A two-fold interpenetrated flexible bi-pillared-layer framework of Fe(II) with interesting solvent adsorption property

A two-fold interpenetrated microporous bi-pillared-layer framework of Fe(II), {[Fe(2,6-napdc)(4,4'-bipy)](EtOH)(H2O)}(n) (1) (2,6-napdc = 2,6-naphthalenedicarboxylate; 4,4'-bipy = 4,4'-bipyridine) composed of mixed ligand system has been synthesized and structurally characterized. The 2,6-napdc linkers form a 2D corrugated sheet of {Fe(2,6-napdc)}(n) by linking the secondary building unit of Fe-2(CO2)(2) in the ac plane, which are further connected by double 4,4'-bipy pillars resulting in a bi-pillared-layer type 3D framework. The 3D framework is two-fold interpenetrated and exhibits a 3D channel structure (4.0 x 3.5, 1.5 x 0.5 and 2.2 x 2.1 angstrom(2)) occupied by the guest water and ethanol molecules. Framework 1 shows high thermal stability, and the desolvated framework (1') renders permanent porosity realized by N-2 adsorption profile at 77K (BET surface area of similar to 52 m(2) g(-1)). Moreover, the framework 1' also uptakes different solvent vapours (water, methanol and ethanol) and their type-I profile suggest strong interaction with pore surfaces and overall hydrophilic nature of the framework. Temperature dependent magnetic measurements suggest overall antiferromagnetic behaviour in compound 1.