Three Co(II) metal-organic frameworks based on a substituted thiophene carboxylic acid ligand with semiconductive properties

Three Co(II) metal-organic frameworks, based on a thiophene-containing ligand have been hydrothermally synthesized. Due to the rotation of the C-C single bonds between thiophene and benzene rings, MOFs 1-3 exhibit fantastic and different topological structures. 1 possesses a 1D double chains structure. 2 shows a novel 2D + 2D→ 2D network with unusual polyrotaxane entanglements of (4, 4)-sql subnets. 3 displays a non-interpenetrated 2D sheet with the point symbol {44.62} sql net topology. All the structures can further extend via O-H···O hydrogen bonds, C-H···π or π···π interactions into 3D supramolecular frameworks. In addition, solid-state UV-vis spectra experiments show that 1-3 exhibit semiconductive properties.253