Mondal Antu, Chattopadhyay Shyamal Kumar
Department of Chemistry, Indian Institute of Engineering Science and Technology, Shibpur, Howrah711103, India.
ACS Omega. 2022 Nov 4;7(45):40941-40949. doi: 10.1021/acsomega.2c04063. eCollection 2022 Nov 15.
Cyanide is a very toxic pollutant to aquatic life and the environment. Analytical methods for the quantitative assay of cyanide, which are rapid, sensitive (low limit of detection), and cost-effective, are in great demand. Colorimetric and fluorometric methods are ideally suited for this purpose. In this report, we describe a Ni(II) complex containing a pyridoxal platform for the rapid and sensitive fluorometric estimation of cyanide. The square-planar Ni(II) complex, [Ni(L)(N)]·3HO, where the ligand LH = 4-[(2-dimethylamino-ethylimino)-methyl]-5-hydroxymtheyl-2-methyl-pyridin-3-ol, a Schiff base formed between pyridoxal and (2-dimethylamino)ethyl amine, was synthesized and characterized by various spectroscopic techniques as well as by single-crystal X-ray structure determination. The complex was found to selectively bind CN in the presence of other biologically important anions such as F, Cl, Br, I, OAc, S, NO , PO , SO , and HPO in tris-HCl/NaCl buffer [pH = 7.4], and it can be monitored by fluorescence turn-on or by UV-visible spectroscopy. The binding constant of the complex with CN was estimated to be 2.046 × 10 M and the limit of detection (LOD) was 9 nM, the LOD being considerably lower than the maximum permissible level of cyanide ions (1.9 μM) in drinking water, as recognized by the World Health Organization (WHO). The effects of pH and temperature on the sensing are also investigated. The Ni(II) complex is also found to bind to calf-thymus DNA very strongly, and the apparent binding constant ( ) was determined to be 1.33 × 10 M by the fluorescence quenching of the ethidium bromide-DNA adduct by the complex.
氰化物是对水生生物和环境毒性极强的污染物。对于氰化物定量分析的快速、灵敏（低检测限）且经济高效的分析方法需求极大。比色法和荧光法非常适合此目的。在本报告中，我们描述了一种含有吡哆醛平台的镍（II）配合物，用于快速灵敏地荧光测定氰化物。合成了平面正方形镍（II）配合物[Ni(L)(N)]·3H₂O，其中配体L⁻H = 4 - [(2 - 二甲基氨基 - 乙基亚氨基)-甲基]-5 - 羟甲基 - 2 - 甲基 - 吡啶 - 3 - 醇，是吡哆醛与（2 - 二甲基氨基）乙胺形成的席夫碱，并通过各种光谱技术以及单晶X射线结构测定对其进行了表征。发现在三羟甲基氨基甲烷 - 盐酸/氯化钠缓冲液[pH = 7.4]中，该配合物在其他生物学重要阴离子如F⁻、Cl⁻、Br⁻、I⁻、OAc⁻、S²⁻、NO₃⁻、PO₄³⁻、SO₄²⁻和HPO₄²⁻存在下能选择性结合CN⁻，并且可以通过荧光开启或紫外可见光谱进行监测。该配合物与CN⁻的结合常数估计为2.046×10⁵ M，检测限（LOD）为9 nM，该检测限远低于世界卫生组织（WHO）认可的饮用水中氰化物离子的最大允许水平（1.9 μM）。还研究了pH和温度对传感的影响。还发现镍（II）配合物与小牛胸腺DNA结合非常强烈，通过该配合物对溴化乙锭 - DNA加合物的荧光猝灭测定其表观结合常数（K）为1.33×10⁵ M。
