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

Abstract

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 Fe₂(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 × 3.5, 1.5 × 0.5 and 2.2 × 2.1 Ų) occupied by the guest water and ethanol molecules. Framework 1 shows high thermal stability, and the desolvated framework (1 ) renders permanent porosity realized by N₂ adsorption pro- file at 77 K (BET surface area of ∼52 m² 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.