Solid-State Arrangement and Magnetic Properties of Hybrid Copper(II)-L-Arginine 1D Coordination Polymer Based on Nitrate Bridges.

Copper-(II) coordination compounds are prospective building blocks of magnetic materials for future technologies and biologically active compounds. Their magnetic properties are greatly influenced by coordinating ligands, counterions, cocrystallization partners, and crystal arrangements. The self-organization of crystal structures containing [Cu-(Arg)-(B)]2+ cationic complexes is largely determined by the type of counteranions. Using NO3 - ions resulted in the formation of a new copper-(II) l-arginato 1D polymeric complex, with the following formula: {[Cu-(l-Arg)-(phen)-(μ-NO3)]-(NO3)·H2O}n. The results demonstrate the importance of interactions between NO3 - and the [Cu-(l-Arg)-(phen)]2+ coordination units in constructing the unit cell, stabilizing the structure and the spectroscopic and magnetic properties. The [Cu-(l-Arg)-(phen)]2+ cations are linked by NO3 - axial-axial bridges with Cu···Cu distance of 7.071 Å, which induced weak antiferromagnetic interactions between copper-(II) ions with S = 1/2. The O···H intermolecular interactions mostly control the molecular packing. The EPR (g ⊥ = 2.056, g || = 2.230) and vis (16970 cm-1) parameters confirm the elongated octahedral geometry (T = 0.76) and SOMO oriented in the xy plane N3O coordination sphere. Solid-state 13C NMR spectroscopy is used to characterize the distribution of spin density in organic ligands, with relativistic two-component (SO-ZORA) DFT calculations used to interpret experimental 13C NMR data. Our current N3O coordination polymer belongs to an interesting class of weakly coupled antiferromagnetic compounds.