Department of Chemistry, University of Calcutta, 92 A. P. C. Road, Kolkata 700009, India.
Inorg Chem. 2012 Aug 20;51(16):8739-49. doi: 10.1021/ic300412u. Epub 2012 Aug 7.
The work in the present investigation reports the syntheses, structures, steady state, and time-resolved photophysical properties of a tetraiminodiphenol macrocyclic ligand H(2)L and its eight dinuclear zinc(II) complexes and one cadmium(II) complex having composition Zn(2)L(H(2)O)(2)(2)·2CH(3)CN (1), Zn(2)L(H(2)O)(2)(2)·2dmf (2), Zn(2)L(H(2)O)(2)(2)·2dmf (3), [Zn(2)LCl(2)] (4), [Zn(2)L(N(3))(2)] (5), [Zn(2)L(NCS)(2)] (6), [Zn(2)L(NCO)(2)] (7), Zn(2)L(NCSe)(2)·dmf (8), and [Cd(2)L(OAc)(2)] (9) with various coordinating and noncoordinating anions. The structures of all the complexes 1-9 have been determined by single-crystal X-ray diffraction. The noncovalent interactions in the complexes result in the generation of the following topologies: two-dimensional network in 1, 2, 4, 6, 7, 8, and 9; three-dimensional network in 5. Spectrophotometric and spectrofluorometric titrations of the diprotonated salt H(4)L(2) with triethylamine as well as with zinc(II) acetate and cadmium(II) acetate have been carried out, revealing fluorescence enhancement of the macrocyclic system by the base and the metal ions. Steady state fluorescence properties of H(4)L(2) and 1-9 have been studied and their quantum yields have been determined. Time resolved fluorescence behavior of H(4)L(2) and the dizinc(II) and dicadmium(II) complexes 1-9 have also been studied, and their lifetimes and radiative and nonradiative rate constants have been determined. The induced fluorescence enhancement of the macrocycle by zinc(II) and cadmium(II) is in line with the greater rate of increase of the radiative rate constants in comparison to the smaller rate of increase of nonradiative rate constants for the metal complexes. The fluorescence decay profiles of all the systems, being investigated here, that is, H(4)L(2) and 1-9, follow triexponential patterns, revealing that at least three conformers/components are responsible to exhibit the fluorescence decay behavior. The systems and studies in this report have been compared with those in the reports of the previously published similar systems, revealing some interesting aspects.
本研究报告合成、结构、稳态和时间分辨光物理性质的四亚氨基二苯酚大环配体 H(2)L 及其八个双核锌（II）配合物和一个镉（II）配合物，具有组成 Zn(2)L(H(2)O)(2)(2)·2CH(3)CN（1）、Zn(2)L(H(2)O)(2)(2)·2dmf（2）、Zn(2)L(H(2)O)(2)(2)·2dmf（3）、[Zn(2)LCl(2)]（4）、[Zn(2)L(N(3))(2)]（5）、[Zn(2)L(NCS)(2)]（6）、[Zn(2)L(NCO)(2)]（7）、Zn(2)L(NCSe)(2)·dmf（8）和[Cd(2)L(OAc)(2)]（9），具有各种配位和非配位阴离子。所有配合物 1-9 的结构均通过单晶 X 射线衍射确定。配合物中的非共价相互作用导致产生以下拓扑结构：二维网络在 1、2、4、6、7、8 和 9 中；三维网络在 5 中。用三乙胺以及锌（II）醋酸盐和镉（II）醋酸盐对二质子化盐H(4)L(2)进行了分光光度和分光荧光滴定，表明大环体系的荧光增强由碱和金属离子引起。研究了H(4)L(2)和 1-9 的稳态荧光性质，并确定了它们的量子产率。还研究了H(4)L(2)和二锌（II）和二镉（II）配合物 1-9 的时间分辨荧光行为，并确定了它们的寿命和辐射和非辐射速率常数。与较小的非辐射速率常数相比，锌（II）和镉（II）对大环的诱导荧光增强与辐射速率常数的较大增加一致。这里研究的所有系统，即H(4)L(2)和 1-9 的荧光衰减曲线遵循三指数模式，表明至少有三个构象/组件负责表现出荧光衰减行为。与之前发表的类似系统的报告中的系统和研究进行了比较，揭示了一些有趣的方面。
