Transition metal phosphonates with pyridyl-based phosphonic acids: synthesis, characterization and luminescence properties

Abstract

Two transiton metal phosphonates, Cd₂[OOCC₅H₃NPO₃H]₂·H₂O (1) and Zn[OOCC₅H₄NPO₃]·H₂O (2), were synthesized by hydrothermal reactions. Single-crystal X-ray diffraction analyses show that both have a 3-D framework. In 1, the asymmetric [Cd–NO₅] octahedron is connected to the [P–CO₃] tetrahedron through corner sharing and two neighboring [Cd–NO₅] octahedra are bridged via a mutual plane [O1–O2–O3]. Compound 2 has a scales-like multilayer structure viewing from b and c. [Zn–O₄] tetrahedra linked [P–CO₃] tetrahedra through corner O sharing. The thermogravimetric properties and luminescence spectra of 1 and 2 were investigated. Compound 2 emitted a purple-blue light upon 323 nm excitation. Above 100 nm, red shifts in both compounds make them candidates for luminescent materials.

Keywords:

• Metal phosphonates
• transition phosphonates
• luminescence
• 5-phosphononicotinic acid
• Cd(II)
• Zn(II)