Effect of pH on the self-assembly of three Cd(II) coordination compounds containing 5-(4-pyridyl)tetrazole: syntheses, structures, and properties

• Published in: Journal of coordination chemistry 2015-05, Vol.68 (10), p.1705-1718
• Main Authors: Meng, Gao-Xiang, Feng, Ya-Min, Wang, Yin, Gao, Yong-Li, Wan, Wen-Wu, Huang, Xin-Tang
• Format: Article
• Language: English
• Subjects: Cadmium(II); Coordination compounds; Coordination polymer; Cycloaddition; Fluorescence; Forming; In situ synthesis; pH dependent; Photoluminescence; Self assembly; Three dimensional
• ISSN: 0095-8972; 1029-0389
• DOI: 10.1080/00958972.2015.1024668

Hydrothermal reactions of CdSO 4 , 4-cyanopyridine, and sodium azide yield three metal coordination compounds via controlling the pH, [Cd 2 (4-ptz)(SO 4 )(OH)(H 2 O) 2 ](H 2 O) (1) [Cd 2 (4-ptz)(SO 4 )(OH)(H 2 O)] n (2), and known [Cd 2 (4-ptz) 2 (H 2 O) 4 ](H 2 O) 2 (3) (4-ptz = 5-(4-pyridyl)tetrazole). The in situ [2 + 3] cycloaddition reaction of nitrile and azide in the presence of Cd(II) produces the multidentate 4-ptz in these compounds. X-ray diffraction results indicate that metal centers in 1 are linked by 4-ptz - , , and OH − in their respective μ 5 -, μ 2 -, μ 3 -bridging modes, forming a 3-D coordination polymer. For 2, although the same raw materials are used, the component anions are linked to Cd(II) centers in completely different ways, i.e. for 4-ptz − in μ 3 −, in μ 5 -, and OH − in μ 3 -bridging modes, forming another 3-D coordination network. Thermal stabilities and photoluminescent properties of 1 and 2 have also been investigated. Three cadmium(II) coordination compounds were synthesized via controlling the pH in the in situ [2 + 3] cycloaddition reaction of CdSO 4 , 4-cyanopyridine, and sodium azide under hydrothermal treatment. Mononuclear 3 was obtained at weak acid solution pH 6.0~7.0, but 3-D coordination polymers 1 and 2 were preferred in weak alkaline conditions from pH 7.0 to 9.0.