Preparation and structures of trinuclear manganese(II) complexes with N-2-pyridiylmethylidene-2-hydroxy-5-substituted-phenylamine
Introduction
The chemistry of manganese complexes is of interest as models for biological redox systems involving manganese ions, such as the oxygen-evolving center (OEC) of Photosystem II in green plants, superoxide dismutases (SOD) and Mn-catalases (CAT). In the past two decades, polynuclear manganese complexes have been extensively prepared and characterized as structural and functional models for the above manganese-containing systems [1], [2], [3], [4], [5], [6].
Linear trinuclear manganese complexes bridged by acetato anions have been recently reported [7], [8], [9], [10], [11], [12], [13]. In this paper, we describe the preparation and structures of trinuclear manganese(II) complexes obtained by the reactions of MnII(OAc)2·2H2O and tridentate Schiff base ligands papH and 5-Cl-papH (see Fig. 1), where papH and 5-Cl-papH denote [N-2-pyridiylmethylidene-2-hydroxy-phenylamine] and [N-2-pyridiylmethylidene-2-hydroxy-5-chloro-phenylamine], which were derived from pyridine-2-aldehyde and 2-amino-phenol and 2-amino-4-chloro-phenol, respectively.
Section snippets
Preparation of trinuclear manganese(II) complexes
The trinuclear manganese(II) complex, [MnII3(OAc)4(pap)2(H2O)2] (1) was prepared by the reaction of papH (0.298 g, 1 mmol) and MnII(OAc)2·2H2O (0.276 g, 1.5 mmol) in methanol (MeOH, 400 ml) with stirring at room temperature for 30 min. The resulting red solution was allowed to stand in the dark. After 12 h, the resulting red crystals were collected on a glass filter, and dried in vacuo. The yield was 75.6%. [MnII3(OAc)4(5-Cl-pap)2(MeOH)2] (2) was obtained by the same manner in 68.0% yield.
Structure of trinuclear manganese(II) complexes
Fig. 2, Fig. 3 show the molecular structures of trinuclear manganese(II) complexes [MnII3(OAc)4(pap)2(H2O)2] (1) and [MnII3(OAc)4(5-Cl-pap)2(MeOH)2] (2), respectively. For both trinuclear manganese(II) complexes, two terminal manganese ions are coordinated with one oxygen and two nitrogen atoms of pap, two oxygen atoms of OAc− and one oxygen atom of water for 1 and MeOH for 2, respectively, to form a distorted octahedral structure. The central manganese ion resides on a center of symmetry and
Supplementary data
Supplementary data are available from the CCDC, 12 Union Road, Cambridge CB2 1EZ, UK, deposition numbers 189983 and 189984 for complexes 1 and 2, respectively.
Acknowledgements
This work was partially supported by a grant based on High-Tech Research Center Program for private Universities from the Japan Ministry of Education, Culture, Sports, Science and Technology.
References (16)
- et al.
Polyhedron
(1994) - et al.
Adv. Inorg. Chem.
(1999) Manganese Redox Enzymes
(1992)- et al.
Chem. Rev.
(1994) - et al.
Chem. Rev.
(1996) - et al.
Chem. Rev.
(1997) - et al.
Coord. Chem. Rev.
(1995) - et al.
Angew. Chem. Int. Ed. Engl.
(1990)
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