Anion-directed structural tuning of two azomethine-derived Zn complexes with optoelectronic recognition of Cu in aqueous medium with anti-cancer activities: from micromolar to femtomolar sensitivity with DFT revelation

• Published in: Dalton transactions : an international journal of inorganic chemistry 2023-08, Vol.52 (32), p.1113-11142
• Main Authors: Pandit, Nithun Ranjan, Bej, Sourav, Das, Riyanka, Ghosal, Nirajan, Mondal, Ananya, Pal, Ranjana, Ghosh, Meenakshi, Banerjee, Priyabrata, Biswas, Biplab
• Format: Article
• Language: English
• ISSN: 1477-9226; 1477-9234
• DOI: 10.1039/d3dt01901b

Herein, two novel mononuclear transition metal Zn 2+ complexes i.e. [Zn(HL)(N 3 )(OAc)] ( NS-1 ) & [Zn(HL) 2 (ClO 4 ) 2 ] ( NS-2 ) have been synthesised using a tridentate clickable Schiff base ligand, HL (2-methyl-2-((pyridin-2-ylmethyl)amino)propan-1-ol), and the polyatomic monoanions N 3 − and ClO 4 − for NS-1 and NS-2 respectively. Interestingly, NS-1 and NS-2 have been explored for the detection of Cu 2+ with an LOD of 48.6 fM (response time ∼6 s) and 2.4 μM respectively through two mutually independent pathways that were studied using sophisticated methods like UV-Vis, cyclic voltammetry, ESI-MS etc. with theoretical DFT support. Herein, both chemosensors are equally responsive towards the detection of Cu 2+ in aqueous as well as other targeted real field samples with appreciable recovery percentage (74.8-102%), demonstrating their practical applicability. Moreover, the detection of unbound Cu 2+ in a human urine specimen was also analysed which may be helpful for the diagnosis of Cu 2+ -related disorders like Wilson's disease. Taking one step ahead, TLC strips have been employed for on-field detection of the targeted analytes by contact mode analysis. Additionally, the anti-cancer activity of these complexes has also been studied on breast cancer cells with the help of the MTT assay. It has been found that at a 0.5 mM dose, both NS-1 and NS-2 could kill 81.4% and 73.2% of cancer cells respectively. However, it has been found that NS-1 destroys normal cells together with cancer cells. Hence, NS-2 could be administered as a better anticancer drug for MDA-MB-231 cancer cells in comparison with NS-1 . In a nutshell, the present work describes how anion-directed synthesis of two architecturally different metal complexes leads toward the detection of the same analyte via an independent chemodosimetric pathway along with their anti-cancer activities on breast cancer cells. Herein, two novel mononuclear transition metal Zn 2+ complexes have been synthesised using a tridentate clickable Schiff base ligand, HL (2-methyl-2-((pyridin-2-ylmethyl)amino)propan-1-ol) and the polyatomic monoanions N 3 − and ClO 4 − .