New pyridine-monoacylhydrazidate-coordinated transition-metal complexes

By applying the hydrothermal in situ acylation reactions between alkyl-substituted pyridine-2,3-dicarboxylic acids and hydrazine hydrate, six pyridine-monoacylhydrazidate-coordinated transition-metal complexes [Mn(MPDH)2] 1, [M(MPDH)2(H2O)2]·2H2O (M2+ = Co2+2, Zn2+3), [Mn(EPDH)2(H2O)2] 4 and [M(EPDH)2(H2O)2] (M2+ = Zn2+5, Co2+6) (MPDH = 6-methylpyridine-2,3-dicarboxylhydrazidate; EPDH = 5-ethylpyridine-2,3-dicarboxylhydrazidate) were obtained. Although only compound 1 is a 1-D chained coordination polymer and the others are the mononuclear molecular entities, they all further self-assemble into the interesting supramolecular networks via hydrogen-bonded interactions between pyridine-monoacylhydrazidate ligands. Two Zn2+ compounds 3 and 5 possess the fluorescence properties with maximum emissions at 517 nm for 3 and 530 nm for 5 upon excitation, respectively. The magnetic analysis for compound 1 indicates there exists the antiferromagnetic interactions between the Mn(II) ions.

By applying the hydrothermal in situ acylation reactions between alkyl-substituted pyridine-2,3-dicarboxylic acids and hydrazine hydrate, six pyridine-monoacylhydrazidate-coordinated transition-metal complexes were luckily obtained.Figure optionsDownload as PowerPoint slideHighlights
► Six acylhydrazidate-coordinated complexes were hydrothermally synthesized.
► Acylhydrazidate was from in situ acylation of polycarboxylic acid with N2H4.
► Character for pyridine-acylhydrazidate has been preliminarily understood.
► Substituted alkyl groups have the effect on the network for obtained complexes.