Georgieva, Ivelina and Trendafilova, Natasha and Creaven, Bernadette S. and Walsh, Maureen and Noble, Andy and McCann, Malachy (2009) Is the C=O frequency shift a reliable indicator of coumarin binding to metal ions through the carbonyl oxygen? Chemical Physics, 365. pp. 69-79.

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Abstract

The coumarin ligand, 4-hydroxy-3-nitro-2H-chromen-2-one (Hhnc) and its Cu(II) and Ag(I) complexes were studied by DFT calculations at B3LYP/B1 and PW91/B1 levels. MEP of the deprotonated ligand, hnc-, and energy calculations of model metal complexes predicted the ligand binding to the metal ion through the hydroxyl and the nitro oxygens in agreement with experiment. Based on precisely selected Cu/Ag model complexes with hnc-, a relation between the vibrational behaviour of the ligand donor groups and the ligand binding modes in the complexes was deduced. The observed carbonyl m(C=O) downshift (50–90 cm-1) is attributed to intermolecular H-bonding formed between the C@O group and lattice water molecules or due to the C@O binding to the metal ion in case of bridging coumarin ligand (in Aghnc). Much larger m(C=O) downshift (~220–240 cm-1) is predicted in case of monodentate or bidentate (with the nitro group) bonding of the carbonyl C=O group to the metal ion.

Item Type:	Article
Keywords:	Ag(I); Cu(II) complexes; Coumarin; DFT modeling; Electronic structure; IR spectra;
Academic Unit:	Faculty of Science and Engineering > Chemistry
Item ID:	9676
Depositing User:	Dr. Malachy McCann
Date Deposited:	13 Jul 2018 11:40
Journal or Publication Title:	Chemical Physics
Publisher:	Elsevier
Refereed:	Yes
URI:
Use Licence:	This item is available under a Creative Commons Attribution Non Commercial Share Alike Licence (CC BY-NC-SA). Details of this licence are available here

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