Synthesis and characterization of three novel manganese(II) octaaza macrocyclic Schiff base complexes containing a phenanthroline and two pyridyl units as pendant arms. X-ray crystal structure determination of one manganese(II) complex

摘要

Three new branched hexadentate amines (N-6), 3,6-bis(2-pyridylmethyl)-3,6-diazaoctane-1,8-diamine (1), 3,7-bis(2-pyridylmethyl)-3,7-diazanonane-1,9-diamine (2) and 3,8-bis(2-pyridylmethyl)-3,8-diazadecane-1,10-diamine (3) have been synthesized. Subsequently, three novel Schiff base macrocyclic complexes containing a phenanthroline and two 2-pyridylmethyl pendant arms have been prepared by template [1+1] cyclocondensation of 2,9-dicarboxaldehyde-1,10-phenanthroline and the branched hexadentate amines (1-3), in the presence of Mn(II) in methanol. These complexes have ligands with 18-, 19-and 20-membered hexaaza macrocycles and two 2-pyridylmethyl pendant arms (L-1, L-2 and L-3, respectively). All the complexes have been characterized by elemental analysis and IR spectroscopy. The crystal structure of [MnL1](ClO4)(2) center dot 3CH(3)CN was determined and indicates that in the solid state the complex adopts a slightly distorted hexagonal bipyramidal geometry with the Mn(II) ion located within a hexaaza macrocycle with the two 2-pyridylmethyl pendant arms coordinating in axial positions.