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Reaction of the bent dicarboxylate ligand H2OBA (H2OBA = 4,4′-oxybisbenzoic acid) and the flexible linker 1,4-bis(3-pyridyl)-2,3-diaza-1,3-butadiene (L1), under diverse reaction conditions, forms two polymorphic Co(ii) coordination polymers (CPs): {[Co(OBA)(L1)]·DMF}n (1), as a three dimensional (3D) framework with a pcu alpha-Po primitive cubic topology, and {[Co(OBA)(L1)]·DMF}n, (2), as a two dimensional (2D) structure with a 6-c uninodal net topology. Gas adsorption measurements of the desolvated Co(ii) CPs show negligible uptake of all gases in 1, while 2 exhibits moderate uptake of CO2, with good selectivity over N2 and CH4. With Zn(ii), reaction of H2OBA and L1 produces a different 2D CP, {[Zn0.5(OBA)0.5(L1)0.5]}n (3). Finally, three isostructural Cd(ii) CPs, {[Cd(OBA)(L1)]·DMF}n (4), {[Cd(OBA)(L1)]·DEF}n (5), and {[Cd(OBA)(L1)]·DMA}n (6) (DMF = N,N-dimethylformamide, DEF = N,N-diethylformamide, DMA = N,N-dimethylacetamide), that differ only in the lattice solvent molecules and show 2D structural arrangements are prepared. Interestingly, CP 4 undergoes single-crystal to single-crystal (SC-SC) transmetallation reaction at room temperature, yielding isostructural {[Cu(OBA)(L1)]·DMF}n (7) that cannot be synthesized independently. Moreover, the luminescence properties of compounds 1, 2, 3, and 4 have been studied in the solid state at room temperature. All the complexes are characterized by elemental analysis, IR, TGA, PXRD and single crystal X-ray diffraction.

Porous activated carbon was modified with (1E,2E)-1,2-bis(pyridin-4-ylmethylene)hydrazine (M) and (1E,2E)-1,2-bis(pyridin-3-ylmethylene)hydrazine (SCH-4). Characterization was performed using different techniques such as SEM, FTIR and 1H NMR analysis. Then, these new adsorbents were used for the efficient removal of Europhtal (sulfonated cobalt phthalocyanine). Response surface methodology (RSM) was used to achieve operational conditions for the efficient removal of Europhtal using an activated carbon modified with novel ligands. To investigate the individual effect of variables involved and the effect of their possible interactions on the adsorption process, several systematic experiments were designed by varying the variables such as pH, sonication time, adsorbent dosage and dye concentration in the range of 2.0-11, 2-8 min, 0.005-0.035 g and 4-30 mg L-1, respectively. The optimum values of pH, sonication time, adsorbent dosage and Europhtal concentration were found to be 7, 2 min, 30 mg L-1 and 0.03 g for the sample modified with M and 7, 5 min, 30 mg L-1 and 0.03 g for the one modified with SCH-4, at which the removal percentages were more than 98%. Adsorption equilibrium data were well fitted to the Freundlich model with maximum adsorption capacities of 56.69 and 17.84 mg g-1 for M and SCH-4, respectively. The study of adsorption kinetics indicated that the dye uptake process follows the pseudo second-order and saturation type rate expressions for each ligand.

Three different N, N′-donor ligands with Zn(NO3)2·6H2O and two different dicarboxylates, flexible succinate (suc) and rigid fumarate (fum) afforded six different metal-organic frameworks (MOFs). Among the N, N′-donor ligands, one bent 1, 4-bis(3-pyridyl)-2, 3-diaza-1, 3-butadiene (3-bpdb) gives two isostructural two-dimensional MOFs, {[Zn(3-bpdb)(suc)]·(H2O)2}n (1) and {[Zn(3- bpdb)(fum)(H2O)2]}n (2). The use of a straight N, N′-donor ligand, i.e., 1, 4-bis(4- pyridyl)-2, 3-diaza-1, 3-butadiene (4-bpdb), results in two three-dimensional (3D) MOFs, {[Zn4(4-bpdb)2(suc)3(OH)2]·5(H2O)}n (3) and {[Zn(4-bpdb)(fum)]·(H2O)2}n (4). Here, 3 is a pillared layer structure, whereas 4 has a 5-fold interpenetrated dimondoid network. For both the bent and straight N, N′-donor ligands an imine alike motif is embedded in the structure. When this motif is replaced by a C-C double bond by using the ligand 1, 2-bis(4-pyridyl)ethylene (bpee), it produces two MOFs, {[Zn(bpee)(suc)]2·(H2O)3}n (5) and {[Zn2(bpee)2(fum)2]·(H2O)}n (6), having a similar structural relation like 3 and 4 respectively, 5 with a pillared layer structure and 6 with a 5-fold interpenetrated diamondoid network. All the compounds have been thoroughly characterized by powder X-ray diffraction (PXRD), elemental analysis, infrared (IR) spectroscopy, UV-vis spectroscopy, and thermogravimetric analyses. Gas/solvent vapor sorption studies have been carried out for compounds 3-6, which have 3D structures. In the case of 3, an interesting reversible crystalline to crystalline transformation was observed which has been thoroughly studied by PXRD analysis, IR spectroscopy, and UV-vis spectroscopy. Solid state emission spectral analysis for all the complexes was performed at room temperature.

Abstract: Metal-organic 1D coordination polymers of Zn(II) and Cd(II), [{Zn(3-Bphz)(H2O)4}(3-Bphz)(NO3)2]n (I), [Zn(3-Bphz)I2]n (II), [Cd(3-Bphz)I2]n (III), [Cd(4-Bphz)(CH3COO)2(H2O)]n (IV), and [Cd(4-Bphz)(NO3)2(H2O)2]n (V), containing azines of the N,N' type, 1,2-bis(pyridin-3-ylmethylene)hydrazine (3-Bphz) and 1,2-bis(pyridin-4-ylmethylene)hydrazine (4-Bphz), as bridging ligands are synthesized. The compositions and structures of the compounds are confirmed by the data of elemental analysis, IR and NMR spectroscopy, and single-crystal X-ray diffraction analysis (CIF files CCDC nos.?1812634–1812638 for I–V). Coordination polymers I–III have zigzag structures. The octahedral environment of the Zn2+ ion in compound I is formed by two 3-Bphz ligands and four water molecules. The external sphere contains nitrate anions and uncoordinated 3-Bphz molecules. In isomorphous compounds II and III, the tetrahedral environment of the metal is formed by two nitrogen atoms of two bridging 3-Bphz ligands and two iodine atoms. Coordination polymers IV and V are linear. The coordination polyhedron of the Cd2+ ion in?compound IV is a pentagonal bipyramid, two vertices of which are occupied by the nitrogen atoms of two 4-Bphz molecules, and the equatorial plane is formed by two bidentate-chelating acetate anions and one water molecule. In compound V, the octahedral environment of the Сd2+ ion is formed by two molecules of the 4-Bphz ligand, two monodentate nitrate anions, and two water molecules. All complexes are weak luminophores emitting in the blue-green spectral range.

A series of Schiff’s base derivatives was rationally designed, synthesized, and evaluated as multi-function agents for the treatment of Alzheimer’s disease (AD). The results revealed that compound 3b was a novel multifunctional agent. It acted as a highly selective monoamine oxidase-B inhibitor (IC50 = 8.4 nM), which was explained by the docking study. Compound 3b also was an antioxidant agent (2.3 eq) and could significantly inhibit self-induced Aβ1-42 aggregation (31.8%). Meanwhile, compound 3b was a selective metal chelator and could inhibit Cu2+-induced Aβ1-42 aggregation (62.3%). Furthermore, compound 3b presented good neuroprotective effects on H2O2-induced PC12 cell injury. More importantly, compound demonstrated good blood brain barrier permeability and druglike properties. Therefore, compound 3b, a promising multi-targeted active molecule, offers an attractive starting point for further study in the drug-discovery process against AD.[Figure not available: see fulltext.].

A practical four-step synthesis of pymetrozine is reported, starting from a green chemical dimethyl carbonate and using the key intermediate methyl (E)-1-(2-oxopropyl)-2-(pyridin-3-ylmethylene)hydrazine-1-carboxylate. The main advantages of the route include inexpensive starting materials, environmental friendliness, short synthetic route, easy-to-use synthetic method and acceptable overall yield. A scale-up experiment was carried out to provide pymetrozine with 99.84% purity in 53.2% total yield.

The solid-state structures of a series of azine or azo chromophore containing bipyridyl ligand complexes of Ag(i) salts have been determined by single-crystal X-ray diffraction. The supramolecular structures are dominated by one-dimensional chains formed through pyridyl-Ag-pyridyl bonding, but the packing of these chains through non-covalent intermolecular interactions is unpredictable. Ag...anion interactions are shown to be important, especially for nitrate and perchlorate species, but these may be supported or replaced by Ag...Ag, Ag...solvent, Ag...azine or Ag...π contacts. The molecular structures of the ligands show little alteration on complex formation, except for the AgNO3 complex of N,N′-bis-pyridin-4-ylmethylenehydrazine where the normally planar azine ligand adopts a twisted geometry. The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2005.

The first reduction chemistry of the high explosive RDX that allows subsequent functionalization into a SERRS active species.

Bis(pyridynyl-2,3-dihydrooxadiazolyl)benzenes 51-e and 9a, b are obtained in 25-85 percent yields by heating the corresponding bis(hydrazones) 4a-f and 8a, d in refluxing Ac2O-AcOH for 3-5 h, while the bishydrazones 19 and 17b give 33-54 percent yields of the phthalazine derivatives 20a, b upon heating in refluxing ethanol containing acetic acid.

The thermal decompositions of sodium salts of tosylhydrazones of furfural, thiophene-2-aldehyde, 1-methylpyrrole-2-aldehyde, and pyridine-2-aldehyde in the presence of silver chromate gave 2-furyl(p-toluenesulfonyl)methane, thiophene-2-(p-toluenesulfonyl)methane, 1-methylpyrrole-2-(p-toluenesulfonyl)methane, and pyridine-2-(p-toluenesulfonyl)methane, respectively, via 1,3 NC migration of tosyl group.The same type of reactions with sodium salts of tosylhydrazones of thiophene-3-aldehyde, pyridine-3-aldehyde, and pyridine-4-aldehyde also afforded the corresponding p-toluenesulfonylmethanes but the yields were slightly lower comparing to the above cases.

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