Preparation, crystal structure and solution studies of [Mn2L2Cl4(H2O)2], where L=2-(2′-pyridyl)quinoxaline

The reaction of MnCl2.4H(2)O with the biheteroaromatic ligand (L), formed the dinuclear complex bis[aquachloro-2-(2'-pyridyl)quinoxaline]di-mu-chloro dimanganese {[Mn2L2Cl4(H2O)(2)]}, which was studied in the solid state by thermal techniques [thermogravimetry (TG), differential thermogravimetry (DTG) and differential thermal analysis (DTA)], spectroscopy (IR, far-IR, electronic spectra), magnetic susceptibility, X-ray diffraction methods as well as in methanolic solution by electrospray mass spectrometry (ES-MS). The X-ray crystal structure showed two manganese(II) ions bridged by two chloro ligands with a terminal chloride, a water molecule and a chelating molecule of L, completing a six-coordinate octahedral geometry around each metal centre. The complex in methanolic solution decomposes, forming various monomeric species, as observed from both conductivity measurements and ES-MS. Anions of the general formula [(MnCl2)Cl](n)(-), where n=1, 2, 3, 4 and 5, were also observed in the negative ES mode. (C) 1999 Elsevier Science Ltd. All rights reserved.