Synthesis, crystal structure, vibrational, optical properties, thermal analysis and theoretical study of a new Sn(IV) complex (C5H14N2)2[SnCl6]2·5H2O

Abstract

In this study, a new organic-inorganic hybrid metal compound (C5H14N2)2[SnCl6]2.5H2O was crystallized at room temperature in the orthorhombic system (space group P21 21 21) where the structure is determined by single crystal X-ray diffraction analysis. The examination of the structure shows the cohesion and stability of the atomic arrangement result from the establishment of N—H···Cl, O(W)—H(W)···Cl, N—H···O(W) and O(W)—H(W)···O(W) hydrogen bonds between 1-methylpiperazine-1,4-diium (C5H14N2)2+cations, isolated (SnCl6)2– anions and water molecules to form organic and inorganic layers parallel to the (a, c) plane and alternate along the b-axis. Hirshfeld surface analysis was used to investigate intermolecular interactions, as well 2D fingerprint plots were conducted to reveal the contribution of these interactions in the crystal structure quantitatively. The solid phase FTIR and FT-Raman spectra of this compound have been recorded in the regions 400–4000 and 100–500 cm−1, respectively. The vibrational frequencies were also predicted from the calculated intensities by DFT method and were compared with the experimental frequencies, which yield good agreement between observed and calculated frequencies. Besides, the optical proprieties were investigated by UV-visible and photoluminescence spectroscopy studies in the region 200–700 nm and the electronic properties HOMO and LUMO energies were measured by TD-DFT approach. Moreover, this compound was characterized by thermal analysis between 300 and 500 K which revealing two phase transitions. Finally, X-ray photoelectron spectroscopy (XPS) analysis is reported to determine the degree of oxidation of tin in this compound and analyzing the surface chemistry of (C5H14N2)2[SnCl6]2.5H2O.