The role of π-π stacking and hydrogen-bonding interactions in the assembly of a series of isostructural group IIB coordination compounds.

Taraneh Hajiashrafi,Antonio Frontera,Farnoush Kia,Keith J Flanagan,Roghayeh Zekriazadeh,Antonio Bauzá,Mathias O Senge

doi:10.1107/s2053229618018314

Abstract

The supramolecular chemistry of coordination compounds has become an important research domain of modern inorganic chemistry. Herein, six isostructural group IIB coordination compounds containing a 2-{[(2-methoxyphenyl)imino]methyl}phenol ligand, namely dichloridobis(2-{(E)-[(2-methoxyphenyl)azaniumylidene]methyl}phenolato-κO)zinc(II), [ZnCl2(C28H26N2O4)], 1, diiodidobis(2-{(E)-[(2-methoxyphenyl)azaniumylidene]methyl}phenolato-κO)zinc(II), [ZnI2(C28H26N2O4)], 2, dibromidobis(2-{(E)-[(2-methoxyphenyl)azaniumylidene]methyl}phenolato-κO)cadmium(II), [CdBr2(C28H26N2O4)], 3, diiodidobis(2-{(E)-[(2-methoxyphenyl)azaniumylidene]methyl}phenolato-κO)cadmium(II), [CdI2(C28H26N2O4)], 4, dichloridobis(2-{(E)-[(2-methoxyphenyl)azaniumylidene]methyl}phenolato-κO)mercury(II), [HgCl2(C28H26N2O4)], 5, and diiodidobis(2-{(E)-[(2-methoxyphenyl)azaniumylidene]methyl}phenolato-κO)mercury(II), [HgI2(C28H26N2O4)], 6, were synthesized and characterized by X-ray crystallography and spectroscopic techniques. All six compounds exhibit an infinite one-dimensional ladder in the solid state governed by the formation of hydrogen-bonding and π-π stacking interactions. The crystal structures of these compounds were studied using geometrical and Hirshfeld surface analyses. They have also been studied using M06-2X/def2-TZVP calculations and Bader's theory of `atoms in molecules'. The energies associated with the interactions, including the contribution of the different forces, have been evaluated. In general, the π-π stacking interactions are stronger than those reported for conventional π-π complexes, which is attributed to the influence of the metal coordination, which is stronger for Zn than either Cd or Hg. The results reported herein might be useful for understanding the solid-state architecture of metal-containing materials that contain MIIX2 subunits and aromatic organic ligands.

Highlights

IntroductionThere are some reports that provide evidence suggesting the crucial role of nondirectional intermolecular interactions, such as – stacking (Khavasi & Azizpoor Fard, 2010; Janiak, 2000; Khavasi & Sadegh, 2014; Semeniuc et al, 2010), for designing the supramolecular architecture of metal-containing species in the solid state
The energies associated with the interactions, including the contribution of the different forces, have been evaluated
The – stacking interactions are stronger than those reported for conventional – complexes, which is attributed to the influence of the metal coordination, which is stronger for Zn than either Cd or Hg

Summary

Introduction

There are some reports that provide evidence suggesting the crucial role of nondirectional intermolecular interactions, such as – stacking (Khavasi & Azizpoor Fard, 2010; Janiak, 2000; Khavasi & Sadegh, 2014; Semeniuc et al, 2010), for designing the supramolecular architecture of metal-containing species in the solid state In this regard, supramolecular chemists and crystal engineers have explored and studied the use of noncovalent interactions as a key tool for constructing supramolecular architectures of metal-containing building units in the solid state in which X-ray crystallography could provide a detailed picture of the supramolecular structure (Desiraju, 2014; Blake et al, 1999; Ðakovicet al., 2018). These studies revealed that the ultimate supramolecular architecture of self-assembled metal-containing compounds could be affected by various factors, such as ligand and metal geometries (Khavasi et al, 2012; Hajiashrafi et al, 2013), counter-ions (Schottel et al, 2006; Zeng et al, 2010) and reaction conditions (Khavasi & Mohammad Sadegh, 2010; Mahata et al, 2009)

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Results

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