The interplay and strength of the π⋯H F, C⋯H F, F⋯H F and F⋯H C hydrogen bonds upon the formation of multimolecular complexes based on C2H2⋯HF and C2H4⋯HF small dimers

The definitive challenge of forming uncommon pseudo‐π···H–F and C···H–F hydrogen bonds on cyclic and cubic nonpolar hydrocarbons

“…mol −1 , respectively. By the synergy and all results supplied by the NBO and QTAIM protocols, [111] an efficient relationship with a linear coefficient of 0.97 between the values of the binding energies and the intermolecular electronic density was then obtained, just like justified by Equation 12. [153] In a direct comparison (Equation 11) with the interaction energies determined at light of the supermolecule approach, the values of E 2 yield a good correlation with the variations of electronic density computed at the RCP.…”

“…In this manner, the interaction type existing in the complexes formed by cyclopropane and prismane is then recognized as being the pseudo-πÁÁÁH hydrogen bonds, such as that is known for similar systems [19,22,23,37] About the cyclobutane, its ring structure might be not sufficiently strained to provide a minimum of electron density to bind with hydrogen fluoride. Amazingly, the complexes of cyclobutane and cubane are formed by an uncommon CÁÁÁH hydrogen bond, [22,23,111] wherein independently of the four vertices or the central points on every of the six-member faces of the cubane, its proton receptor function is specifically assumed by the carbon atom. Particularly, Doedens et al [55] have explored the structure of the cubane, attributing it a bent bond exactly as is observed in the cyclopropane.…”

“…The interaction strength is successfully confirmed by the highest values of 8.19 and 7.1 KJ.mol −1 by which can be definitively established that I and III are the strongest hydrogen‐bonded complexes in comparison to II and IV , which are the weakest ones because their interaction energies are 0.42 and 0.35 kJ.mol −1 , respectively. By the synergy and all results supplied by the NBO and QTAIM protocols, [ 111 ] an efficient relationship with a linear coefficient of 0.97 between the values of the binding energies and the intermolecular electronic density was then obtained, just like justified by Equation . [ 153 ] In a direct comparison (Equation ) with the interaction energies determined at light of the supermolecule approach, the values of E 2 yield a good correlation with the variations of electronic density computed at the RCP.…”

“…In spite of the expectation of low energies for the pseudo-πÁÁÁH hydrogen bonds, the covalent character is also a target of investigation not justly due to the intermolecular strength but because the hydrocarbons may be real candidates to interact with proton donors, and therefore, the formation of hydrogen bonds should be more and better explored. [111] For our purposes, we hope to contribute for a new hydrogen bond understanding by means of a complete theoretical analysis.…”

“…In addition to the I complex, maybe III might be formed by the pseudo-πÁÁÁH hydrogen bond, and in opposition to this, in the II and IV complexes may be considered the contact of the hydrogen fluoride towards the carbon atom to form the CÁÁÁH interaction. [22,23,111] The interaction occurring in the cubane refers to the projection IV 0 , wherein the coordinate for measuring the intermolecular distance of 2.5025 Å is the central point of the four-member face. Differently of a pseudo-π bond or even if the aromaticity is taken into account, [125] but the more resembled interactions with all that has been demonstrated for the "cubane-hydrogen fluoride" complex could be those ones in T-shaped intermolecular systems formed by benzene as proton acceptor with the πÁÁÁH hydrogen bond aligned precisely in the central point of the aromatic-ring.…”