Insight into non-covalent interactions in a tetrachlorocadmate salt with promising NLO properties: Experimental and computational analysis

Abstract

This paper deals with the crystal structure of the new non-centrosymmetric organic-inorganic hybrid material, (C6H14N)2[CdCl4]. Single crystal X-ray diffraction analysis shows that this compound crystallizes in the orthorhombic system, with the space group Cmc21 and the following parameters a = 27.257 (2) Å, b = 8.3560 (6) Å, c = 7.8872 (5) Å, V = 1796.4 (2) Å3 and Z = 4. The structure provides a new interesting example of infinite inorganic chains of [CdCl5]n following the c→ crystallographic direction. The monoprotonated cyclohexylammonium cations are linked to the anions via electrostatic, multiple bifurcated N—H…Cl hydrogen bonds and van der Waals interactions. To support experimental results, DFT calculations have been accomplished via the B3LYP method with 6–311++G(d,p) and LANL2DZ basis set on molecular geometry, vibrational and electronic properties. The non-covalent interactions were studied through AIM and RDG analysis and quantitatively using the Hirshfeld surfaces (HS) associated with 2D fingerprint plots. The NLO properties have been also investigated by DFT and compared to the urea reference