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

• Published in: Journal of molecular structure 2018-12, Vol.1173, p.574-582
• Main Authors: Bejaoui, Linda, Rohlicek, Jan, Ben Hassen, Rached
• Format: Article
• Language: English
• Subjects: Ab-initio structure determination; Antioxidant activity; Co II complex; Coumarin ligand; Fluorescence; Hirshfeld surfaces
• ISSN: 0022-2860; 1872-8014
• DOI: 10.1016/j.molstruc.2018.07.017

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 C22H14CoO8 0.2 (C2 H6O) 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 HH (51%) and OH/HO (24.2%) contacts. The structure of the hydrated complex shows that the HH (26.8%) and OH/HO (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 μmol/L and 0.021 μmol/L respectively. The fluorescence behaviours of doped poly (methyl methacrylate) (PMMA) with the non-hydrated complex were studied. [Display omitted] •Complexes resulted from Co(C2H3O2)2 and 3-acetyl-4-hydroxycoumarin in two solvents.•Structural study was performed by single crystal X-ray diffraction at T = 120 K.•Hirshfeld surfaces reveal structure is dominated by HH and OH/HO contacts.•Hydrated and unhydrated complexes are effective antioxidants against the DPPH radicals.•Fluorescence quenching phenomenon is inhibited when increasing the dopant in PMMA.