Chiral Metal-Organic Frameworks

In the past two decades, metal-organic frameworks (MOFs) or porous coordination polymers (PCPs) assembled from metal ions or clusters and organic linkers via metal-ligand coordination bonds have captivated significant scientific interest on account of their high crystallinity, exceptional porosity, and tunable pore size, high modularity, and diverse functionality. The opportunity to achieve functional porous materials by design with promising properties, unattainable for solid-state materials in general, distinguishes MOFs from other classes of materials, in particular, traditional porous materials such as activated carbon, silica, and zeolites, thereby leading to complementary properties. Scientists have conducted intense research in the production of chiral MOF (CMOF) materials for specific applications including but not limited to chiral recognition, separation, and catalysis since the discovery of the first functional CMOF (i.e., d- or l-POST-1). At present, CMOFs have become interdisciplinary between chirality chemistry, coordination chemistry, and material chemistry, which involve in many subjects including chemistry, physics, optics, medicine, pharmacology, biology, crystal engineering, environmental science, etc. In this review, we will systematically summarize the recent progress of CMOFs regarding design strategies, synthetic approaches, and cutting-edge applications. In particular, we will highlight the successful implementation of CMOFs in asymmetric catalysis, enantioselective separation, enantioselective recognition, and sensing. We envision that this review will provide readers a good understanding of CMOF chemistry and, more importantly, facilitate research endeavors for the rational design of multifunctional CMOFs and their industrial implementation.

Synthesis, Structures, and Properties of Four Novel HgII Complexes Based on Pyridine Acylamide Ligands

In this work we synthesised four new pyridine acylamide complexes [HgI2(L1)] (1) and (2), [HgI2(L2)2] (3), and [HgI2(L3)]n (4) (L1 = N,N′-bis(3-pyridylmethyl)benzene-1,4-dicarboxamide, L2 = N4,N4′-bis(pyridin-3-yl)-[1,1′-biphenyl]-4,4′-dicarboxamide, L3 = N1,N3-bis(pyridin-3-ylmethyl)isophthalamide) by solvo(hydro)thermal reaction. Compounds 1 and 2 are supramolecular isomers prepared via variation of the reaction solvent, in which the HgII centres are bridged by L1 ligands to form one-dimensional (1D) helical chain or 1D meso-helical chain, respectively. Careful inspection of the structures reveal that formation of the isomers are mainly induced by the distinct configuration of L1 ligand and slight differences in coordination geometry of the HgII ions. Complex 3 shows a novel Z-shaped zero-dimensional structure with a L2–HgI2–L2–HgI2–L2 arrangement. In complex 4, flexible L3 ligands link HgI2 units to construct a 1D helical chain with an overall chiral structure, derived from spontaneous resolution. Luminescence properties of these four novel complexes were also explored.

Multi odd–even effects on cell parameters, melting points, and optical properties of chiral crystal solids based on S-naproxen

Chiral solids based on S-naproxen alternatively crystallize in P2₁ and P2₁2₁2₁, respectively, which show the odd–even effects on cell parameters, melting points, and luminescence.

Ethane-1,2-diaminium bis-{5-[4-(1H-tetra-zol-5-yl)phen-yl]tetra-zolide} dihydrate

In the two anions of the title salt, C(2)H(10)N(2) (2+)·2C(8)H(5)N(8) (-)·2H(2)O, the central aromatic rings make dihedral angles of 13.53 (6) and 6.53 (7)° with the deprotonated tetra-zole rings, and 11.39 (6) and 10.41 (9)° with the other tetra-zole groups. In the crystal, the cations, anions and water mol-ecules are linked by an extensive O-H⋯N, N-H⋯O and N-H⋯N hydrogen-bond network into two-dimensional wave-like duplex sheets extending parallel to the bc plane. π-π stacking inter-actions between benzene rings [inter-centroid distances are 3.8482 (4) and 3.9621 (5) Å] and between tetra-zole rings [inter-centroid distances are 3.4350 (4) and 3.7169 (4) Å] further consolidate the crystal structure.