Conformational isomerism of a flexible fluorinated bis-pyridinecarboxamide ligand in the structural direction of two distinct layered CuII coordination polymers

Reaction of a flexible pyridinecarboxamide ligand N,N′-[(2,3,5,6-tetrafluoro-1,4-phenylene) bis(methylene)]bis(pyridine-4-carboxamide) (H2tfpbbp) with CuII chloride or perchlorate affords two coordination polymers {[Cu(H2tfpbbp)(tfpbbp)(H2O)] · 2DMF · 4H2O}n (1) and {[Cu(H2tfpbbp)2(ClO4)2] · 3H2O}n (2). Both complexes have 2-D (4,4) layered networks extended by the exo-bidentate bridging ligands, which however consist of distinct [Cu–ligand]4 meshes owing to the conformational difference of ligands. Their spectroscopic, thermal, and fluorescence properties have also been investigated.