The global minimum optimized structures of the free sensor 5-methyl-4-(2-thiazolylazo) resorcinol (5-Me-TAR) and 5-Me-TAR-Cu2+ complexes in the gas phase have been investigated by using Density Functional Theory (DFT) with the def2-TZVP basis set. To compare the selectivity of 5-Me-TAR for metal ions, the binding energy of 5-Me-TAR with various metal ions (Na+, K+, Mg2+, Ca2+, Ba2+, Mn2+, Co2+, Ni2+, Cu2+, Zn2+, Pd2+, Cd2+ and Hg2+) were calculated at the same level as the theory. Binding energy values of most transition metal ions are lower than alkaline earth metal ions and alkali metal ions, respectively. The 5-Me-TAR sensor shows the highest selectivity with the Cu2+ ion. Moreover, Dependent Density Functional Theory (TDDFT) results confirm that the 5-Me-TAR-Cu2+ complex is stabilized by the sensor to metal charge transfer process. The computational studies suggested that the 5-Me-TAR is suitable for Cu2+ ion detection sensor development.

中文翻译：

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5-methyl-4-(2-thiazolylazo) 间苯二酚作为金属离子传感器的结构和选择性的理论研究：DFT 计算

利用密度泛函理论研究了气相中游离传感器 5-methyl-4-(2-thiazolylazo) 间苯二酚 (5-Me-TAR) 和 5-Me-TAR-Cu2+ 配合物的全局最小优化结构。 DFT) 与 def2-TZVP 基组。为了比较 5-Me-TAR 对金属离子的选择性，5-Me-TAR 与各种金属离子（Na+、K+、Mg2+、Ca2+、Ba2+、Mn2+、Co2+、Ni2+、Cu2+、Zn2+、Pd2+、 Cd2+ 和 Hg2+) 的计算水平与理论相同。大多数过渡金属离子的结合能值分别低于碱土金属离子和碱金属离子。5-Me-TAR 传感器对 Cu2+ 离子的选择性最高。此外，相关密度泛函理论 (TDDFT) 结果证实 5-Me-TAR-Cu2+ 配合物通过传感器到金属的电荷转移过程稳定。