Synthesis, structure and Hirshfeld surface analysis, vibrational and DFT investigation of (4-pyridine carboxylic acid) tetrachlorocuprate (II) monohydrate

[摘要] The new organic–inorganic hybrid compound [C$_6$H$_6$NO$_2$]$_2$CuCl$_4$$\cdot$H$_2$O has been grown from an aqueous mixture by the solvent evaporation method. X-ray diffraction, Hirshfeld surface analysis, FT-IR and FT-Raman spectroscopy were applied to characterize the composition and crystal structure of the complex. It is crystallized in a triclinic system ($P\bar{1}$ space group). The structure of this compound might be described as layered with two parallel anionic and cationic layers. The first layer is composed of isolated square planar [CuCl4]2− and the second layerof [C$_6$H$_6$NO$_2$]$^{2+}$. The water molecule is placed between the layers formed by organic cations along the $b$ axis. Network hydrogen-bonding and $\pi–\pi$ interactions lead to the formation of a three-dimensional architecture. Hirshfeld surface analysis for visually analysing intermolecular interactions in crystal structures employing molecular surfacecontours and 2D fingerprint plots has been used to scrutinize molecular shapes. The vibration properties of this structure were studied by IR spectroscopy and Raman scattering. Vibration spectra were also calculated theoreticallyby means of Gaussian 03 package of programs within the density functional theory (DFT) framework using the B3LYP/LanL2DZ level of theory. To sum up, good consistency is found between the calculated results on onehand and the IR and Raman spectra and experimental structure on the other. This study confirms the presence of the organic cations [C$_6$H$_6$NO$_2$]$^{2+}$, the inorganic anions [CuCl$_4$]$^{2−}$ and H$_2$O.

[学科分类] 材料工程

[关键词] Crystal structure;Hirshfeld surface;FT-IR;Raman;DFT/B3LYP/LanL2DZ.