New cobalt (II) complexes of '3-acetyl-4-hydroxy-2H-chromene-2one': Crystal structure and Hirshfeld surface analysis, fluorescence behaviour and antioxidant activity

Two novel transition metal coumarin complexes 'trans-di-aqua-bis (3-acetyl-4-hydroxy-2H-chromen-2-one) Co (II) dihydrate' (hydco) of the formula C22H14CoO8.4(H2O) and 'trans-di-ethanol-bis (3-acetyl-4-hydroxy-2H-chromen-2-one) Co (II)' (nonhydco) of the formula C(22)H(14)CoO(8.)4(H2O) were synthesized and their structures were characterized by different spectroscopic methods (IR, UV-VIS and fluorescence). Crystal structures of mentioned compounds were solved either from single-crystal at T = 120 K or from powder diffraction data. Further, the Hirshfeld surface analysis and fingerprints reveal that the structure of the non-hydrated complex is dominated by H-H (51%) and O-H/H-O (24.2%) contacts. The structure of the hydrated complex shows that the H-H (26.8%) and O-H/H-O (26.4%) contacts, make the greatest contribution to the Hirshfeld surfaces. Antioxidant tests indicate that the two new hydrated and unhydrated complexes are an effective against the DPPH radicals with very close IC50 values around 0.022 mu mol/L and 0.021 mu mol/L respectively. The fluorescence behaviours of doped poly (methyl methacrylate) (PMMA) with the non-hydrated complex were studied. (C) 2018 Elsevier B.V. All rights reserved.