KRISTALNA STRUKTURA, SPEKTRALNA I TERMALNA SVOJSTVA Cu(II)-KOMPLEKSA AZO PIRIDONSKE BOJE

Abstract

Heterociklične azo boje koje u svojoj strukturi imaju piridonsko jezgro pokazale su se kao efikasni helatni ligandi pri formiranju bakаr(II)-kompleksa [1]. Kompleksi azo piridonskih boja primenjuju se u optičkim slojevima za snimanje i karakterišu se dobrom stabilnošću na uticaj svetlosti i povišene temperature [2]. Azo-hidrazon tautomerija predstavlja značajan fenomen pri kompleksiranju ovih boja sa jonima prelaznih metala, zbog transformacije hidrazonskog mosta u bojama u azo-vezu u kompleksu. Reakcijom 5-(4-hlorfenilazo)-1-etil-3- cijanо-6-hidroksi-4-metil-2-piridona (HL) i Cu(CH3COO)2ꞏH2O rastvorenog u N,N-dimetilformamidu (DMF) na sobnoj temperaturi, sintetisan je kompleks [CuL2(DMF)]ꞏDMF. Kompleks je okarakterisan UV-Vis i ATR-FTIR spektroskopijom, simultanom TG/DSC- i rendgenskom strukturnom analizom. Asimetričnu jedinicu kompleksa čine Cu(II)-atom, dva helatna L-liganda, jedan koordiniran i jedan nekoordiniran molekul DMF (slika 1). Kvadratnopiramidalno okruženje Cu(II)-atoma čine dva O-atoma i dva N-atoma iz dva molekula L-liganda i O-atom iz koordiniranog molekula DMF. Stabilizacija kristalne strukture postignuta je slabim nekovalentnim interakcijama: C–HꞏꞏꞏO/N, π–π, C–Hꞏꞏꞏπ, slobodan elektronski par–π i ClꞏꞏꞏCl. Kristalografski podaci: C36H38N10O6Cl2Cu, Mr = 841,20, trikliničan sistem, prostorna grupa P , a = 10,109(5), b = 11,753(6), c = 17,447(8) Å, α = 74,152(4), β = 85,600(4), γ = 77,357(4) °, V = 1945,41(17) Å3 , R1 = 0,059 za 5929 refleksija sa I  2σ(I).

Heterocyclic azo dyes bearing pyridone ring as a coupling constituent are recognized as efficient chelating agents for copper(II) [1]. Complexes of azo pyridone dyes find application in optical recording layers with improved light stability and are characterized by good thermal and light stability [2]. Azo-hydrazone tautomerism of these dyes is evidenced as the significant phenomenon in their coordination since hydrazone bridge in dyes transforms to azo bond upon complexation. In the reaction of 5-(4-chlorophenylazo)-1-ethyl-3-cyano6-hydroxy-4-methyl-2-pyridone (HL) with Cu(CH3COO)2ꞏH2O in N,Ndimethylformamide (DMF) at room temperature, a complex [CuL2(DMF)]ꞏDMF has been prepared. The complex is characterized by UV-Vis and ATR-FTIR spectroscopy, simultaneous TG/DSC and single-crystal X-ray analysis. The asymmetric unit of the complex is comprised of one Cu(II) atom, two chelate L ligands, one coordinated and one noncoordinated DMF molecule (Figure 1). Cu(II) atom is surrounded by two O and two N atoms from two L ligands and by one O atom from coordinated DMF, forming a square pyramidal environment. The stabilization of the crystal packing is achieved by weak non-covalent interactions: C–HꞏꞏꞏO/N, π–π, C–Hꞏꞏꞏπ, lone pair–π and ClꞏꞏꞏCl. Crystal data: C36H38N10O6Cl2Cu, Mr = 841.20, triclinic, space group P , a = 10.109(5), b = 11.753(6), c = 17.447(8) Å, α = 74.152(4), β = 85.600(4), γ = 77.357(4) °, V = 1945.41(17) Å3 , R1 = 0.059 for 5929 observed reflections with I  2σ(I).