Synthesis, characterisation and cytotoxicity studies of Manganese(I) and Rhenium(I) based metallacrown ethers

Manganese(I) and Rhenium(I) based metallacrown ethers [M(CO)(3)Br(mu-pcatgd)] (1, M = Mn; 2, M = Re) were synthesised by the reaction of M(CO)(5)Br (M = Mn, Re) and pyridine appended bidentate ligand crafted with flexible polyether spacer. The self-assembled mononuclear compounds 1 and 2 were characterised by IR, NMR, UV-Visible absorption and emission spectroscopic techniques. Molecular structure of 2 was determined by single-crystal X-ray diffraction methods and the molecular masses of 1 and 2 were confirmed by ESI-mass spectrometry. Anticancer activities of compounds 1 and 2 were investigated by in vitro cytotoxicity studies against different cancer cell lines as well as on normal cells. Compounds 1 and 2 showed a broad-spectrum inhibition on few cancer cells that were comparable to cisplatin. Compound 1 exhibited selective inhibition of cancer cells upon irradiation at lambda(max) 365 nm in dose-dependent manner. Morphological studies showed the induction of apoptosis in compound 1-treated cancer cells upon irradiation. The UV-Visible absorption spectroscopy-based myoglobin assay further supported the nature of compound 1 as photoactivatable CO releasing molecule (PhotoCORM). (C) 2015 Elsevier B.V. All rights reserved.