Samarium Diiodide Catalyzed Synthesis of 2,3-Dihydro-1H-benzo[b][1,4]-diazepine Derivatives

Two different anionic manganese(II) coordination polymers constructed through dicyanamide coordination bridges

In order to explore new metal coordination polymers and to search for new types of ferroelectrics among hybrid coordination polymers, two manganese dicyanamide complexes, poly[tetramethylammonium [di-μ3-dicyanamido-κ6N1:N3:N5-tri-μ2-dicyanamido-κ6N1:N5-dimanganese(II)]], {[(CH3)4N][Mn2(NCNCN)5]}n, (I), andcatena-poly[bis(butyltriphenylphosphonium) [[(dicyanamido-κN1)manganese(II)]-di-μ2-dicyanamido-κ4N1:N5]], {[(C4H9)(C6H5)3P]2[Mn(NCNCN)4]}n, (II), were synthesized in aqueous solution. In (I), one MnIIcation is octahedrally coordinated by six nitrile N atoms from six anionic dicyanamide (dca) ligands, while the second MnIIcation is coordinated by four nitrile N atoms and two amide N atoms from six anionic dca ligands. Neighbouring MnIIcations are linked together by μ-1,5- and μ-1,3,5-bridging dca anions to form a three-dimensional polymeric structure. The anionic framework exhibits a solvent-accessible void of 289.8 Å3, amounting to 28.0% of the total unit-cell volume. Each of the cavities in the network is occupied by only one tetramethylammonium cation. In (II), each MnIIcation is octahedrally coordinated by six nitrile N atoms from six dca ligands. Neighbouring MnIIcations are linked together by double dca bridges to form a one-dimensional polymeric chain, and C—H...N hydrogen-bonding interactions are involved in the formation of the one-dimensional layer structure.

Ionic liquid/water mixture promoted organic transformations

Wet ILs constitutes a new class of solvents with their own new and interesting properties. The IL–water mixing makes it easy to control the properties of the solution and the formation of these ionic liquid mixtures increases synthetic flexibility.

Sodium tetrachloroaurate(III) dihydrate-catalyzed efficient synthesis of 1,5-benzodiazepine and quinoxaline derivatives

Both 1,5-benzodiazepine and quinoxaline derivatives are important heterocycles in pharmaceuticals. We describe an efficient and clean method for the synthesis of 1,5-benzodiazepines from o-phenylenediamine and ketones catalyzed by sodium tetrachloroaurate(III) dihydrate under mild conditions. The catalyst was shown to be equally effective for the synthesis of quinoxalines from o-phenylenediamine and alpha-bromo ketones under the similar reaction conditions. This method produced good yields.

Molecular Tectonics of Metal–Organic Frameworks (MOFs): A Rational Design Strategy for Unusual Mixed-Connected Network Topologies

To systematically explore the higher-dimensional network structures with mixed connectivity, a series of two-dimensional (2D) and three-dimensional (3D) metal-organic frameworks (MOFs) with unusual (3,6)-connected net topologies are presented. These crystalline materials include [{[Mn(btza)2(H2O)2].2 H2O}n] (1), [{[Zn(btza)2(H2O)2].2 H2O}n] (2), [{[Cu(btza)2].H2O}n] (3), and [{[Cd(btza)2].3 H2O}n] (4), which have been successfully assembled through a predesigned three-connected organic component bis(1,2,4-triazol-1-yl)acetate (btza) with a variety of octahedral metal cores based on the modular synthetic methodology. The topological paradigms shown in this work cover the 2D CdCl2, 3D (4(2).6)2(4(4).6(2).8(7).10(2)), and pyrite (pyr) types. That is, when properly treated with the familiar first-row divalent metal ions, btza may perfectly furnish the coordination spheres for effective connectivity to result in diverse (3,6)-connected nets. Beyond this, a detailed analysis of network topology for all known 3D (3,6)-connected frameworks in both inorganic and inorganic-organic hybrid materials is described. Specific network connectivity of these MOFs indicates that the metal centers represent the most significant and alterable factor in structural assembly, although they show reliable and similar geometries. In this context, the combination of the distinct d10 AgI ion with btza in different solvents affords two isomorphous MOFs [{[Ag(btza)].glycol}n] (5) and [{[Ag(btza)]CH3OH}n] (6) with a binodal 4-connected 3D SrAl2 (sra) topology. The network structures of MOFs 1-3 and 5 turn out to be more complicated and interesting if one considers the hydrogen bonding between the host coordination frameworks and the intercalated solvent molecules. Furthermore, the role of the included solvents in the generation and stabilization of MOFs 1-6 is also investigated.