Overlap properties of chemical bonds in generic systems including unusual bonding situations

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ORIGINAL PAPER

Overlap properties of chemical bonds in generic systems including unusual bonding situations Renaldo T. Moura Jr 1

&

Albano N. Carneiro Neto 2

&

Oscar L. Malta 3

&

Ricardo L. Longo 3

Received: 29 March 2020 / Accepted: 7 September 2020 # Springer-Verlag GmbH Germany, part of Springer Nature 2020

Abstract Chemical bond is a ubiquitous and fundamental concept in chemistry, in which the overlap plays a defining role. By using a new approach based on localized molecular orbitals, the overlap properties, e.g., polarizability αOP , population pOP, intra Jintra OP , and inter inter JOP repulsions, and density ρOP, of polyatomic systems were calculated, analyzed, and correlated. Several trends are shown for these properties, which are rationalized by the balance of some well-known effects, such as, electron donor/withdrawing character and electronegativity. The overlap properties of unusual bonds are also analyzed, revealing an OZn4(OOCH)6 structure with four equivalent Zn–O chemical bonds with overlap properties like the O–O bond in H2O2, while in protonated methane þ þ CHþ 5 , it is observed that a CH3⋯H2 bond pattern at the equilibrium structure changes to a CH3 ⋯H2 pattern upon dissociation. Charge-shift resonance energies, atom-in-molecule properties, and the lone-pair-bond-weakening effects are related to the overlap properties, which can provide alternative views and insights into chemical bonds. Keywords Chemical bonds . Overlap properties . Localized molecular orbitals . Polarizability

Introduction At the dawn of the twentieth century, Lewis introduced the concept of a covalent chemical bond as a pair of electrons being shared by two atoms [1]. This concept was popularized by Langmuir that introduced the term covalency to distinguish it from the concept of valence used at that time in describing

This paper belongs to Topical Collection XX - Brazilian Symposium of Theoretical Chemistry (SBQT2019) Electronic supplementary material The online version of this article (https://doi.org/10.1007/s00894-020-04535-w) contains supplementary material, which is available to authorized users. * Renaldo T. Moura, Jr [email protected] * Ricardo L. Longo [email protected] 1

Department of Chemistry and Physics, Federal University of Paraíba, Areia 58397-000, Brazil

2

Physics Department and CICECO – Aveiro Institute of Materials, University of Aveiro, 3810-193 Aveiro, Portugal

3

Departamento de Química Fundamental, Universidade Federal de Pernambuco, Recife 50740-560, Brazil

chemical reactivity and affinity [2]. Covalency was then defined as the number of pairs of electrons that a given atom shares with its neighbors. The first treatment of the covalent chemical bond in the H2 molecule using quantum mechanics was performed by Heitler and London in 1927 [3, 4]. Soon after, Pauling proposed a quantitative measurement of the covalency and ionicity concepts based on the electronegativity differences of the atoms involved in the bond [5, 6]. Chemical bond has then become one of the most impor