Crystal structure of six and seven coordinate manganese(II) complexes with penta and hexadentate pyridylmethyl ligands

• Published in: Inorganica Chimica Acta 2005-09, Vol.358 (13), p.3873-3880
• Main Authors: Ghachtouli, Sanae El, Mohamadou, Aminou, Barbier, Jean-Pierre
• Format: Article
• Language: English
• Subjects: Chemical Sciences; Coordination chemistry; Crystal structure; Hexadentate ligand; Pentadentate ligand; Seven-coordinate manganese(II) complex; Six-coordinate manganese(II) complex
• ISSN: 0020-1693; 0073-8085; 1873-3255
• DOI: 10.1016/j.ica.2005.06.050

The reaction of manganese(II) ion with linear pentadentate or hexadentate pyridylmethyl ligands in the presence of chloride or thiocyanate ions gives six- and seven-coordinate manganese(II) complexes. Two six-coordinated manganese(II) complexes [Mn(pydien)Cl](ClO 4) · C 2H 5OH ( 1), [Mn(pydien)NCS](ClO 4) ( 2) and two seven-coordinated manganese(II) complexes [Mn(pydado)Cl](ClO 4) ( 3), [Mn(pydado)NCS](ClO 4) ( 4) have been obtained using linear penta and hexadentate ligands pydien and pydado (pydien: 1,7-bis(2-pyridylmethyl)-1,4,7-triazaheptane and pydado: 1,10-bis(pyridylmethyl)-1,10-diaza-4,7-dioxadecane). The crystal structures for all compounds have been determined. 1 and 3 crystallize in the triclinic space group P 1 ¯ , 2 crystallizes in the orthorhombic space group Pbca, whereas 4 crystallizes in the monoclinic space group P2 1/ c. The bound anion (chloro or isothiocyanato) in complexes 1 and 2 has no influence on the geometry of six-coordinate manganese(II) complexes, whereas the geometry and the wrapping of the hexadentate ligand (pydado) around Mn 2+ cation depend on the nature of the bound anion. The complex 3 has a capped octahedron geometry with the two pyridyl groups in trans position, while the geometry of complex 4 can be described as pentagonal bipyramid with one pyridyl group and a thiocyanate anion in the axial positions.