Synthesis, crystal structure, infrared spectroscopy and Hirshfeld surface analysis of cis-(thiocyanato-κN)(1,4,8,11-tetraazacyclotetradecane-κN⁴)chromium(III)(µ-1,3-thiocyanato-κN,S)trichloridozincate

Abstract

The crystal structure of cis-[Cr(NCS)(cyclam)(µ-NCS)ZnCl₃] (cyclam = 1,4,8,11-tetraazacyclotetradecane, C₁₀H₂₄N₄) was determined using synchrotron radiation at 100 K. The chromium(III) ion is coordinated by four N atoms of cyclam and two N-bonded NCS groups in a cis arrangement, displaying a distorted octahedral geometry while the coordination sphere of the zinc(II) ion is bonded by three Cl ions and one S atom from bridged thiocyanate group with a slightly distorted tetrahedral environment. One thiocyanato group N6–C12–S2 forms a µ-1,3-NCS bridge between Cr and Zn ions. The Cr–N(cyclam) bond lengths are in the range of 2.076(2) to 2.086(2) Å while mean Cr–N(NCS) and Zn–S(SCN) bond lengths are 1.997(2) and 2.3819(16) Å. The [Cr(NCS)₂(cyclam)]⁺ moiety in the complex adopts the cis-V configuration. The crystal structure is stabilized by intermolecular hydrogen bonds involving the cyclam N–H or C–H groups as donors and Cl ions of the ZnCl₃(SCN) unit or S atoms of NCS groups as acceptors. Hirshfeld surface analysis indicated that the H···Cl/Cl···H (36.1%), H···H (24.8%), H···S/S···H (23.8%) and H···C/C···H (5.2%) interactions contributed most importantly to the crystal packing. Infrared (IR) spectroscopic properties were also described.

Graphical Abstract

Keywords:

• Crystal structure
• Cr(III)-Zn(II) complex
• cyclam
• cis-V configuration
• thiocyanato groups
• IR spectroscopy
• Hirshfeld surface analysis

Disclosure statement

The authors declare that there is no conflict of interests regarding the publication of this article.

Additional information

Funding

This research was funded by the bilateral collaboration program (NRF [grant no. 2018K1A3A1A39065843]) between South Korea and Slovakia. The X-ray crystallography experiment at the PLS-II BL2DSMC beamline was supported in part by MSIT and POSTECH.