Triaquabis{2-methoxy-6-[(phenyliminiumyl)methyl]phenolate-κO 1}manganese(II) dinitrate

The crystal structure of the title compound, [Mn(C14H13NO2)2(H2O)3](NO3)2, is comprised of two Schiff base 2-methoxy-6-(N-phenylcarboximidoyl)phenol (HL) ligands and three coordinated water molecules. The MnII ion lies on a twofold axis that bisects one water O atom. The coordination sphere of the five-coordinate Mn atom is completed by the two monodentate HL ligands and three coordinated water molecules binding through their O atoms, affording a distorted tetragonal–pyramidal geometry. In the phenolate ligands, the hydroxy H atom transfers to the imine N atom. This H atom is also involved in an intramolecular N—H⋯O hydrogen bond that imposes a nearly planar conformation on each ligand, with dihedral angles of 2.78 (3) and 2.43 (5)° between the aromatic rings of each ligand. In the crystal, molecules are linked by intermolecular O—H⋯O hydrogen bonds.

The crystal structure of the title compound, [Mn(C 14 H 13 NO 2 ) 2 (H 2 O) 3 ](NO 3 ) 2 , is comprised of two Schiff base 2-methoxy-6-(N-phenylcarboximidoyl)phenol (HL) ligands and three coordinated water molecules. The Mn II ion lies on a twofold axis that bisects one water O atom. The coordination sphere of the five-coordinate Mn atom is completed by the two monodentate HL ligands and three coordinated water molecules binding through their O atoms, affording a distorted tetragonal-pyramidal geometry. In the phenolate ligands, the hydroxy H atom transfers to the imine N atom. This H atom is also involved in an intramolecular N-HÁ Á ÁO hydrogen bond that imposes a nearly planar conformation on each ligand, with dihedral angles of 2.78 (3) and 2.43 (5) between the aromatic rings of each ligand. In the crystal, molecules are linked by intermolecular O-HÁ Á ÁO hydrogen bonds.
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: RN2084).

Comment
It has well been documented that Schiff bases are important in diverse fields of chemistry and biochemistry owing to their biological activities (Garnovskii et al., 1993). The complexes prepared by ligands derived from o -vanillin have attracted considerable attention for a number of years due to the intriguing biological activities of o-vanillin and the convenience of the synthesis of related Schiff bases (Burrows & Bailar, 1966). For these reasons, we have been engaged in the syntheses of new Schiff bases derived from o-vanillin and their transition and rare earth metal complexes (Shen et al. 2011;Zhao et al. 2006). Herein, we describe a new Mn II complex.
The structure of complex (1) is shown in Fig. 1, which contains two 2-methoxy-6-(N-phenylcarboximidoyl)phenol (HL) ligands, three coordinated water molecules and two independent nitrate ions. The coordination sphere of the five-coordinate Mn atom is completed by the two monodentate HL ligands and three coordinated water molecules binding through their O atoms, affording a distorted tetragonal pyramid geometry. The coordination geometry around Mn II is better described as a The hydrogen bonds lend stability to the structure. The packing plot of this compound is shown in Fig. 2. In the phenolate ligands, the proton of the phenolic hydroxy group transfers to the imine N atom. This proton is also involved in an intramolecular N-H···O hydrogen bond that imposes a nearly planar conformation on each ligand, with dihedral angles of 2.78 (3) and 2.43 (5)° between the aromatic rings of each ligand. In the crystal structure, molecules are linked by intermolecular O-H···O hydrogen bonds.

Experimental
Reagents and solvents used were of commercially available quality. The Schiff base ligand 2-methoxy-6-(Nphenylcarboximidoyl)phenol was synthesized from condensation of o-vanillin and aniline. 1 mmol HLligand was dissolved in ethanol(20 ml), then 0.5 mmol Manganese nitrate solution (in ethanol). The mixture solution was stirred for 4 h at room temperature. The resulting solid was filtered out and the solution evaporated yielding red crystals of compound (1) after several days.

Refinement
The structure was solved by direct methods and successive Fourier difference synthesis. The H atoms bonded to C and N atoms were positioned geometrically and refined using a riding model [aliphatic C-H =0.96 Å (U iso (H) = 1.2U eq (C)), aromatic C-H = 0.93 Å (U iso (H) = 1.2 U eq (C)) and N-H = 0.86 Å with U iso (H) = 1.2U eq (N)]. Water H atoms bonded supplementary materials sup-2 to O atoms were located in difference Fourier maps and refined with O-H distance restraints of 0.83 (2)Å and U iso (H) = 1.5U eq (O). Fig. 1. The molecular structure of the title complex, showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 30% probability level. (The atoms labelled with the suffix A are related by the symmetry operation -x + 1,-y,-z + 1)