Synthesis, spectroscopy, and electrochemistry of copper(II) complexes with N, N′-bis(3,5-di- t-butylsalicylideneimine)polymethylenediamine ligands

• Published in: Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy Vol. 61; no. 1; pp. 225 - 231
• Main Authors: Kasumov, Veil T., Köksal, Fevzi
• Format: Journal Article
• Language: English
• Published: England Elsevier B.V 2005
• Subjects: Bulky polymethylene-salen Cu(II) complexes; Copper - chemistry; Electrochemistry; Electrons; Ligands; Magnetics; Molecular Structure; Organometallic Compounds - chemical synthesis; Organometallic Compounds - chemistry; Schiff Bases - chemical synthesis; Schiff Bases - chemistry; Spectroscopy; Spectrum Analysis; Electrochemistry; Spectroscopy; Bulky polymethylene-salen Cu(II) complexes
• ISSN: 1386-1425
• DOI: 10.1016/j.saa.2004.03.037

Bulky salen CuL x derived from aliphatic polymethylene diamines, H 2N(CH 2) x NH 2, where n=2–6, and 3,5-di- t-butylsalicylaldehyde (H 2L x ) and some corresponding tetrahydrosalan complexes (CuL x ′) have been synthesized and characterized by their IR, UV–vis absorption and EPR spectra, by magnetic moments and by cyclic voltammetry in acetonitrile (for H 2L x ) and DMF (for CuL x ). Complexes CuL x and CuL x ′ are magnetically normal ( μ exp=1.83–1.91 μ B). EPR spectra CuL x characterized by the axial g and A Cu tensors with g ||> g ⊥ and without 14N-shf resolution in CHCl 3/toluene at 300 and 150 K. The CV studies on acetonitrile solutions of H 2L x revealed a well-defined quasi-reversible redox wave at E 1/2=0.95–1.15 V versus Ag/AgCl but CV of the CuL x complexes in DMF exhibit weak pronounced irreversible oxidation waves at E pa 1=0.51−0.98 V and E pa 2=1.16−1.33 V attributable to metal centered Cu(II/III) and ligand centered CuL x /CuL x + couples, respectively. A poorly defined wave was observed for the quasi-reversible reduction Cu(II)/Cu(I) at potentials less than −1.0 V.