Tuning Structural Topologies of a Series of Metal–Organic Frameworks: Different Bent Dicarboxylates

Abstract

Five new metal–organic frameworks incorporating the angular tetratopic ligand with different transition metal ions and bent coligands have been synthesized: [Zn4(L)2(4,4′-sdb)4(H2O)2]·3H2O (1), [Zn2(L)2(hfipbb)2(H2O)3] (2), [Zn(L)(oba)]·H2O (3), [Cd2(L)2(4,4′-sdb)2]·2H2O (4), [Cd2(L)(hfipbb)(H2O)3]·2H2O (5), [L = 1,1′-oxybis[3,5-dipyridine-benzene, 4,4′-H2sdb = 4,4′-sulfonyldibenzoate, H2hfipbb = 4,4′-(hexafluoroisopropylidene)bis(benzoic acid), H2oba = 4,4′-oxybis(benzoate)]. Structural analysis reveals that the mixed ligands display versatile coordination modes to manage the metal ions to form homochiral, inclined polycatenation (1D → 2D), 3-fold interpenetrating nets. However, the different coordinated modes, geometry, and flexibility of ligands around metal ions result in subtle differences in the final architecture. Bulk materials for 1 and 3 have a second-harmonic generation activity, approximately 0.4 and 0.8 times that of urea.