Crystal Structure of Diaqua[N,N′-bis(3-methoxysalicylidene)propane-1,2-diaminato]manganese(III) nitrate monohydrate

Hulya KARA
2008 Analytical Sciences X-ray Structure Analysis Online  
Much recent interest in the coordination chemistry of manganese with N and/or O containing ligands has been driven by the important roles in metalloenzymes and highly valuable catalysts in olefin expoxitation, 1 optical and magnetic materials. 2,3 In particular, manganese derivatives from tetradentate Schiff-base ligands have a clear tendency to form infinite linear or helical chains, due to the predisposition of these ligands to occupy a planar configuration in octahedral coordination
more » ... leaving the axial positions free to develop polymerization through bidentate bridges. 4 Recently, part of our research program has focused on Schiff-base Mn III complexes. 2,3 As an extension of the research on the structural characterization of Mn III complexes, here the crystal structure of the title compound, which is a hydrogen-bonded linear chain of pseudodimers Schiff-base Mn III complex having elongated axial Mn-O bonds to two aqua ligands, is reported. The ligand was prepared by the reaction of 1,2diaminopropane (1 mmol) with 3-methoxysalicylaldehyde (2 mmol) in hot ethanol (100 mL). A yellow compound was precipitated from the solution upon cooling. The title compound was prepared by the addition of manganese(III) nitrate dihydrate (1 mmol) in 70 mL of hot ethanol to the ligand (1 mmol) in 100 mL of hot methanol. The resulting solution was stirred for 10 min. A deep-green solution was obtained, which was allowed to stand at room temperature. Several weeks of standing led to the growth of deep-green crystals of the title compound, suitable for X-ray analysis. Anal. Calcd for C19H25MnN3O10: C, 44.71; H, 4.94; N, 8.23%. Found: C, 44.50; H, 5.02; N, 8.35%. Diffraction measurements were made on three-circle CCD diffractometers using graphite-monochromated Mo-Ka radiation at 100 K. The intensity data were integrated using the SAINT program. The structure was solved by direct methods, and refined using full-matrix least squares against F 2 using SHELXTL. All non-hydrogen atoms were refined anisotropically. The 1,2-diaminopropane portion of the ligand is disordered over two positions, which manifests itself as a terminal methyl group (atoms C19A or C19B) being attached to either C17 or C18, with 67% and 33% occupancy, respectively. The water molecule O10 is disordered over two positions (O10a/ O10b) with occupancies of 0.4/0.6. The positions of the water H atoms were located from difference Fourier maps. The O-H distances were restrained to 0.80(2)Å, with Uiso(H) = 1.5Ueq(O). In complex (I), the molecule comprises a manganese(III) centre coordinated by the nearly planar Schiff-base ligand [the X-ray Structure Analysis Online The title compound, a hydrogen-bonded linear chain of pseudodimers, Mn(C19H19N2O4)(H2O)2]NO3·H2O, (I), has been determined. The complex affords an elongated octahedral MnN2O4 coordination environment, geometry with the four donor atoms of the tetradentate Schiff base in the equatorial plane and with two aqua ligands in axial positions with Mn-O = 2.238(4) and 2.256(3)Å.
doi:10.2116/analscix.24.x263 fatcat:hhhc5szs2ffs3ays4rr5vvkvnu