New macrocyclic Schiff-base complexes incorporating a phenanthroline unit. Part 2: Template synthesis of some manganese(II) complexes and crystal structure studies

A series of Mn(II) macrocyclic Schiff-base complexes [MnLn](2) (+) have been prepared via the Mn( II) templated [1+1] cyclocondensation of 2,9-dicarboxaldehyde-1,10-phenanthroline with appropriate linear and branched amines. In this way ligands the pentaaza macrocycle L 1 which is 15-membered and L 2 which is 16-membered possessing no pendant arm, L 6 is 15-membered with one 2- aminoethyl pendant arm and L 8 which is 18-membered hexaaza macrocycle with two 2- aminoethyl pendant arms are formed. All the complexes have been characterized using spectroscopic methods. The crystal structures of [MnLn](ClO4)(2) center dot EtOH were determined and indicate that in the solid state the complex adopts a slightly distorted hexagonal bipyramid geometry with the Mn( II) ion located within a hexaaza macrocycle with the two pendant amines coordinating in the axial positions. (c) 2007 Elsevier B. V. All rights reserved.