Isostructural Inorganic-Organic Piperazine-1,4-diium Chlorido- and Bromidoantimonate(III) Monohydrates: Octahedral Distortions and Hydrogen Bonds.

Maciej Bujak,Dawid Siodłak

doi:10.3390/molecules25061361

Maciej Bujak, Dawid Siodłak

Open Access

https://doi.org/10.3390/molecules25061361

Copy DOI

Journal: Molecules (Basel, Switzerland)	Publication Date: Mar 17, 2020
Citations: 2	License type: CC BY 4.0

Affiliation: Opole University

Abstract

Halogenidoantimonate(III) monohydrates of the (C4H12N2)[SbX5]·H2O (X = Cl, 1 or Br, 2) formula, crystallizing in the same monoclinic space group of P21/n, are isostructural, with an isostructurality index close to 99%. The single crystal X-ray diffraction data do not show any indication of phase transition in cooling these crystals from room temperature to 85 K. Both hybrid crystals are built up from [SbX6]3– octahedra that are joined together by a common edge forming isolated bioctahedral [Sb2X10]4– units, piperazine-1,4-diium (C4H12N2)2+ cations and water of crystallization molecules. These structural components are joined together by related but somewhat different O/N/C–H···X and N–H···O hydrogen bonded systems. The evolution of structural parameters, notably the secondary Sb–X bonds along with the associated X/Sb–Sb/X–X/Sb angles and O/N/C–H···X hydrogen bonds, as a function of ligand exchange and temperature, along with their influence on the irregularity of [SbX6]3– octahedra, was determined. The comparison of packing features and hydrogen bond parameters, additionally supported by the Hirshfeld surface analysis and data retrieved from the Cambridge Structural Database, demonstrates the hierarchy and importance of hydrogen bond interactions that influence the irregularity of single [SbX6]3– units.

Highlights

The crystal structures of mixed inorganic–organic halogenidoantimonates(III) with organic cations are mainly based upon [SbX6 ]3– and [SbX5 ]2– polyhedra (X = Cl, Br or/and I) forming various types of inorganic substructures, and organic cations that are located between and/or within inorganic frameworks [1,2,3,4]
We found that the isostructural crystals of 1 and 2 could serve as a convenient system for investigating the structural consequences of the effect of halogen exchange on the polyhedral distortion in the group of antimony(III) compounds, because of their close relationship and simple inorganic substructure
The title monohydrates of piperazine-1,4-diium pentachloridoantimonate(III) and pentabromidoantimonate(III) were found to be isostructural—they crystallize in the same monoclinic system with the P21 /n space group and they are characterized by similar unit–cell parameters

Summary

Introduction

The crystal structures of mixed inorganic–organic halogenidoantimonates(III) with organic cations are mainly based upon [SbX6 ]3– and [SbX5 ]2– polyhedra (X = Cl, Br or/and I) forming various types of inorganic substructures, and organic cations that are located between and/or within inorganic frameworks [1,2,3,4]. It was found that the geometrical irregularities of antimony(III) polyhedra are related to interactions of these single inorganic units with both inorganic and organic components of the structure: (i) inorganic polyhedra may be joined together by bridging X atoms forming polyhedral infinitive or isolated units—primary deformation and (ii) organic cations may be hydrogen bonded to halogen ligands, changing their geometry relative to the central SbIII atom—secondary deformation [12,13,14,15]. It is noteworthy that the ferroic properties, in these compounds, have been limited to particular chemical stoichiometries, e.g., R3 Sb2 X9 (R—organic cation) [3,18,22,23,24,25,26,27,28,29]

Methods

Results

Conclusion