Synthesis, spectroscopic, CO‐releasing ability, and anticancer activity studies of [Mn(CO)3(L–L)Br] complexes: Experimental and density functional theory studies

Abstract

AbstractTwo different series of manganese(I) tricarbonyl complexes containing phosphine‐based (1–5) and 4′‐substituted 2,2′:6′,2″‐terpyridine‐based ligands (6–10) have been synthesized in order to study their CO‐releasing ability and to investigate their anticancer activity. All the synthesized complexes (1–10) have been fully characterized using standard spectroscopic and analytical techniques. Further 5, 7, and 9 have also been characterized by single‐crystal X‐ray diffraction studies. Although both the sets of ligands are π‐acceptors, they tend to change the Mn—CO bond strength upon complexation, thus affecting the CO release. Photoactivation of 1–5 and 6–10 has been achieved using 365 nm UV irradiation and low intensity visible light, respectively. The MnCO bond strength has been examined using the density functional theory (DFT) and time‐dependent DFT (TD‐DFT) calculations. In order to find the therapeutic viability of the visible light activated complexes, their cytotoxicity has been investigated both in the dark and under irradiation. The MTT (3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyl tetrazolium bromide) assay reveals the potential application of some of the synthesized complexes especially towards the lung cancer cells in the dark condition.