Hydrothermal Syntheses, Crystal Structures, and Properties of a Novel Class of 3,3‘,4,4‘-Benzophenone-tetracarboxylate (BPTC) Polymers

Three novel BPTC complexes, (H2BPTC)(4,4‘-H2bpy)H2O (1), [Cd2Cu(HBPTC)2(μ2-4,4‘-bpy)2(4,4‘-bpy)2(H2O)2]n (2),
and [Co3(HBPTC)2(μ2-4,4‘-bpy)3(H2O)4]n·2nH2O (3) (BPTC = 3,3‘,4,4‘-benzophenone-tetracarboxylate and bpy =
bipyridine), were hydrothermally synthesized. Complex 1, which is obtained as a coproduct during the syntheses
of complexes 2 and 3, features a 2-D layered strong hydrogen bonding network with 2-fold interpenetration. Complex
2 has an unusual 2-D double-layered motif, which is linked together by Cu atoms in a face-to-face manner. It
exhibits nanosized channels filled by 4,4‘-bpy ligands. Three six-coordinated Co atoms in 3 are interlinked by
HBPTC ligands to form a 2-D grid structure, which is further sustained by rigid 4,4‘-bpy ligands into a 3-D open
framework similar to CdSO4 with the BPTC moieties situated in the tunnels. The thermal stabilities of complexes
1−3 were examined. The photoluminescence properties of complexes 1−2 and temperature-dependent magnetic
susceptibility for 3 were also studied.