One dense and two open chiral metal-organic frameworks: Crystal structures and physical properties

Three 3D robust homochiral helical coordination polymers, [Cu(2,2',3,3'-H(2)odpa)(bpy)] (1), {[Ni-4(2,2',3,3'-odpa)(2)-(bpy)(4)(H2O)(4)](.)(H2O)(16)} (2), and {[Co-4(2,2',3,3'-odpa)(2)(bpy)(4)(H2O)(4)](.)(H2O)(14)} (3), have been hydrothermally synthesized from a flexible ligand of 2,2',3,3'-odpda (2,2',3,3'-oxydiphthalic dianhydride). Compound 1 crystallized in space group P3(1)21 and has a rare chiral dense qzd 7.(5)9 topology that incorporates single helical substructures with the same accessibility, whereas compounds 2 and 3 crystallized in the space group C2 and possessed isostructural 3D chiral open frameworks based on the homochiral 2D sheets and 4,4'-bpy pillars. TGA and PXRD analyses show that the porous framework of 2 is stable after the removal of solvent water molecules. In contrast, 3 changed its structure to an amorphous one because of the simultaneous loss of solvent and coordination water molecules. I is nearly paramagnetic, whereas weak ferromagnetic interactions between M(II) (M = Ni, Cc) ions have been found in 2 and 3.