Zinc( ii ) and cadmium( ii ) carboxyphosphonates with a 3D pillared-layered structure: synthesis, crystal structures, high thermal stabilities and luminescent properties

• Published in: RSC advances Vol. 3; no. 2; pp. 623 - 631
• Main Authors: Chu, Wei, Zhu, Yan-Yu, Sun, Zhen-Gang, Jiao, Cheng-Qi, Li, Jing, Sun, Shou-Hui, Tian, Hui, Zheng, Ming-Jing
• Format: Journal Article
• Language: English
• Published: 01.01.2013
• Subjects: Crystal structure; Dimers; Helical; Interconnection; Ligands; Tetrahedrons; Three dimensional; Two dimensional
• ISSN: 2046-2069; 2046-2069
• DOI: 10.1039/C2RA22571A

Two novel divalent metal carboxyphosphonates with a 3D pillared-layered structure, [Zn(HL)] (1) and [CdCl(H sub(2)L)] (2) (H sub(3)L = 4-HOOCC sub(6)H sub(4)CH sub(2)NHCH sub(2)PO sub(3)H sub(2)), have been synthesized under hydrothermal conditions. Compounds 1 and 2 both feature three-dimensional (3D) framework structures with two-dimensional (2D) inorganic layers pillared by H sub(3)L. In compound 1, each {ZnO sub(4)} tetrahedron is linked viacorner-sharing by three {CPO sub(3)} tetrahedra to form a two-dimensional (2D) inorganic layer in the ac-plane. The adjacent layers are further pillared by the organic backbone {-C sub(6)H sub(4)CH sub(2)NHCH sub(2)-} of the carboxyphosphonate ligand, generating a 3D pillared-layered structure. For compound 2, each Cd(ii) cation is six-coordinated, and the interconnection of two {CdCl sub(2)O sub(4)} octahedra forms a dimer viaedge-sharing. The dimers are interconnected by {CPO sub(3)} tetrahedra viacorner-sharing to form a 2D inorganic layer in the ab-plane. Such neighboring 2D inorganic layers are further cross-linked through the organic pillars of the carboxyphosphonate ligand, thus resulting in a 3D pillared-layered structure. An interesting feature of compounds 1 and 2 is the presence of alternate left- and right-handed helical chains in their structures. It is of note that two title compounds are both stable up to high temperature. The luminescent properties of compounds 1 and 2 have also been studied.