Solvothermal preparation of luminescent zinc(II) and cadmium(II) coordination complexes based on the new bi-functional building block and photo-luminescent sensing for Cu2+, Al3+ and L-lysine

[Display omitted] •Two new coordination complexes based on 4′-(1H-1,2,4-triazole-1-yl)-[1,1′-biphenyl]-4-carboxylic acid have been synthesized.•Photo-luminescent experiment reveals that 1 can accurately recognize Al3+ and Cu2+with excellent selectivity and sensitivity.•1 can recognize L-lysine with excellent sensitivity (Ksv = 4.9118 × 104 [M]−1). In industry, over usage of Cu2+ and Al3+ will lead to toxic wastewater, which further to give serious pollution for the environment. On the other hand, L-lysine can enhance serotonin release in the amygdala, with subsequent changes in psychobehavioral responses to stress. Therefore it is the urgent problem to design a method for detecting the amount of Cu2+, Al3+, and L-lysine. In this work, through the solvothermal synthesis method, two new coordination complexes based on the new bifunctional building block 4′-(1H-1,2,4-triazole-1-yl)- [1,1′-biphenyl]-4-carboxylic acid (HL) have been synthesized, namely, [Zn(L)2·4H2O] (complex 1) and [Cd(L)2·4H2O] (complex 2). X-ray single-crystal diffractometer was used to analyze its structure, powder X-ray diffraction (PXRD) patterns confirmed that 1 and 2 powder’s purity and 1 can keep stable during the detection process of Cu2+, Al3+, and L-lysine, respectively. Elemental analysis, thermogravimetric analysis, infrared analysis, ultraviolet analysis and fluorescent spectrum have been used to characterize these complexes. The photo-luminescent test showed that 1 can accurately recognize Al3+ and Cu2+ among various cations. On the other hand, 1 can distinguish L-lysine among amino acid molecules. Therefore, 1 can be utilized as a multifunctional fluorescent probe for Al3+(Ksv = 1.5570 × 104 [M]−1), Cu2+(Ksv = 1.4948 × 104 [M]−1) and L-lysine (Ksv = 4.9118 × 104 [M]−1) with low detection limits (17.5 μM, 18.2 μM, 5.6 μM) respectively.