Luminescent Properties of Twelve Novel MOFs Based on 2,7-Bis(4-benzoic acid)-N-(4-benzoic acid)Carbazole and Their Application in Ni2+ Ions Concentration Sensing and Vis-NIR Fluorescent Materials

Abstract

I will present twelve novel luminescent metal-organic frameworks, TCZ-001 – TCZ-005 and TCZ-M (M = Nd, Sm, Eu, Gd, Tb, Dy, Ho). All of the twelve MOFs were assembled from a novel luminescent carbazole-based ligand, 2,7-bis(4-benzoic acid)-N-(4-benzoic acid)carbazole. TCZ-001, TCZ-003 and TCZ-004 show a remarkable response to the Ni2+ concentration in DMA, H2O or EtOH. Some of Zn2+ ions were replaced by Ni2+ ions and the rate of the transmetalation depended on the concentration of Ni2+ ions. Also, changing part of the metal node would transform the colour of emitted light. Additionally, the colour of the luminescence displays a linear correlation with the Ni2+ concentration range from 0.005 M to 0.35 M (mol·L−1). Besides selective sensing of Ni2+, TCZ-004 can also be utilized to detect Eu3+ ions in DMA solution. Thus, several potential sensory probe materials for Ni2+ and Eu3+ detection in DMA solution have been obtained. As to TCZ-M (M = Nd, Sm, Eu, Gd, Tb, Dy, Ho), X-ray crystallography showed that all of them are isomorphous and possess a 3,6-connected three-dimensional (3D) framework with a point symbol of {4·62}2·{42·610·83}. The photoluminescence measurement indicates that TCZ-Eu shows reddish-orange emission bands and TCZ-Sm shows both visible and near-infrared (NIR) emission bands. In addition, the isomorphous structure of TCZ-M (M = Nd, Sm, Eu, Gd, Tb, Dy, Ho) provide the potential to fabricate multicolour luminescent materials. [1] D.-H. Chen, L. Lin, T.-L. Sheng, Y.-H. Wen, S.-M. Hu, R.-B. Fu, C. Zhuo, H.-R. Li and X.-T. Wu, CrystEngComm, 2017, 19, 2632. [2] D.-H. Chen, L. Lin, T.-L. Sheng, Y.-H. Wen, X.-Q. Zhu, L.-T. Zhang, S.-M. Hu, R.-B. Fu and X.-T. Wu, New J. Chem., 2018, 42, 2830.