The First Highly Stable Homochiral Olefin−Copper(I) 2D Coordination Polymer Grid Based on Quinine as a Building Block

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.

Modulating the ferroelectric performance by altering halogen anions in the crystals of tetranuclear copper-clusters

The ferroelectric performance of tetranuclear copper clusters can be modulated by altering the free halogen anions existing in the crystal structure.

Cinchona Alkaloids-Derivatives and Applications

Major Cinchona alkaloids quinine, quinidine, cinchonine, and cinchonidine are available chiral natural compounds (chiral pool). Unlike many other natural products, these alkaloids are available in multiple diastereomeric forms which are separated on an industrial scale. The introduction discusses in short conformational equilibria, traditional separation scheme, biosynthesis, and de novo chemical syntheses. The second section concerns useful chemical applications of the alkaloids as chiral recognition agents and effective chiral catalysts. Besides the Sharpless ethers and quaternary ammonium salts (chiral PTC), the most successful bifunctional organocatalysts are based on 9-amino derivatives: thioureas and squaramides. The third section reports the main transformations of Cinchona alkaloids. This covers reactions of the 9-hydroxyl group with the retention or inversion of configuration. Specific Cinchona rearrangements enlarging [2.2.2]bicycle of quinuclidine to [3.2.2] products are connected to the 9-OH substitution. The syntheses of numerous esterification and etherification products are described, including many examples of bi-Cinchona alkaloid ethers. Further derivatives comprise 9-N-substituted compounds. The amino group is introduced via an azido function with the inversion of configuration at the stereogenic center C9. The 9-epi-amino-alkaloids provide imines, amides, imides, thioureas, and squaramides. The syntheses of 9-carbon-, 9-sulfur-, and 9-selenium-substituted derivatives are discussed. Oxidation of the hydroxyl group of any alkaloid gives ketones, which can be selectively reduced, reacted with Grignard reagents, or subjected to the Corey-Chaykovsky reaction. The alkaloids were also partially degraded by splitting C4'-C9 or N1-C8 bonds. In order to immobilize Cinchona alkaloids the transformations of the 3-vinyl group were often exploited. Finally, miscellaneous functionalizations of quinuclidine, quinoline, and examples of various metal complexes of the alkaloids are considered.

catena-Poly[1,4-dihydroxy-1,4-diazoniabicyclo[2.2.2]octane [aquatri-μ-chlorido-trichloridodicuprate(II)]]

The title compound, {(C6H14N2O2)[Cu2Cl6(H2O)]}n, consists of 1,4-dihydroxy-1,4-diazoniabicyclo[2.2.2]octane dications and one-dimensional inorganic anionic {[Cu2Cl6(H2O)](2-)}n chains in which both five-coordinate [CuCl3(H2O)](-) and five-coordinate [CuCl3](-) units exist. These two distinct type of unit are linked together by one chloride ion and are bridged across centres of inversion to further units of their own type through two chloride ions, giving rise to novel polymeric zigzag chains parallel to the c axis. The chains are connected by O-H···Cl hydrogen bonds to produce R2(4)(16) ring motifs, resulting in two-dimensional layers parallel to the ac plane. These layers are linked into a three-dimensional framework with the organic cations via O-H···Cl hydrogen bonds. Hydrogen bonding between the chains, and between the chains and the organic cations, provides stability to the crystal structure.

2-[(R)-Hydroxy(6-methoxyquinolinium-4-yl)methyl]-8-vinyl-1-azoniabicyclo[2.2.2]octane tetrachloridoferrate(III) chloride monohydrate

In the title salt, (C₂₀H₂₆N₂O₂)[FeCl₄]Cl·H₂O, the Fe^III atom exists in a tetra­hedral coordination environment. The cation, anions and water mol­ecules are linked by N—H⋯Cl, O—H⋯Cl and O—H⋯O hydrogen bonds into a layer network.

The first metal-organic framework (MOF) of Imazethapyr and its SHG, piezoelectric and ferroelectric properties

Hydrothermal reaction of H-Imazethapyr (2-(4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl)-5-ethyl-3-pyridinecarboxylic acid) with Cd(ClO4)2.6H2O offers a diamond-like MOF Cd(Imazethapyr)2 in which it crystallizes in a non-centrosymmetric space group (Fdd2) belonging to polar point group (C2v). MOF displays a strong SHG response, and good ferroelectric and piezoelectric properties.

Homochiral 1D Zinc−Quitenine Coordination Polymer with a High Dielectric Constant

Heat treatment of a solution of MeOH and water containing the quitenine ligand HQA [HQA = 6-methoxyl-(8S,9R)-cinchonan-9-ol-3-carboxylic acid] and ZnCl2 at 70 degrees C to give the one-dimensional (1D) chain coordination polymer {(HQA)(ZnCl2)(2.5H2O)}n (1). The local coordination geometry around the zinc center in 1 displays a slightly distorted tetrahedron, with the HQA ligand adopting a zwitterionic moiety similar to that found in natural amino acids. Measurements on a powdered sample of 1 reveal a strong second-harmonic-generation response of ca. 20 times larger than that for KDP (KH2PO4). Notably, measurements on the dielectric properties of 1 showed that the 1D chain coordination polymer exhibited a dipolar chain relaxation process and a high dielectric constant (epsilon0= 37.3).

A Second-Order Nonlinear Optical Material Prepared through In Situ Hydrothermal Ligand Synthesis

The in situ hydrothermal reactions of ZnCl(2) with benzonitrile, 2-amino-5-cyanopyridine, and trans-2,3-dihydro-2-(4' '-cyanophenyl)-benzo[e]indole in the presence of NaN(3) and water afford two 3D-diamond-like networks, (CN(4)-C(6)H(5))(2)Zn (1) and (NH(2)-C(5)H(3)N-CN(4))(2)Zn (2), and one 2D square grid network, [(CN(4)-C(6)H(4)-C(12)H(7)N-C(5)H(4)N)(2)Zn].1.5H(2)O (3), in which these ligands gradually involve a noncenter-A-D (acceptor-donor) system, a one-center-A-D system, and a two-center-A-D system, respectively. All three compounds crystallize in noncentrosymmetric space groups (I2d for 1 and 2 and Fdd2 for 3) and display strong second harmonic generation (SHG) responses. Among the three new complexes, 3 shows the largest SHG effect, which is about 50 and 500 times that of urea and KDP (KH(2)PO(4)), respectively. The two-center-A-D system (multicenter push-pull electronic effect) in 3 may be responsible for it having the largest SHG effect. Interestingly, the three compounds exhibit strong fluorescent emissions at different wavelengths, 1 and 2 with blue fluorescent emissions at 390 and 415 nm and 3 with yellow-green fluorescent emissions at 495 and 532 nm.

The First Metal (Nd3+, Mn2+, and Pb2+) Coordination Compounds of 3,5-Dinitrotyrosine and their Nonlinear Optical Properties

The reactions of 3,5-dinitrotyrosine (H2DNTY) with Nd(NO3)3.6H2O, Mn(ClO4)2.6H2O, and Pb(OAc)2 afforded three homochiral compounds: discrete [Nd(Hdnty)2(NO3)(H2O)5].3H2O (1) and two- and three-dimensional coordination polymers, [Mn(Hdnty)2] (2) and [Pb(dnty)(0.5 H2O)] (3), respectively. The Nd atom in 1 displays a tricapped trigonal prism and supramolecular weak interactions, such as pi-pi stacking and H-bonds, between amino and nitro groups result in the formation of a three-dimensional network through these interactions. 2 has a two-dimensional square-grid topological net while 3 has the first three-dimensional homochiral ThSi2 net. To the best of our knowledge, these are the first metal coordination compounds with 3,5-dinitrotyrosine. Preliminary second harmonic generation (SHG) investigations indicated that 1 and 2 are SHG active with estimated responses 5 and 6 times larger than that of urea, respectively, while 3 is SHG non-active (obeying the Klainman symmetry requirement). Strong enhancement of their SHG efficiency, compared with H2DNTY, may be due to 1) the addition of a good donor-pi-acceptor organic chromophore into the compound resulting in superior qualities of both inorganic and organic materials and 2) the H-bonds that persist in them. Crystal data: 1: C18H32N7O25Nd, Mr = 890.75 g mol(-1), monoclinic, P2(1), a=7.0179(7), b=27.060(3), c=8.3097(8) A, alpha=gamma=90.00, beta=95.646(2) degrees , V=1570.4(3) A(3), Z=2, rho(calcd)=1.884 Mg m(-3), R(1)=0.0489, wR(2)=0.1223, mu=17.67 mm(-1), S=0.811, Flack value=0.003(13); 2: C(18)H(16)N(6)O(14)Mn, M(r)=595.31 g mol(-1), orthorhombic, P2(1)2(1)2, a=8.4381(14), b=13.639(2), c=19.697(3) A, alpha=beta=gamma=90.00 degrees , V=2266.9(6) A(3), Z=4, rho(calcd)=1.744 Mg m(-3), R(1)=0.0866, wR(2)=0.2030, mu=6.72 mm(-1), S=1.095, Flack value=0.02(6); 3: C(9)H(8)N(3)O(7.5)Pb, M(r)=485.37 g mol(-1), tetragonal, P4(1)2(1)2, a=12.8136(12), b=12.8136(12), c=14.931(2), alpha=beta=gamma=90.00 degrees , V=2451.5(5) A(3), Z=8, rho(calcd)=1.885 Mg m(-3), R(1)=0.0564, wR(2)=0.1323, mu=6.942 mm(-1), S=0.878, Flack value=0.03(2). For space group P4(3)2(1)2: R(1)=0.0672, wR(2)=0.1656, S=1.034, Flack value=1.02(3); this suggests the chosen space group P4(1)2(1)2 is correct.

Strong enhancement of second-harmonic generation (SHG) response through multi-chiral centers and metal-coordination

The hydrothermal reaction of CdCl2 with L (L =trans-2,3-dihydro-2-(4'-pyridyl)-3-(3"-cyanophenyl)benzo[e]indole) in the presence of NaN3 and water offers a novel route to [Cd(L-N3)2(H2O)2]n, a 1D infinite molecular box with approximate dimensions 10.37 x 6.64 è; 1 is shown to display a very strong SHG response that is 80 times that observed for urea.

Highly stable olefin–Cu(i) coordination oligomers and polymers

Highly stable Cu(I)-olefin coordination oligomers and polymers have been successfully prepared and applied to construct metal-organic frameworks (MOFs) with interesting physical and chemical functions in recent years. In this review, we present the olefin-Cu(I) coordination oligomers and polymers and their novel physical properties. From structure to functions, particular emphasis is placed on the coordination and organometallic chemistry of olefin-Cu(I) coordination oligomers and polymers, their structures and potential applications as solids possessing unusual physical functional properties such as electrochemical, chiral separation, fluorescent sensing and ferroelectricity.

A Novel TGS-like Inorganic−Organic Hybrid and a Preliminary Investigation of Its Possible Ferroelectric Behavior

The homochiral inorganic-organic hybrid compound (H(3)NHPA)(SnCl(3))(2)(H(2)O)(3) [1, (S)-4-(4'-aminophenyl)-2-aminobutanoic acid diammonium trichloride stannite triaqua] has a TGS (triglycine sulfate)-like structure. Preliminary investigation suggests a possible ferroelectric behavior with a saturation spontaneous polarization (P(s)) of ca. 3.5 microC.cm(-)(2), which is slightly greater than that of TGS (P(s) = 3.0 microC.cm(-)(2)).