecular ones) are still a matter of debate in the literature [31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46]. Very recently more and more evidence has been reported in the literature that highlight the stabilizing nature of homopolar dihydrogen interactions [17,21,29,[36][37][38][39][40][41][42][43][44][45][46].…”