Evaluation of N—H...S and N—H...π interactions inO,O′-diethylN-(2,4,6-trimethylphenyl)thiophosphate: a combination of X-ray crystallographic and theoretical studies

Abstract

In the crystal structure of O,O'-diethyl N-(2,4,6-trimethylphenyl)thiophosphate, CHNOPS, two symmetrically independent thiophosphoramide molecules are linked through N-H...S and N-H...π hydrogen bonds to form a noncentrosymmetric dimer, with Z' = 2. The strengths of the hydrogen bonds were evaluated using density functional theory (DFT) at the M06-2X level within the 6-311++G(d,p) basis set, and by considering the quantum theory of atoms in molecules (QTAIM). It was found that the N-H...S hydrogen bond is slightly stronger than the N-H...π hydrogen bond. This is reflected in differences between the calculated N-H stretching frequencies of the isolated molecules and the frequencies of the same N-H units involved in the different hydrogen bonds of the hydrogen-bonded dimer. For these hydrogen bonds, the corresponding charge transfers, i.e. lp (or π)→σ*, were studied, according to the second-order perturbation theory in natural bond orbital (NBO) methodology. Hirshfeld surface analysis was applied for a detailed investigation of all the contacts participating in the crystal packing.

Exploring concomitant/conformational dimorphism in a difluoro-substituted phosphoramidate derivative

“…Approximately 91 hits have been reported in the Cambridge Structural Database (CSD, Version 5.39, November 2017 + 4 updates; Groom et al, 2016) (the restrictions being nondisordered, no-error, nonpolymeric systems) for the The concomitant occurrence of crystals of Forms I and II phosphoramidate skeleton and this shows that this class of compound has merely been explored in terms of crystal structure and polymorphism (Torabi Farkhani et al, 2018;Tarahhomi et al, 2013). With almost one million entries in the CSD, it provides a vast database to determine statistical trends in this class of solids.…”

A combined X-ray crystallography and theoretical study of N—H...OX (X is =P and —C) hydrogen bonds in two new structures with a (C—O)2(N)P(=Y) (Y is O and S) skeleton

“…Quantum chemical calculations were also applied to an evaluation of N-HÁ Á ÁY P (Y = O and S) hydrogen-bond strengths, which in a typical N-HÁ Á ÁS P hydrogen bond examined is about one-half with respect to N-HÁ Á ÁO P, e.g. 4.00 kcal mol À1 (1 kcal mol À1 = 4.184 kJ mol À1 ) in [2,4,6-(CH 3 ) 3 C 6 H 2 NH]P(S)[OCH 2 CH 3 ] 2 (Torabi Farkhani et al, 2018) and 6.99 kcal mol À1 in [(4-CH 3 O)C 6 H 4 C(O)NH]-P(O)[NHCH 2 C 6 H 4 (4-CH 3 )] 2 (Taherzadeh et al, 2017). Furthermore, Shainyan et al (2010) reported the calculated hydrogen-bond energies for N-HÁ Á ÁS and N-HÁ Á ÁO within the ranges 3.8-6.0 and 4.8-8.6 kcal mol À1 , respectively, for some sulfonamide derivatives.…”

Investigation of crystal structures, energetics and isostructurality in halogen-substituted phosphoramidates

“…[CSD refcodes LEQRIK/LEQRIK01 (Gholivand et al, 2013) and HOBSID/HOBSID01 (Hasija & Chopra, 2019)]. On exploring more, derivatives of phosphoric acid have been unraveled, where the study encompasses the detailed investigation of the crystalline arrangement via the presence of different intermolecular interactions (DuPlessis et al, 1982;Tarahhomi et al, 2012Tarahhomi et al, , 2013Hamzehee et al, 2016;Farkhani et al, 2018;Taherzadeh et al, 2021).…”