Structural and mechanistic studies of co-ordination compounds. Part XII. Syntheses and characterization of some dianiono(1,4,8,11-tetra-azacyclotetradecane)-manganese(III), -iron(III), and -nickel(III) salts
作者:Pui-Ki Chan、Chung-Kwong Poon
DOI:10.1039/dt9760000858
日期:——
r. spectra in the 790–910 cm–1 region. In some cases, the assignment of a trans configuration to the dihalogeno-complexes is confirmed by the presence of only one ν(M–X) stretching frequency in their far-i.r. spectra. Magnetic susceptibilities show that all the d4 complexes prepared are high spin, whereas d6 and d7 complexes are low spin. For the d5 iron(III) system, all the cis complexes prepared are
The syntheses, structures and magnetic properties of five new manganese (III) cyclam complexes, trans-[Mn(cyclam)(OH2)(2)]-(CF3SO3)(3)center dot-H2O, trans-[Mn(cyclam)I-2]I, trans-[Mn(cyclam)(ONO)(2)]ClO4, trans-[Mn(cyclam)(OClO3)(2)]ClO4 and trans-[Mn(cyclam) (CH3COO)(CH3COOH)](ClO4)(2), are reported. Cyclam is the tetradentate amine ligand 1,4,8,11-tetraazacyclotetradecane. The complexes all exhibit pronounced tetragonal elongation of the coordination octahedron with the four cyclam nitrogens occupying the four equatorial positions. The magnetic properties are consistent with the formulation of the complexes as high-spin d(4) systems. trans-[Mn(cyclam)(OH2)(2)](CF3SO3)(3)center dot H2O is shown to be a convenient starting material for the syntheses of trans cyclam complexes. [Mn(cyclam)(CH3COO)(CH3COOH)](ClO4)(2) exhibits extremely short intermolecular hydrogen bonds resulting in a pseudo-chain structure. The tilt of the axial ligands with respect to the equatorial plane containing the manganese and the cyclam nitrogen atoms is discussed. (c) 2004 Elsevier B.V. All rights reserved.