A New Route for Preparing Coordination Polymers from Hydrothermal Reactions Involving in Situ Ligand Synthesis

The coordination chemistry of inorganic cobalt salt and the organic ligands H4bbh (=benzene-1,2,4,5-bihydrazide)
and H3bcbh (=benzene-4-carboxylate-1,2-bihydrazide) generated through the in situ hydrothermal acylate reaction
of H4bta (=benzene-1,2,4,5-tetracarboxylic acid) and H3btc (=benzene-1,2,4-tricarboxylic acid) with hydrazine hydrate,
respectively, has been investigated. Three new coordination polymers were prepared and fully characterized by
infrared spectroscopy, elemental analysis, and single-crystal X-ray diffraction. The compound [Co(μ3-H2bbh)(phen)]n
(1) (triclinic space group P1̄ with a = 9.762(4) Å, b = 10.169(4) Å, c = 11.143(4) Å, α = 80.96(3)°, β =
64.49(3)°, γ = 71.88(3)°, Z = 2) was synthesized from the reaction of CoCl2·6H2O, H4bta (=benzene-1,2,4,5-tetracarboxylic acid), N2H4·H2O, phen (=1,10-phenanthroline) and H2O, and consists of one-dimensional double-chains. [Co(μ4-H2bbh)(H2O)2]n (2) (monoclinic space group P2(1)/c with a = 6.8687(5) Å, b = 7.5943(6) Å, c =
10.0401(6) Å, β = 95.250(4)°, Z = 2) was generated by the combination of CoCl2·6H2O, H4bta, N2H4·H2O, and
H2O. It adopts a three-dimensional structural motif in the solid state with channels consisting of 20-numbered rings.
[Co(μ3-Hbcbh)(bpy)]n (3) (monoclinic space group Cc with a = 9.9464(13) Å, b = 23.685(5) Å, c = 7.9491 (16)
Å, β = 117.677(13)°, Z = 4) was obtained from the mixture of CoCl2·6H2O, N2H4·H2O, H3btc (=benzene-1,2,4-tricarboxylic acid), bpy (=2,2‘-dipyridyl), and H2O, and features a two-dimensional plane. The results of magnetic
research indicate that there exist antiferromagnetic interactions between Co centers in both compounds 1 and 2.