Synthesis, structure, spectra and solution behavior of the nickel(II) and copper(II) complexes of 3,7,10,14,15,19,20,24-octaazatricyclo[7.5.5.52,8]tetracosane (OCTC) Journal of the Indian Chemical Society, 2015
Nickel(II) and copper(II) complexes of some polycyclic aza ligands Journal of the Indian Chemical Society, 2013
Macrocyclic nickel(II) complexes of some polynucleating aza ligands Journal of the Indian Chemical Society, 2010
Studies on copper(II) complexes of some polyaza macrocycles derived from 1,2-diaminoethane Ankur Rastogi, Ram Nayan Journal of Coordination Chemistry, 2009 Syntheses of copper(II) complexes of 20-membered and 15-membered aza macrocycles 1,3,6,8,11,13,16,18-octaaza-2,7,12,17-tetrachlorocycloeicosane (OTCE, [20]-N8) and 1,3,6,8, 11,13-hexaazacyclopentadecane (HCPD, [15]-N6) involving metal template condensation between 1,2-diaminoethane, trichloromethane and dichloromethane, respectively, are reported. Formulation of [Cu4(OTCE)(H2O)8]Cl8 and [Cu3(HCPD)(H2O)6]Cl6 · 2H2O and the ligand hydrochlorides OTCE · 8HCl and HCPD · 6HCl are supported by elemental analyses, conductivity measurements, and spectral studies. For a comparative cavity size effect on the stability constant, potentiometric measurements on the copper complexes of the generated macrocycles [15]-N6 and [20]-N8 and the structurally related larger macrocycle 1,3,6,8,11,13,16,18,21,23-decaaza-2,2,7,7,12,12,17,17,22,22-decachlorocyclopentacosane (DDCP, [25]-N10, prepared recently) have been performed in aqueous solution at 25°C (μ = 0.1 M KNO3). Very high stability constants obtained for reaction Cu2+ + A ⇌ CuA2+ (A = ligand, log K = 20.51 and 25.87, respectively, for OTCE and DDCP systems) are a reflection on the folding of the ligand to provide a small cavity suitable for fitting of the copper ion. Further, a high equilibrium constant value for CuA2+ + Cu2+ ⇌ Cu2A4+ (OTCE system, log K = 14.59) or Cu2A4+ + Cu2+ ⇌ Cu3A6+ (DDCP system, log K = 16.69) is due to suitable fitting of two and three copper ions in the 20-membered and 25-membered ring cavity of OTCE and DDCP, respectively.
Synthesis, characterization and equilibrium studies of nickel(II) and copper(II) complexes of tetraaza macrocycles derived from dichloromethane Journal of the Indian Chemical Society, 2009
Macrocyclic nickel(II) and copper(II) complexes of the deca- and tetradecaaza ligands Journal of the Indian Chemical Society, 2008
