Halogen Bonding in New Dichloride-Cobalt(II) Complex with Iodo Substituted Chalcone Ligands

Lukáš Masaryk,Ján Moncol,Ivan Nemec,Radovan Herchel

doi:10.3390/cryst10050354

Abstract

The synthesis and properties of new chalcone ligand 4I-L ((2E)-1-[4-(1H-imidazol-1-yl)phenyl]-3-(4-iodophenyl)prop-2-en-1-one) and tetracoordinate Co(II) complex [Co(4I-L)2Cl2], (1a), are reported in this article. Upon recrystallization of 1a, the single crystals of [Co(4I-L)4Cl2]·2DMF·3Et2O (1b) were obtained and crystal structure was determined using X-ray diffraction. The non-covalent interactions in 1b were thoroughly analyzed and special attention was dedicated to interactions formed by the peripheral iodine substituents. The density functional theory (DFT), atoms in molecule (AIM) and noncovalent interaction (NCI) methods and electronic localization function (ELF) calculations were used to investigate halogen bond formed between the iodine functional groups and co-crystallized molecules of diethyl ether.

Highlights

In molecular crystals, the building blocks, molecules, are held together by various directional and non-directional non-covalent intermolecular interactions
In this work we explored approach (b) by using bulky monodentate ligands derived from chalcones of 40 -(imidazol-1-yl)acetophenone containing peripheral groups allowing formation of non-covalent interactions such as hydrogen or halogen bonding [29,30]
L)4Cl2]·2DMF·3Et2O (1b), (Et2O stands for diethylether), the crystal structure of which was determined chalcone ligand was prepared by aldol condensation of 40 -(imidazol-1-yl)acetophenone usingThe single-crystal

Summary

Introduction

The building blocks, molecules, are held together by various directional and non-directional non-covalent intermolecular interactions. Some of these interactions have been widely explored, such as hydrogen bonding, cation/anion···π or π ···π interactions [1,2,3,4,5], but non-conventional interactions such as tetrel [6], pnictogen [7], chalcogen [8] and halogen bonding [9,10] have been less extensively studied [11,12]. We discovered a new type of magnetic exchange pathway engaging Co···π interactions [23] and revealed possible influence of hydrogen bonding on occurrence of spin-crossover phenomenon [24]. In this report we focused our attention on interplay between halogen bonding and structure of mononuclear Co(II)

Methods

Findings

Discussion

Conclusion