Effects of solvents and temperature on the luminescence properties of Cd-isonicotinic acid frameworks based on mono-, bi-, and trinuclear cluster units

• Published in: CrystEngComm 2014-01, Vol.16 (6), p.1113-1125
• Main Authors: Gao, Song, Fan, Rui-Qing, Qiang, Liang-Sheng, Wang, Ping, Chen, Shuo, Wang, Xin-Ming, Yang, Yu-Lin
• Format: Article
• Language: English
• Subjects: Clusters
• ISSN: 1466-8033; 1466-8033
• DOI: 10.1039/C3CE42216J

In this work, we present the synthesis of three novel 3D Cd(ii) coordination polymers, {[Cd(IN) sub(2)].H sub(2)O } sub(n) (1), [Cd sub(2)(IN) sub(2)(SO sub(4))(DMF) sub(2)] sub(n) (2) and {[Cd sub(3)(IN) sub(5.5)]. 0.5OH super(-)} sub(n) (3) (HIN = isonicotinic acid). Coordination polymers 1 and 2 were obtained via solvothermal reactions. The synthesis of coordination polymer 3 was realized by a simple temperature induced single crystal to single crystal transition from 1. Single-crystal X-ray diffraction analyses revealed that 1-3 exhibit three different structural types: 1 displays a (6,3)-connected rtl net with the Schlaefli symbol (4.6 super(2)) sub(2) (4 super(2).6 super(10).8 super(3)) constructed from mononuclear [CdO sub(4)N sub(2)] clusters with the help of HIN. 2 is defined as a 6-connected pcu net with the Schlaefli symbol {4 super(12).6 super(3)} which is built from binuclear [Cd sub(2)(SO sub(2)) sub(2 )] clusters and HIN linkers. 3 can be regarded as a 9-connected ncd net with the Schlaefli symbol {3 super(6).4 super(22).5 super(8)}, which consists of paddlewheel trinuclear [Cd sub(3)(O sub(2)C) sub(5 )] clusters and a bridging HIN. Coordination polymers 1-3 display luminescence with emission maxima containing deep blue, blue, light blue and green at 298 K or 77 K both in solvents (polarity: DMF > CH sub(3)OH > CH sub(2)Cl sub(2)) and in the solid state. The lifetime of all the molecules is in microsecond scale.