名称:
XRD structure of two heptacoordinated Mn(II) complexes containing 2,9-dimethyl-1,10-phenanthroline (phen), nitrato and nicotinato bidentate anions: [Mn(phen)(nicot)(NO3)(H2O)]·EtOH·H2O and [Mn(phen)(NO3)2(H2O)]
摘要:
The XRD structure of two seven-coordinated Mn(II) complexes with the formula [Mn(phen)(nicot)(NO3) (H2O)]center dot EtOH center dot H2O Wand [Mn(phen)(NO3)(2)(H2O)] (2) are reported. The 2,9-dimethy1-1,10-phenanthroline, nitrato and nicotinato anions act as bidentate ligands, with Mn-N distances of 2.21-2.29 angstrom and Mn-O distances of 2.17-2.40 angstrom. In both compounds, the water molecule seems to be the strongest coordinated ligand, with bond distances of 2.139(2) angstrom in 1 and 2.195(2) angstrom in 2. The average ratio between coordinated unidentate and bidentate bond lengths less than the unity justifies, from an energetical point of view, the shape of the coordination polyhedra. In the structure of 1, the coordination polyhedron may be best-described as a distorted pentagonal bipyramid with a nitrogen from phenanthroline and the water molecule occupying the apical sites. The polyhedron shape for 2 is close to a square-capped trigonal prism, the capping site being occupied by the water molecule. The crystal structures are built by H-bonded bidimensional sheets piled up by it-it stacking of the partially interpenetrated aromatic moieties of adjacent layers. (C) 2010 Elsevier Ltd. All rights reserved.