New synthesis and structure of a polar manganese coordination polymer

Abstract

A new synthesis of [N,N′-ethylenebis(salicylaldiminiato)((4-pyridylthio)acetate)] manganese(III) (Mn(Salen) polymer) has been developed, and the structure of a methanol adduct of the compound has been determined at 293 K. The compound crystallizes as an infinite chain polymer, where the Mn metal center is bridged by the (4-pyridylthio)acetate ligand. The Mn center is octahedrally coordinated with the equatorial positions being occupied by the Salen ligand. The axial positions are occupied by a pyridyl nitrogen and a carboxylate oxygen. The iteration of this bonding pattern gives the polymer a head-to-tail backbone. The major structural difference between this compound and the one previously reported occurs on the nonmetalated oxygen of the carboxylate functionality (W. Chaing, D.M. Ho, D. Van Engen, M.E. Thompson, Inorg. Chem. 1993, 32, 2886; W. Chaing, Doctoral Thesis, Princeton University, Princeton, 1994). In the original structure, H₂O is hydrogen bonded to the nonmetalated oxygen; however, in the structure reported here methanol is intercalated between chains without any hydrogen bonding. This indicates that this polymer can be viewed as host–guest system and that solvent plays no role in the formation of the structure.