Syntheses and structural characterizations of six ionic inorganic-organic salts from heterocyclic aromatic bases and tetrachlorometallates of Zn, Cu and Cd

Abstract

Six organic-inorganic hybrid salts, ([(HL1)₂(CdCl₄)(H₂O)] (1) (L1 = 2-(imidazol-1-yl)-1-phenylethanone), [(HL2)₂(ZnCl₄)(H₂O)] (2) (L2 = 6-bromobenzo[d]thiazol-2-amine), [(H₂L3)₂(CdCl₄)₂(CH₃OH)] (3) (L3 = bis(N-imidazolyl)methane), [(H₂L4)(ZnCl₄)(H₂O)₂] (4) (L4 = bis(N-imidazolyl)butane), [(H₂L5)₂(CuCl₄)₂]·7H₂O (5) (L5 = di(2-benzimidazol-1-ylethyl)ether) and [(H₂L6)₄(ZnCl₄)₄]·7H₂O (6) (L6 = 1,2-bis(2-benzimidazolyl)-1,2-ethanediol)), were prepared and characterized by IR, XRD, EA and TG analyses. The aryl rings of the cations in all salts are essentially planar. XRD analysis indicated that all of the complexes are built from non-covalent bonds between the cations and the tetrachlorometallate anions. The lattice solvent (H₂O/CH₃OH) molecules also played crucial roles in structure extension of all salts. Extensive intermolecular interactions have been used in the self-assembly of motifs, ranging from strong X-H···Y (X = O, N; Y = Cl, O) H-bonds to weak CH···A (A = O, Cl, Br), CH₂···A (A = O, Cl), O···O, Cl···O, Cl···S, Cl···π, Br···Cl, CH₃···π and π···π associations. 3 D architectures are found in 1 and 3-6, but only a 2 D architecture appeared in 2. The arrangements of the anions and cations in the solid are governed not only by the size and symmetry of the cations, but also by the non-covalent bonds in the crystal structures.

Graphical Abstract

Keywords:

• Zinc
• copper
• cadmium
• crystal structure
• heterocyclic aromatic bases
• inorganic–organic hybrid

Acknowledgement

We gratefully acknowledge the financial support of the Zhejiang Provincial Natural Science Foundation of China.

Disclosure statement

The authors declare no competing financial interest..