Gas and crystal structures of CCl2FSCN

Yanina Berrueta Martínez,Lucas S Rodríguez Pirani,Mauricio F Erben,Roland Boese,Christian G Reuter,Yury V Vishnevskiy,Norbert W Mitzel,Carlos O Della Védova

doi:10.1016/j.molstruc.2016.03.097

Abstract

Dichlorofluoromethyl thiocyanate, CCl2FSCN, was structurally studied in the solid and in the gas phase by means of single-crystal X-ray (XRD) and gas electron diffraction (GED), respectively. In the gas phase the title molecule adopts two stable conformers, described by the FC–SC dihedral angle. The gauche-conformer (FC bond with respect to the SC bond) is more stable than the anti-conformer. In this work we present the first experimental evidence for the existence of the anti-CF2ClSCN form. In the solid state only the most stable gauche-conformer was found. Intermolecular interactions were detected in the crystal structure and analyzed. A structural comparison of the results with those of related species as CCl2FSCN, CCl3SCN and CH2ClSCN is presented.

Highlights

The family of thiocyanate compounds is under permanent investigation
The crystal structure of CCl2FSCN contains solely the gaucheconformer while in the gas phase both gauche- and anti-conformations are present in equilibrium at room temperature, with the
The C^N bond lengths remain almost constant in CH2ClSCN, CCl3SCN and CCl2FSCN in the gas phase (re 1⁄4 1.160(5), 1.158(9), 1.160(5) Å), but they differ markedly from the solid-state values (1.145(5), 1.144(6), 1.144(9) Å, all 3 e.s.d.s), which themselves as a group are similar

Summary

Introduction

The family of thiocyanate compounds is under permanent investigation. Some experimental IR and Raman spectroscopy data as well as theoretical investigations for this species have been reported twenty years ago by our group [1]. GaucheCCl2FSCN was experimentally detected by means of Raman polarization measurements supplemented by computational chemistry calculations. The anti-conformer could only be computed by quantum-chemical calculations. Experimental support for the less stable anti-conformer is provided by the gas phase electron diffraction study presented in this work. X-ray diffraction measurements allow determining the crystal structure of the less symmetric and more abundant gauche-conformer. Some intermolecular interactions in terms of geometrical parameters involving halogen and chalcogen atoms have been determined. A comparison of the gas and crystal-phase structures between CCl2FSCN, CCl3SCN [2] and. CH2ClSCN [3] is presented

Synthesis

Instrumentation and procedure

Computational chemistry

Molecular structure in the gas phase

Molecular structure in the solid state and intermolecular contacts

Conclusion