Journal of Molecular Graphics and Modelling 48 (2014) 1–8 Contents lists available at ScienceDirect Journal of Molecular Graphics and Modelling journa l h om epage: www.elsevier.com/locate/JMGM Modeling the intermolecular interactions: Molecular structure of N-3-hydroxyphenyl-4-methoxybenzamide Sedat Karabulut a,∗ , Hilmi Namli a , Raif Kurtaran b , Leyla Tatar Yildirim c , Jerzy Leszczynski d a Balıkesir University, Faculty of Science and Literature, Department of Chemistry, 10145 Cagis, Balikesir, Turkey b Akdeniz University, Alanya Faculty of Engineering, Materials Science and Engineering, Antalya, Turkey c Hacettepe University, Department of Engineering Physics, Beytepe, 06800 Ankara, Turkey d Jackson State University, Interdisciplinary Nanotoxicology Center, Jackson, MS, USA a r t i c l e i n f o Article history: Accepted 16 November 2013 Available online 28 November 2013 Keywords: Molecular structure Dimer Amide X-ray DFT a b s t r a c t The title compound, N-3-hydroxyphenyl-4-methoxybenzamide (3) was prepared by the acylation reac- tion of 3-aminophenol (1) and 4-metoxybenzoylchloride (2) in THF and characterized by 1 H NMR, 13 C NMR and elemental analysis. Molecular structure of the crystal was determined by single crystal X-ray diffraction and DFT calculations. 3 crystallizes in monoclinic P2 1 /c space group. The influence of inter- molecular interactions (dimerization and crystal packing) on molecular geometry has been evaluated by calculations performed for three different models; monomer (3), dimer (4) and dimer with added unit cell contacts (5). Molecular structure of 3, 4 and 5 was optimized by applying B3LYP method with 6- 31G+(d,p) basis set in gas phase and compared with X-ray crystallographic data including bond lengths, bond angles and selected dihedral angles. It has been concluded that although the crystal packing and dimerization have a minor effect on bond lengths and angles, however, these interactions are important for the dihedral angles and the rotational conformation of aromatic rings. © 2013 Elsevier Inc. All rights reserved. 1. Introduction The amide group always remains in the center of interest to scientists because of large variety of applications associated with compounds with such functional groups. Its presence in molecules may render them the property of efficient complexing agents, effec- tive herbicides, in addition to importance of the amide fragment as the vital part of biomolecules [1]. The physical properties of NH CO functional group have attracted attention of many experimental and theoretical scien- tists [2]. In addition to physical properties, also conformational properties of NH CO group have been studied extensively. For example, formamide and substituted amides have been detected as planar species in both gas phase and solid state [3–9]. How- ever, there are also some experimental results that report small deviations from planarity of amide functional group [6]. There are several applications of aromatic amide derivatives in crystal engineering [10] because of the very active partic- ipating properties (electron charge distribution, non-vanishing electrostatic multipole moment, magnetic ring current) of aromatic compounds in numerous interactions [11]. Nature of substituent ∗ Corresponding author. Tel.: +90 2666121000x1116; fax: +90 2666121215. E-mail addresses: sedatk@balikesir.edu.tr, sedat@icnanotox.org (S. Karabulut). generally affects the molecular geometry, reactivity, physicochemi- cal and biological properties of aromatic compounds [12–14]. Based on the resonance or inductive effects of substituents they can be either classified as electron-donor or acceptor. It is well known that hydrogen bonds are among interactions which are mostly responsible for arrangement of molecules in crystal structure [15]. Thus the molecular structures of aromatic amides should be well analyzed because of their diversity caused by hydrogen bonding capacity. Hydrogen bonding is one of the most important non-covalent interactions in the nature. The most famous examples of effects of hydrogen bonding on various species include property of water in different phases, structures and char- acteristics of proteins and nucleic acids [16]. The molecular geometry of a dimeric amide structure basically depends on three main factors; (i) the molecular properties of the molecule itself (stereochemical and stereoelectronic effects), (ii) effect of dimerization, (iii) crystal packing effects [17,18]. The title compound (Fig. 1) is an example of hydrogen bonded dimeric amide. As the result of a crystallization process millions of molecules are gather together into unique ordered arrangement. This arrangement is repeatable, under the same crystallization con- ditions [19]. In the present work experimental study has been comple- mented by computational approach. The geometric parameters of the title compound were calculated using following input 1093-3263/$ – see front matter © 2013 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.jmgm.2013.11.001