From the hydrothermal in situ amidation reactions of aromatic polycarboxylates and hydrazine hydrate (N2H4·H2O), four complexes, dinuclear [Cu(μ2-H3bbch)(H2O)]2·2H2O (1), 3-D grid-like [Fe3(μ5-Hbbch)2(μ2-H2O)2(H2O)2]·2H2O (2), 2-D layer [Zn(μ2-H2bbh)(μ2-N2H4)1/2(H2O)]·2H2O (3) and 3-D supramolecular structure [Cd(H2bch)2(2,2′-bpy)(H2O)2][Cd(μ2-H2bch)(2,2′-bpy)(H2O)2](H2bch) (4) have been prepared. The two different in situ amidated ligands in 1, 2 and 3, benzene-4,5-bicarboxylate-1,2-hydrazide (H4bbch) and benzene-1,2,4,5-bihydrazide (H4bbh), were formed through adjusting the ratios of pyromellitic acid (PMA) and N2H4·H2O, of which H4bbch was generated through hydrothermal in situ amidation reactions for the first time. Benzene-4-carboxylate-1,2-hydrazide (H3bch), displaying three new coordination modes in 4, was also an in situ amidation product of benzene-1,2,4-tricarboxylic acid (H3btca) and N2H4·H2O. 1–4 were characterized by elemental analysis, infrared spectroscopy, and thermogravimetric analysis. Their structures were determined by single-crystal X-ray diffraction. The fluorescence properties of compounds 1, 3 and 4 were also investigated.
