Can enantiomer ligands produce structurally distinct homochiral MOFs?

Abstract

Here, we report a self-assembled homochiral metal-organic framework [Cu 1.5 IJH 2 L L-leu )IJAc)H 2 O] n ·3H 2 O (1) obtained from an L-leucine-derived ligand (H 4 L L-leu ) and CuIJAc) 2 ·H 2 O in a 1 : 1 ratio. Coordination-induced conformational change in the ligand has been monitored by circular dichroism which has been further attested by synthesizing a D-leucine-containing enantiomer H 4 L D-leu and its CuIJII) complex [Cu 1.5 IJH 2 L D-leu )H 2 O] n ·10H 2 O (2). Structure determination revealed entirely different structures for the homochiral MOFs (1 and 2) obtained from the L/D-leucine-derived enantiomer ligands under analogous reaction conditions. Further, structural dissimilarity in these MOFs has been judicially supported by proton conductance studies. MOF 1 shows higher proton (10 −5 S cm −1 ) conductance in comparison to 2 (10 −6 S cm −1 ) due to dissimilar alignment of the hydrogen-bonded water molecules in the hydrophilic pocket as well as crystal packing. CrystEngCommThis journal is