Study of chemical bonding in the interhalogen complexes based on density functional theory
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Study of chemical bonding in the interhalogen complexes based on density functional theory O. Kh. Poleshchuk1 · A. V. Fateev2 · A. G. Yarkova2 · M. N. Ermakhanov3 · P. A. Saidakhmetov3
© Springer International Publishing Switzerland 2016
Abstract The density functional theory analysis was used for a number XYL complexes (XY is a dihalogen molecule and L is a Lewis base), formed between molecules I2 , ICl, IBr and pyridine. The calculated geometrical parameters, IR spectra and nuclear quadrupole interaction constants of iodine are consistent with the data of microwave spectroscopy and nuclear quadrupole resonance. The good correlation between the experimental and calculated binding energies of the inner electrons of iodine, chlorine and nitrogen atoms were found with the calculation using both Gaussian and Slater functions. The comparison of experimental and calculated changes in the electron density on the atoms upon complex formation suggested the choice of scheme for calculating the effective charge on the atoms, which allow us to interpret the experimental spectra. It is shown that the use of both calculated schemes allows us to predict the enthalpy of complex formation in close agreement with the experimental values. The energy analysis shows that in the complexes the electrostatic binding energy dominates that of covalent binding. Keywords Density functional theory · Quadrupole coupling constant · Photoelectron spectroscopy · Effective atomic charge
This article is part of the Topical Collection on Proceedings of the International Conference on Hyperfine Interactions and their Applications (HYPERFINE 2016), Leuven, Belgium, 3–8 July 2016 O. Kh. Poleshchuk
[email protected] 1
National Research Tomsk Polytechnic University, Tomsk, Russia
2
Tomsk State Pedagogical University, Tomsk, Russia
3
M. Auezov South Kazakhstan State University, Shymkent, Republic of Kazakhstan
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Hyperfine Interact (2016) 237:144
1 Introduction Structure and bonding in Lewis acid-base complexes is the subject of the chemical of interest [1]. Most of the complexes of halogens and interhalogens have dative chemical bonds that are intermediate between van der Waals interaction and fully formed chemical bonds [2]. On the one hand these complexes have an interesting structure, on the other -they provide an interesting perspective in understanding the nature of the donor-acceptor chemical bond. The advantage of the study LXY complexes, where L is a Lewis base and X and Y = F, Cl, Br, or I consists in the fact that N, Cl, Br and I are quadrupole nuclei, and therefore rotational spectra of these complexes reveal nuclear quadrupole hyperfine structure. Experimentally obtained spectroscopic properties relate to the isolated molecule and are therefore most relevant for comparison with the results of ab initio calculations at a high level of theory. Changes of nuclear quadrupole coupling constants (NQCC) of halogens observed when an organic ligand L is brought to its equilibrium position in LXY are of specific interes
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