Syntheses, crystal structures and properties of new manganese(II) complexes with macrocyclic polyamine ligands bearing pyridyl donor pendants

Two new Mn-II complexes with polydentate macrocyclic polyamine ligands func tionalized with pyridyl donor pendants, 1,4,7,10-tetrakis(2-pyridylmethyl)- 1,4,7,10-tetraazacyclododecane (L-1) and 1-methly-4,7,10-tris(2-pyridylmeth yl)-1,4,7, 10-tetraazacyclododecane (L-2), have been synthesized and their structures determined by X-ray diffraction analysis. In [MnL1](ClO4)(2) (I) , the Mn-II central ion is eight-coordinated with all the eight donor nitro gens of L-1 (including four pendant pyridyl nitrogens and four tertiary ami nes of cyclen) to form a distorted square-prism coordination geometry, and in [MnL2](ClO4)(2) (II), the M-II central ion is seven-coordinated (distort ed monocapped octahedral geometry) with all the seven nitrogen donor atoms of L2 (including three pendant pyridyl nitrogens and four tertiary amines o f cyclen) comprising the donor set. The solution chemistry of the two Mn-II complexes has been further studied by cyclic voltammetry (CV), W-Vis and E SR spectral techniques. (C) 2000 Elsevier Science Ltd. All rights reserved.