Synthesis and properties of (2-pyridyl)alkylamine- and (2-pyridyl)alkylamine-amide-coordinated copper(II) complexes: Structures and non-covalent interactions

摘要

Reaction of the ligand N-methyl-N-((6-pivaloylamido-2-pyridyl)methyl)-N-(2-pyridylethyl)amine (mpppa) with equimolar amounts of [Cu(H2O)(6)][ClO4](2) or CuCl2 center dot 2H(2)O in MeCN afforded mononuclear copper(II) complexes [Cu(mpppa)][ClO4](2) (1) and [Cu(mpppa)Cl-2] (2). Crystal structure analysis reveals CuN3O (two pyridyl, an aliphatic amine, and an amide oxygen) coordination in 1 and CuN3Cl2 (two pyridyl, an aliphatic amine, and two chlorides) coordination in 2. Crystal packing diagram of 1 reveals that one of the perchlorate counteranions provides weak coordination to copper(II) centers and in turn the copper(II) centers assume pseudo-six-coordination, generating 1D chain. Notably, one of the copper(II)-coordinated chloride ions in 2 participates in an intramolecular N-H center dot center dot center dot Cl interaction. Intermolecular C-H center dot center dot center dot Cl interactions in the solid state generate helical structure. Spectroscopic (IR, UV-Vis, and EPR) and redox properties of the two complexes have been investigated and compared.