KRISTALNA STRUKTURA I ANTIOKSIDATIVNA AKTIVNOST Cu(II)-KOMPLEKSA AZO PIRIDONSKE BOJE

Abstract

Heterociklične azo boje zauzimaju značajno mesto u oblasti koordinacione hemije, usled njihove široke upotrebe u elektrohemijskim i optičkim istraživanjima [1]. Sa drugestrane, kompleksi metala sa heterocikličnim ligandima imaju značajan biološki potencijal, jer ispoljavaju citotoksičnost, antimikrobnu i antioksidativnu aktivnost [2]. U ovom radu, azoboja na bazi piridona (5-(4-metoksifenilazo)-1-etil-3-cijano-6-hidroksi-4-metil-2-piridon, HL) je upotrebljena za kompleksiranje sa Cu(II)-jonima u N,N-dimetilformamidu (DMF) na sobnoj temperaturi. Dobijeni kompleks (CuL2(DMF)) je okarakterisan UV-Vis i ATR-FTIR spektroskopijom, kao i rendgenskom strukturnom analizom. Asimetrična jedinica kompleksa se sastoji iz jednog Cu(II)-atoma, dva helatna L-liganda i jednog koordiniranog molekula DMF (slika 1). Geometrija oko Cu(II)-atoma je kvadratno-piramidalna, čiju baznu ravan čine dva Oatoma i dva N-atoma iz dva L-liganda, dok apikalni položaj zauzima O-atom iz koordiniranog molekula DMF. Kristalno pakovanje uspostavljeno je prisustvom različitih nekovalentnih interakcija među diskretnim jedinkama kompleksa (C–H···O, π–π i slobodan elektronski par–π). Antioksidativna aktivnost polazne azo boje i kompleksa je određena pomoću ABTS (2,2’- azinobis(3-etilbenzotiazolin-6-sulfonat) testa. Kompleks je pokazao značajniju antioksidativnu aktivnost u odnosu na polaznu azo boju i askorbinsku kiselinu korišćenu kao standard. Kristalografski podaci: C70H74N18O14Cu2, Mr = 1518,55, trikliničan sistem, prostorna grupa P , a = 10,191(2), b = 13,012(3), c = 14,692(3) Å, α = 79,73(3), β = 71,96(3), γ = 80,20(3) °, V = 1808,9(7) Å3 , R1 = 0,0539 za 4663 refleksija sa I  2σ(I).

In recent years, heterocyclic azo dyes have played significant role in the development of the coordination chemistry, due to their wide application in the different fields of electrochemical and optical studies [1]. Moreover, metal complexes with heterocyclic ligands in their architecture have great biological potential since they exhibit cytotoxicity, antimicrobial and antioxidant activity [2]. In this work, pyridone azo dye (5-(4-methoxyphenylazo)-1-ethyl-3-cyano-6 hydroxy-4-methyl-2- pyridone, HL) is used for the complexation with Cu(II) ions in N,N-dimethylformamide (DMF) at room temperature. The obtained complex (CuL2(DMF)) is characterized by UV-Vis and ATRFTIR spectroscopy and single-crystal X-ray analysis. The asymmetric unit of complex is comprised of one Cu(II) atom, two chelate L ligands and one coordinated DMF molecule (Figure 1). The coordination geometry of Cu(II) atom is square-pyramidal with basal plane comprised of two O and two N atoms originating from L ligands while apical position is occupied by one O atom from coordinated DMF. The crystal packing is established with the presence of different noncovalent interactions between discrete complex units (C–H···O/N, π–π and lone pair–π). Furthermore, antioxidant activities of the starting azo dye and the complex have been evaluated by the ABTS (2,2’-azinobis-(3- ethylbenzothiazoline-6-sulfonate)) radicalscavenging assay. The complex exhibited more potent antioxidant activity than the starting dye and ascorbic acid used as standard. Crystal data: C70H74N18O14Cu2, Mr = 1518.55, triclinic, space group P , a = 10.191(2), b = 13.012(3), c = 14.692(3) Å, α = 79.73(3), β = 71.96(3), γ = 80.20(3) °, V = 1808.9(7) Å3 , R1 = 0.0539 for 4663 observed reflections with I  2σ(I).