Two new supramolecular architectures of singly phenoxo-bridged copper(II) and doubly phenoxo-bridged manganese(II) complexes derived from an unusual ONOO donor hydrazone ligand: syntheses, structural variations, cryomagnetic, DFT, and EPR studies
Résumé
Two new coordination complexes {[(L)Cu2('-L)(NO3)(CH3OH)0.3(H2O)0.7]·NO3}[Cu(L)(NO3)(CH3OH)] (1) and [Mn2(-L)2(H2O)(1-N3)2(CH3OH)] (2) derived from (E)-N-(2-hydroxy-3-methoxybenzylidene)acetohydrazide [LH] have been synthesized. The new potentially tetradentate ONOO donor hydrazone ligand [LH] has shown considerable metal ion selective phenoxo bridging in 1 and 2. It has coordinated copper(II) ions in its tridentate as well as in tetradentate fashion whereas for manganese(II) ions it solely showed its tetradentate character. In 1 the two adjacent pentacoordinate copper(II) centers are connected by a rare single phenoxo linkage of the hydrazone ligand whereas 2 is a doubly phenoxo-bridged heptacoordinated manganese(II) dinuclear species. The 3D supramolecular networks of 1 and 2 have resulted from extensive H-bonding interactions in the respective complexes. Structural variations observed for 1 and 2 have been described by performing single-crystal X-ray analysis. The ligand and the complexes are characterized by elemental analyses, IR, UV/Vis and 1H NMR spectroscopy. Cryomagnetic investigations, DFT studies and EPR analysis, of 1 and 2 have also been studied in detail.