Synthesis, characterization and pseudopolymorphism of a phenoxo-bridged binuclear manganese(III) Schiff base complex

Three pseudopolymorphs of a phenoxo-bridged binuclear manganese(III) complex, [Mn(L)(N3)]2 where L = [N,N′-bis(2-hydroxyacetophenylidene)]propane-1,2-diamine could be synthesized using same reactants but different solvents. The syntheses of the unsolvated isomer [Mn(L)(N3)]2 (1) and a hydrated isomer [Mn(L)(N3)]2·3.66H2O (2) have been achieved in acetone and methanol medium, respectively, while another previously reported complex [Mn(L)(N3)]2·2C2H5OH (3) was obtained from a mixed solvent containing ethanol. The pseudopolymorphs 1, 2 and 3 crystallize in the space groups P21/c, P21/n and P21/n, respectively. Their 3D supramolecular structures have been compared to notice that the molecular building blocks are held by weak intermolecular C–H⋯π, C–H⋯O or van der Waals interactions. While the compound 1 is an unsolvated pseudopolymorph, 2 and 3 contain water and ethanol, respectively as guest molecules in their lattices.

Graphical abstractSyntheses, crystal and supramolecular structures of three pseudopolymorphs {[Mn(L)(N3)]2 (1), 1·water (2) and 1·ethanol (3) where L = [N,N′-bis(2-hydroxyacetophenylidene)]propane-1,2-diamine} comprising of the same phenoxo-bridged binuclear manganese(III) building block have been described.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Binuclear phenoxo-bridged manganese(III) Schiff base complexes have been prepared. ► The complexes exhibit pseudopolymorphism. ► Solvent molecules serve as templates to induce formation of the solvated complexes. ► Host–guest supramolecular interactions are operative in the solid state.