ACTA

Triplet States in DOPA-Melanin and in Its Complexes with Kanamycin and Copper Cu(II) Ions

L. Najder-Kozdrowska^a, B. Pilawa^b, E. Buszman^c, A.B. Więckowski^a, L. Świątkowska^d, D. Wrześniok^c and W. Wojtowicz^a
^aDivision of Spectroscopy of Functional Materials, Institute of Physics, Faculty of Physics and Astronomy, University of Zielona Góra, Szafrana 4a, 65-516 Zielona Góra, Poland
^bDepartment of Biophysics
^cDepartment of Pharmaceutical Chemistry
^dDepartment of Instrumental Analysis, School of Pharmacy, Medical University of Silesia, Sosnowiec, Poland

Received: February 3, 2010; in final form: September 9, 2010

Full Text PDF

The mono- and biradical forms of DOPA-melanin (DOPA-eumelanin) were studied by EPR spectroscopy in 100-300 K temperature range. The existence of triplet states in DOPA-melanin was proved. The analysis of EPR spectra has shown that in DOPA-melanin and its complexes with kanamycin and Cu²⁺ ions, two kinds of paramagnetic centres exist. The first of them are in doublet ground state with spin S = 1/2 and they obey the Curie law. The paramagnetic centres of the second group are in thermally excited triplet state with spin S = 1 and in this case the Curie law is not fulfilled.

DOI: 10.12693/APhysPolA.118.613
PACS numbers: 61.66.Hq, 76.30.Rn, 87.64.kh