Naslov
A new cytosine-copper paramagnetic complex Spectroscopic study

Autori
Krilov, Dubravka ; Gomzi, Vjeran ; Herak, Janko N.

Izvornik
Spectrochimica Acta Part A - Molecular and Biomolecular Spectroscopy (1386-1425) 70 (2008), 5; 1238-1242

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, kratko priopcenje, znanstveni

Ključne riječi
Copper-cytosine complex; EPR; Cytosine monohydrate

Sažetak
Two different copper complexes with cytosine molecules are formed in the process of crystal growth from the aqueous solution with traces of copper. One of them is diamagnetic, turning into paramagnetic upon ionizing irradiation (complex I). The other, the subject of the present study, is paramagnetic (complex II) as prepared. For complex II, EPR spectra demonstrate that the copper ion is coordinated with one nitrogen atom and three oxygen atoms. On the basis of the detailed EPR spectroscopic analysis and quantum-chemical calculations (in the DFT approach) the model of the complex has been proposed. Both experimental data and the theoretical results support the model with the copper atom, located between the two cytosine ribbons, ligated to a nitrogen and an oxygen atom from two opposing cytosine molecules and two oxygen atoms from water molecules. For complex II the Raman spectra demonstrated concerted restructuring of the hydrogen bonding in the cytosine crystal matrix upon insertion of copper ions.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

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