Copper(II) complex with L-arginine – Crystal structure, DFT calculations, spectroscopic, thermal and magnetic properties

• Published in: Materials chemistry and physics Vol. 228; pp. 272 - 284
• Main Authors: Wojciechowska, Agnieszka, Janczak, Jan, Zierkiewicz, Wiktor, Rytlewski, Piotr, Rojek, Tomasz, Duczmal, Marek
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15-04-2019
• Subjects: Copper(II); DSC; EPR; FT−IR; L−arginine; Magnetic properties on Exchange coupling through N–H; NIR−Vis−UV; Structure; NIR−Vis−UV; DSC; EPR; L−arginine; Structure; FT−IR; Copper(II); Magnetic properties on Exchange coupling through N–H
• ISSN: 0254-0584; 1879-3312
• DOI: 10.1016/j.matchemphys.2019.02.037

Complex of formula [Cu(L−Arg)(phen)Cl]Cl·2H2O (1) was synthesized in crystalline form (triclinic crystal system, P1 (No. 1) space group with a = 9.376(1) Å, b = 10.415(1) Å, c = 12.209(2) Å and Z = 2). The relations between the crystal structure, DFT calculations, spectroscopic properties (FT−IR, FT−Raman, NIR−Vis−UV, EPR) as well as the parameters of magnetic data were investigated. The square pyramidal geometry around copper (II) cations is very slightly distorted toward bipyramid geometry. The DFT-calculated interaction energies (ΔE) for the L−Arg zwitterion and phen ligands are −135.31 and −54.17 kcal mol−1, respectively. The g tensor diagonal components obey the relationship g|| > g⊥ (g⊥ = 2.063, g|| = 2.23) which suggested the pure dx2-y2 ground state orbital. Analysis of the crystal structure shows two possible magnetic exchange pathways: the neighboring [Cu(l−Arg)(phen)Cl]+ cations are linked in dimeric units by the N−H⋯Cl type hydrogen bonds, and almost parallel phenanthroline molecules provide π–π stacking interaction between the dimers. Analysis of the magnetic data, using an alternating ferro− and antiferromagnetic chain model for S = 1/2 spins, reveals the existence of weak antiferromagnetic coupling within the dimers (JAF = −0.23 cm−1) and weak ferromagnetic interaction between dimers (JF = 0.11 cm−1).
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•Cu(II) complex of L−Arginine was synthesized in crystalline form and characterized.•The interaction energies (ΔE) for ligands were calculated.•Two possible magnetic exchange pathways provide π–π stacking interaction.