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The Strandberg polyoxometalate (POM) metallogel Na4(H3O)2[(O2CC2H4PO3)2Mo5O15] (1) was synthesized in which the Strandberg cluster is functionalized by phosphonocarboxylate. The POM gel shows reversible sol to gel transition and gel to gel transition. The multiphase visual transitions between three states as a function of temperature and solvent are scarcely reported. The gel is characterized by temperature‐dependent and frequency‐dependent rheological studies and corresponding xerogels were characterized by FT‐IR, PXRD, FE‐SEM, EDX, TEM, and 31P NMR techniques. The stabilization of gel or obtaining single crystals from the same reaction mixture can be tuned by choice of counter cation. The single crystals of compound Cs14[(HO2CC2H4PO3)2Mo5O15]3·2Cl·10H2O (2) are obtained on addition of CsCl to compound 1 reaction mixture. Compound 2 is characterized by single crystal X‐ray diffraction. The compound 2 crystallizes in I2/a space group with unit cell parameters of a = 24.2415(16) Å, b = 10.4542(6) Å, c = 42.687(3) Å, α = 90°, β = 94.791°(3), and γ = 90°. [ABSTRACT FROM AUTHOR]

• 2, 4-DINITRO BENZOATE COMPLEXES EXHIBIT EXPLOSIVE NATURE OF DECOMPOSTION ON HEATING • PENDENT ALKYL GROUP OF ANCILLARY LIGANDS INFLUENCES THE STRUCTURAL DIVERSITIES • 1D SUPRAMOLECULAR DOUBLE CHAIN MOTIF A series of new metal(II) complexes having general formulae, [M (2, 4-dnb) 2 (L) 2 ] (where 2, 4-dnbH = 2,4-dinitro benzoic acid; M = Co(1), Ni(2), Zn(3) and Cd(4), L = methyl hydrazine carboxylate (mc); M = Co(5), Ni(6), Zn(7) and Cd(8), L = ethyl hydrazine carboxylate (ec)) were prepared and characterized using elemental analysis, UV-Visible, FT-IR, emission spectroscopic and powder XRD techniques. Single crystal X-ray study for 3 and 7 shows that metal ion, in both complexes, adopts distorted MN 2 O 4 geometry arising from a pair of N,O-chelating methyl/ethyl hydrazine carboxylate ligands at equatorial sites and monodendate 2, 4-dnb ions at the axial sites. The pair of nitrogen (or) oxygen atoms of chelating ligands (L) are trans positioned in 3 whereas they are cis positioned in 7. All the complexes exhibit photoluminescence property. On heating all the complexes show explosive nature of decomposition. [Display omitted] [ABSTRACT FROM AUTHOR]

The synthesis, crystal structure, redox characteristics and photochemistry of a new heptamolybdate supported magnesium-aqua coordination complex viz. (hmtH)[{Mg(HO)}{MoO}] ⋅3HO 1 (hmt = hexamethylenetetramine) is reported. The cyclic voltammogram reveals quasireversible redox behaviour while the degradation of rhodamine B (RhB) by 1 under sunlight irradiation indicates its photocatalytic activity. In the crystal structure of 1, two [Mg(HO)] units are linked by a μ-bridging bidentate heptamolybdate ligand resulting in a heptamolybdate supported magnesium-aqua coordinated dianionic complex [{Mg(HO)}{MoO}] charge balanced by two (hmtH) cations. The cations, anions and the lattice water molecules are linked by several hydrogen bonding interactions. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

The structural analysis of a cobalt(III) complex [Co(HL)2](OAc).H2O (1) [H2L = N-(2-hydroxyethyl)-3- methoxysalicylaldimine] reveals a tridentate chelation behaviour of the ligand H2L having a distorted octahedral coordination environment around the cobalt(III) center with a CoN2O4 chromophore. 1 behaves as an effective catalyst towards the oxidation of 3,5-di-tert-butylcatechol in different solvents, viz. dichloromethane (DCM), methanol (MeOH) and acetonitrile (MeCN) to its corresponding quinone derivative in aerial oxygen. The reaction follows Michaelis-Menten enzymatic reaction kinetics with turnover numbers (Kcat), 1.46 × 103, 1.21 × 103 and 2.16 × 103 h-1 in DCM, MeOH and MeCN, respectively. [ABSTRACT FROM AUTHOR]

N-Carbamylmaleamic acid ( malur) undergoes cyclodehydration under favourable conditions, as expected, to give N-carbamyl maleimide. N-(Carboxymethyl) maleamic acid ( malgly), however, does not undergo a similar cyclization reaction. Strong π bonding between the C and N of the amide group as well as two intramolecular hydrogen bonds makes malgly a planar molecule, as revealed by single-crystal X-ray studies. [ABSTRACT FROM AUTHOR]

Highlights: [•] Reaction of urea with thiosemicarbazide is reinvestigated. [•] Urea being an amide does not form any thiosemicarbazone product. [•] Thiosemicarbazide crystallizes in the triclinic space group. [•] Thiosemicarbazide exhibits thione-thiol tautomerism in solution. [•] Thiosemicarbazide exists as the thione tautomer in solid state. [ABSTRACT FROM AUTHOR]

Abstract: The neutral hexadentate Schiff base N-(1-pyridin-2-yl-phenylidene)-N′-[2-({2-[(1-pyridin-2-yl-phenylidene)amino]ethyl}amino)ethyl]ethane-1,2-diamine (L) was used to synthesize new lanthanide(III) complexes of type [M(L)(NCS)3] (M=La, 1; Gd, 2; Tb, 3; Dy, 4). Single crystal X-ray diffractometry reveals the tricapped trigonal prismatic structure of all the compounds. Variable-temperature magnetic susceptibility measurements in 2–4 show the expected χ M T versus T plot for an isolated, mononuclear lanthanide(III) ion with 4f7, 4f8 and 4f9 configurations, respectively following Curie Law. [Copyright &y& Elsevier]

In the crystal structure of the title compound, C12H17N2 +·C7H5O4-, the cations and anions are linked by O—H⋯O, N—H⋯O and C—H⋯O hydrogen bonds, resulting in a homochiral left-handed molecular helical extended structure. The O—H⋯O and N—H⋯O hydrogen bonds are involved in the formation of the helical backbone. The seven-membered ring adopts a half-chair conformation. [ABSTRACT FROM AUTHOR]

We report a novel series of chiral monometallic dithiocarbamate complexes with pendant phenolic groups, formulated as [M{κ2S^S-S2CN(CH2PhOH)(CH(S-CH3))(NaPh)}2] (M = Ni(II) S,S-1, Cu(II) S,S-2, Zn(II) S,S-3) and [M{κ2S^S-S2CN(CH2PhOH)(CH(R-CH3))(NaPh)}2] (M = Ni(II) R,R-4, Cu(II) R,R-5, Zn(II) R,R-6). These compounds were synthesized through a process involving chiral amino precursors S-HL1, R-HL2, CS2 and the corresponding metal acetates. All the compounds have been characterized by microanalysis and standard spectroscopic methods such as 1H and 13C{1H}NMR, IR, UV-visible absorption and EPR spectroscopy. The spectral data suggest a square planar coordination geometry around the nickel(II) and copper(II) centers and a tetrahedral coordination geometry around zinc(II), which is corroborated by density functional theory calculations. The unprecedented molecular structures of imine precursors S-I, R-I and Ni(II)-dithiocarbamate complex S,S-1 were elucidated by single crystal X-ray diffraction (SCXRD), and their crystal packing patterns were studied. Evidently, the change in chirality could not induce changes in the donor–acceptor sites of S-I and R-I, and their molecules are primarily stabilized by O–H⋯N and C–H⋯π interactions, forming a 2D sheet-like structure in the ab-plane. Notably, the chiral S,S-1 complex crystallized in a monomeric achiral space group (triclinic, P1) in which two dithiocarbamate ligands are bonded to the nickel(II) ion in a S^S chelating mode forming a square planar geometry around the metal center. The photophysical properties of all the compounds have been investigated using UV-visible absorption, emission, and thermogravimetric analyses. Compounds exhibited intense blue photoluminescence with maximum emissions in the 330–336 nm region upon excitation in the UV region. A molecular docking study was performed to validate the potentials of these compounds in protein–ligand interactions against B-DNA Dodecamer (PDB Id: 1BNA) and cyclins (PDB Id: 1w98), which are indeed essential proteins of the cell cycle, and their proper functioning is necessary for the human health. [ABSTRACT FROM AUTHOR]

An attempted incorporation of N-donor ligand in the coordination sphere of Ca in the molecular solid [Ca(H2O)4(4-nba)2] (4-nba=4-nitrobenzoate) resulted in the formation of the one-dimensional (1D) coordination polymers catena-[bis(μ-4-nitrobenzoato)-diaqua-calcium 4,4'-bipyridine] 1 and catena-[bis(μ-4-nitrobenzoato)-diaqua-calcium 1H-1,2,4-triazole] 2 with the N-heterocycle functioning as a solvate. The syntheses, crystal structures and properties of [Ca(H2O)2(4-nba)2]·L (L=4,4′-bipyridine 1; L=1H-1,2,4-triazole 2) are reported. The central Ca(II) in 1 and 2 exhibits eight-coordination and the aqua ligands are terminal, while 4-nitrobenzoate functions as a μ2-bridging ligand. The μ2-η2:η1 tridentate binding mode of the 4-nba ligand results in the formation of an infinite chain of edge-sharing {CaO8} polyhedra flanked by the 4-nitrobenzoates. The solvate 4,4′-bipyridine in 1 (or 1,2,4-triazole in 2) links adjacent polymeric chains with the aid of O-H···N hydrogen bonding interactions. A comparative study of {CaOx} polyhedral linking in structurally characterized calcium coordination polymers based on 4-nitrobenzoate is described. [ABSTRACT FROM AUTHOR]

The title compound, [Sr(C7H4NO4)(H2O)7](C7H4NO4)·2H2O, was synthesized from the aqueous reaction of strontium carbonate with 4-nitrobenzoic acid. The structure consists of a nine-coordinate heptaaqua(4-nitrobenzoato-κ2 O, O′)strontium(II) complex cation, an uncoordinated 4-nitrobenzoate anion and two solvent water molecules. The cations, anions and solvent water molecules are linked with the aid of several O—H...O and C—H...O interactions, resulting in a three-dimensional hydrogen-bonding network. The hydrogen bonding between a solvent water molecule and a symmetry-related solvent water molecule results in the formation of a water dimer. [ABSTRACT FROM AUTHOR]

Two new structurally isomeric, 2-(2,4,4-trimethyl-3,4-dihydro-2 H-benzo[ h]chromen-2-yl)-1-naphthol ( 1) and 3-(2,4,4-trimethyl-3,4-dihydro-2 H-benzo[ g]chromen-2-yl)-2-naphthol ( 3) have been synthesized from 2-acetyl-1-naphthol and ethyl-3-hydroxy-2-naphthoate, respectively, involving Grignard reaction, dehydration of the corresponding tertiary alcohols, and hetero Diels-Alder dimerization. The two benzochromenes ( 1 and 3) have been fully characterized by IR, NMR, and HRESIMS data. Their structures are further supported by crystallography of their corresponding acetates ( 2 and 4). J. Heterocyclic Chem., (2011). [ABSTRACT FROM AUTHOR]

Abstract: The reaction of CaCO3 with 2-nitrobenzoic acid (2-nbaH) results in the formation of a coordination polymer, [Ca(2-nba)2(H2O)2] n (1) (2-nba=2-nitrobenzoate), which can be dehydrated to [Ca(2-nba)2] (2). Compound 2 can be rehydrated to 1 on exposure to water vapor. Compounds 1 and 2 were characterized by elemental analysis, IR and UV–Vis spectra, and TG-DSC thermograms. Compound 1 crystallizes in the triclinic space group and its structure consists of an eight coordinated calcium(II), two terminal aqua ligands and two crystallographically independent 2-nba anions, both of which function as μ2–η2:η1 bridging ligands. Each unique 2-nba ligand is linked to Ca(II) in a bidentate fashion via the carboxylate oxygen atoms and is further linked to a symmetry related Ca(II) via one of the oxygen atoms. A pair of such μ2–η2:η1 2-nba ligands are bridged to two symmetry related Ca(II) ions, resulting in the formation of a tricyclic dicalcium-bis(2-nitrobenzoate) moiety, which constitutes the basic building block of the polymer. In the crystal structure of 1, alternating pairs of bridging 2-nba ligands link pairs of {Ca(H2O)2}2+ units into a 1-D polymeric chain extending along the a-axis. The oxygen atoms of the coordinated water, and the carboxylate and nitro groups of 2-nba are involved in O–H···O and C–H···O interactions. [Copyright &y& Elsevier]

The aqueous reaction of barium carbonate with 2-nitrobenzoic acid (2-nbaH) results in the formation of a one-dimensional coordination polymer, catena-poly[[hexa(aqua)dibarium(II)]bis[(μ2-2-nitrobenzoate-O,O,O-NO2)(μ2-2-nitrobenzoate-O,O,O′)]] 1. On heating at 100°C compound 1 is dehydrated to anhydrous barium bis(2-nitrobenzoate) 2. The anhydrous compound can be re-hydrated to 1 on exposure to water vapour. Compounds 1 and 2 were characterized by elemental analysis, IR and UV-Vis spectra, DSC thermograms, weight loss studies and the structure of 1 was determined. 1 and 2 can be thermally decomposed to BaCO3 by heating at 800°C. The polymer [[Ba(H2O)3]2(μ2-2-nba-O,O,O-NO2)2 (μ2-2-nba-O,O,O′)2]n 1 crystallizes in the centrosymmetric triclinic space group Pi and all atoms are located in general positions. The polymeric structure is based on a dimeric unit and consists of three water molecules coordinated to a central Ba(II) and two unique 2-nitrobenzoate (2-nba) anions, one of which (μ2-2-nba-O,O,O-NO2) functions as a tridentate ligand and is linked to a Ba(II) through the oxygen atom of the—NO2 group and forms a monoatomic μ2-carboxylate bridge between two symmetry related Ba(II) ions with a Ba···Ba distance of 4·5726(14) Å. The second unique 2-nba anion (μ2-2-nba-O,O,O′) also functions as a tridentate ligand with the carboxylate oxygen atoms linked to a Ba(II) ion in a bidentate fashion and one of the carboxylate oxygen atoms forming a monoatomic bridge between two symmetry related Ba(II) ions resulting in a Ba···Ba separation of 4·5406(15) Å. These differing tridentate 2-nba ligands link {Ba(H2O)3} units into a one-dimensional polymeric chain extending along b axis. In the infinite chain each nine coordinated Ba(II) is bonded to three water molecules and further linked to six oxygen atoms of four different 2-nitrobenzoate anions with alternating pairs of Ba(II) ions in the chain bridged by a pair of (μ2-2-nba-O,O,O-NO2) and (μ2-2-nba-O,O,O′) ligands resulting in alternating Ba···Ba distances of 4·5406(15) and 4·5726(14) Å across the chain. [ABSTRACT FROM AUTHOR]

The title compound, (C8H12N)2[WS4], was synthesized by the aqueous reaction of ammonium tetrasulfidotungstate(VI) with benzyl(methyl)amine in a 1:2 molar ratio. The compound is isotypic with the corresponding Mo analogue, (C8H12N)2[MoS4], and its structure consists of a slightly distorted tetrahedral [WS4]2- dianion and two crystallographically independent benzyl(methyl)ammonium cations, with all atoms located in general positions. The cations and anion are linked by weak N—H⋯S and C—H⋯S interactions, the strength and number of which can explain the observed W-S bond distances. [ABSTRACT FROM AUTHOR]

Abstract: Copper(II) complexes having the general formula [Cu(L n )2] with the N,O-donor reduced Schiff bases N-(2-hydroxy-5-X-benzyl)-(R)-α-methylbenzylamine and N-(2-hydroxy-5-X-benzyl)-(S)-α-methylbenzylamine (X =Cl and Br) (HL n ) are described. These chiral complexes crystallize in the noncentrosymmetric P212121 (X =Cl) and P21 (X =Br) space groups. In each case, self-assembly via intermolecular C–H⋯O interaction leads to a supramolecular helical superstructure. [Copyright &y& Elsevier]

The reaction of hydrated magnesium or calcium 4-nitrobenzoate (4-nba) generated in situ, with imidazole (Im) results in the formation of the complexes [Mg(H2O)2(Im)2(4-nba)2] 1 and [Ca(H2O)3(Im)(4-nba)2]·Im 2, which exhibit the same metal:4-nba:Im ratio but different degrees of hydration. Complex 1 crystallizes in the triclinic Pī space group and the Mg atom is located on an inversion centre, while 2 crystallizes in the monoclinic P21/c space group and all atoms are located in general positions. In 1 the Im ligands, which are trans to each other, are coordinated to Mg, while 2 contains coordinated as well as free Im. The monodentate 4-nba ligands are disposed trans to each other in 1, while they adopt a cis orientation in 2 resulting in different supramolecular structures. Complex 1 exhibits two types of H-bonding interactions namely O-HΛO and N-HΛO, while in 2 three varieties of H-bond, viz. O-HΛO, N-HΛO and O-HΛN are observed. The Im ligand functions as a bifurcated H-bond donor in 1 while the O atom of the nitro group functions as a H-bond acceptor. In contrast, the nitro group in 2 is not involved in any H-bonding interactions. The free Im in 2 functions as a bifurcated acceptor and forms an extended chain linking adjacent complex molecules. The chains thus formed are further cross-linked with the aid of H-donor bonds from both the free as well as the coordinated Im. Both 1 and 2 exhibit π-π stacking interactions. Complex 1 is thermally more stable as compared to 2, and both complexes can be dehydrated to the corresponding anhydrous complexes by heating at 140 and 100°C respectively. At elevated temperatures, both the complexes can be pyrolysed to the corresponding oxide. The anhydrous complexes can be rehydrated to obtain the starting hydrated materials. [ABSTRACT FROM AUTHOR]

A series of stimuli-responsive AIEgens of tetraphenylethylene (TPE) fused imidazole derivatives (1–7) were synthesized, and their substituent controlled fluorescence properties in the solid state were explored. The structure of the synthesised compounds was characterized by NMR, mass and single crystal X-ray diffraction spectroscopy techniques. 1–7 exhibited a typical aggregation induced emissive (AIE) behaviour in the THF : water mixture. These compounds exhibited substituent dependent strong solid state fluorescence (Φf = 16.6–55.7%) with a tunable λmax between 458 and 496 nm. Chlorine substituted 6 showed the highest fluorescence efficiency (Φf = 55.7%), whereas acetyl substituted 3 exhibited the lowest fluorescence efficiency (Φf = 16.6%). All the seven compounds showed a mechanical pressure induced reversible fluorescence switching. Crushing 1–7 resulted in red shifted fluorescence, which was reversed to its initial state by heating/solvent vapour exposure. Interestingly, integration of 1–7 into a hydrophobic PMMA polymer resulted in blue shifted fluorescence at 470 nm, whereas that into hydrophilic PVA polymer resulted in red shifted fluorescence at 491 nm. Thus highly solid state emissive TPE fused imidazole compounds were prepared, and their stimuli-induced reversible fluorescence switching and polymer controlled tunable fluorescence were demonstrated. [ABSTRACT FROM AUTHOR]

[Display omitted] • New series of piperazine based monometallic and bimetallic bis-dithiocarbamate complexes holding pendant N,O -Schiff base moieties. • Study of crystal packing patterns revealed the formation of 3D multiple open tubular, 3D herringbone and staircase like supramolecular assembly by L1, 1 and 3, respectively. • Investigation of thermal stability, emission behaviour and antimicrobial properties. • DFT study to rationalise the experimental results. Multi-functional ligand precursors 2-[2-(1-piperazinyl)ethyliminomethyl] phenol (L1), 1-[2-(1-piperazinyl)ethyliminomethyl]naphthlene-2-ol (L2) and 6-methoxy-2-[2-(1-piperazinyl)ethyliminomethyl]phenol (L3) were selected to derive a new series of binuclear and mononuclear MII-dithiocarbamate complexes of the type [Cu{κ2S,S-S 2 C-piperazine-C 2 H 4 N=C(H)(R)} 2 ] 2 (R = -Ph(OH) 1 , -Naph(OH) 2 , -Ph(OH)(OCH 3) 3 and [M{κ2S,S-S 2 C-piperazine-C 2 H 4 N = C(H)(R)} 2 ] (R = -Ph(OH), M = NiII 4 , ZnII 5; R = -Naph(OH), M = NiII 6 , ZnII 7; R =- Ph(OH)(OCH 3), M = NiII 8 , ZnII 9). All the compounds have been characterized by microanalysis and standard spectroscopic methods such as 1H and 13C NMR, IR and UV–visible absorption spectroscopy. The molecular structures for L1 and its CuII-/NiII-dithiocarbamate complexes 1 and 4 were elucidated by single crystal X-ray diffraction (SCXRD) and their crystal packing patterns were studied. Interestingly, molecules of L1 forms 3D multiple open tubular supramolecular assembly by involving H bonding and other NH...O C, CH benzene ...O and CH piperazine ...O weak intermolecular forces. Notably, ZnII-dithiocarabamate complexes give maximum emission in visible nm region (ca 444–489) upon excitation of ultraviolet radiation with concomitant Stock shift ca < 200 nm. Thermogravimetric study was performed on 1 – 9 to investigate their thermal stability and degradation patterns. All the compounds have been screened for their potential in vitro antimicrobial activity against by using S. aureus, E. coli and C. albicans by Broth dilution method. The density functional theory calculations have been carried out to reinforce the experimental outcomes. [ABSTRACT FROM AUTHOR]

Potassium salts of phenolate based polydentate xanthate ligands 4,4′-bis(2-dithiocarbonatobenzylideneamino)diphenyl ether (K2xan1) and 4,4′-bis(2-dithiocarbonatonaphthylmethylideneamino)diphenyl ether (K2xan2) have been synthesized and characterized, prior to use. The reaction of K2xan1 or K2xan2 with M(OAc)2 in Et3N affords access to a rare series of binuclear metallomacrocyclic xanthate complexes of the type [M2-μ2-bis-(κ2S,S-xan1/xan2)] (1–4) which quickly forms [2 : 2] binuclear N,O-bidentate Schiff base macrocyclic complexes of the type [M2-μ2-bis-(κ2N,O-L1/L2)] (L1 = 4,4′-bis(2-hydroxybenzylideneamino)diphenyl ether, L2 = 4,4′-bis(2-hydroxynaphthylmethylidene-amino)diphenyl ether) 5–8via evolution of CS2 in solution. The compounds were characterized by microanalysis, relevant spectroscopy (FT-IR, UV-visible), mass spectrometry (ESI-MS), and powder and single crystal XRD techniques. In vitro anticancer activity of all the compounds was evaluated against HEP 3B (hepatoma) and IMR 32 (neuroblastoma) by the MTT assay. Remarkably, the binuclear copper(ii) xanthate complexes were found to be extremely active against both the cell lines (IC50: 8.1 ± 0.8 μM (3), 8.8 ± 1.7 μM (4) against HEP 3B and 1.9 ± 0.3 μM (3) and 7.3 ± 0.6 μM (4) against IMR 32) and this projects them as good candidates for potent antitumor agents and the IC50 values confirm their better potency than the reference drug cisplatin. The flow-cytometric density plot illustrates the induction of apoptosis in HEP 3B and IMR 32 cells after treatment with K2xan1, 1, 3, 6 and 7. [ABSTRACT FROM AUTHOR]

A new monomeric manganese(II) benzoate complex containing nitrogen donor 2,2′-bipyridine, [Mn(OBz) 2 (bipy)(H 2 O)] (OBz = benzoate, bipy = 2,2′-bipyridine) has been synthesized from aqueous methanol medium and characterized by analytical, spectroscopic and single crystal X-ray diffraction studies. The compound exhibits moderate to appreciable antimicrobial activity. The complex crystallizes in space group P2 1 /n. Mn(II) atom is ligated by two N atoms of bipyridine, three O atoms from a monodentate and a bidentate benzoate ligand and a water molecule forming distorted octahedral structure. The coordinated water molecule forms intramolecular hydrogen bonds and links the monomer molecules into hydrogen bonded dimer. The hydrogen bonded dimers are involved in intermolecular C–H···O and π–π stacking interactions. Density functional theory (DFT) computation was carried out to compute the frequencies of relevant vibrational modes and electronic properties, the results are in compliance with the experimentally obtained structural and spectral data. [ABSTRACT FROM AUTHOR]

In this communication, we synthesized a series of twenty four novel 3-(4-(substitutedsulfonyl)piperazin-1-yl)benzo[ d ]isoxazole analogues, characterized using various spectroscopic techniques and evaluated for their in vitro anti-tubercular activity against Mycobacterium tuberculosis (MTB) H 37 Rv strain. The titled compounds exhibited Minimum inhibitory concentration (MIC) between 3.125 and >50 μg/mL. Among the tested compounds, 5c , 6a , 6j and 6p exhibited moderate activity (MIC = 12.5 μg/mL), while 5a and 6i exhibited good activity (MIC = 6.25 μg/mL) and 6b (MIC = 3.125 μg/mL) exhibited very good anti-tubercular activity. In addition, the analogues 5a , 5c , 6a , 6b , 6i , 6j and 6p were subjected to toxicity studies against mouse macrophage (RAW 264.7) cell lines to analyse the selectivity profile of the newly synthesized compounds and selectivity index of the most active compound was found to be >130 indicating suitability of the compound for further drug development. Structure of 6b was further substantiated through single crystal XRD. [ABSTRACT FROM AUTHOR]

A dinuclear Fe(III) complex, [FeIII 2(L)2] (1) [H3L= N,N′-bis(3-methoxysalicylaldimine)-1,3-diaminopropan-2-ol], has been synthesized and characterized using microanalysis, spectroscopy and X-ray crystallography. Structural analysis reveals a pentadentate chelation behaviour of the trianionic ligand H3L, having a distorted octahedral coordination environment around each iron(III) center with an FeN2O4 chromophore. Variable-temperature magnetic susceptibility measurements of 1 indicate an antiferromagnetic interaction between the two iron(III) centers, coupled with J =−28.5. 1 behaves as an effective catalyst towards the oxidation of 3,5-di-tert-butylcatechol in different solvents, viz. methanol, dichloromethane and acetonitrile, to its corresponding quinone derivative in aerial oxygen. The reaction follows Michaelis-Menten enzymatic reaction kinetics with turnover numbers (K cat) 7.51×102, 1.69×103 and 1.23×103 h− 1 in methanol, dichloromethane and acetonitrile, respectively. [ABSTRACT FROM AUTHOR]

Abstract: The reaction of RhCl3 with 1-alkyl-2-(naphthyl-α-azo)imidazole (α-NaiR, N, N′chelator) (R = CH3, CH2–CH3, CH2–Ph) has synthesized a coordination compound, [Rh(α-NaiR-N, N′)(PPh3)Cl3] (2) from boiling methanol in the presence of PPh3 while the reaction under similar condition in the presence of Et3N has synthesized cyclometallated complex, [Rh(α-NaiR-N, N′, C)(PPh3)Cl2] (3). The structures of both types of complexes are confirmed by single crystal X-ray diffraction study in representative cases. All the complexes have been characterized by spectral data (FT-IR, UV–VIS, MS, 1H-NMR) and elemental analyses. Density functional theory calculation has also been performed to rationalize the electronic structures and their spectral properties. [Copyright &y& Elsevier]

Abstract: In this paper we report the synthesis of 4,4′-bis(benzylideneamino)diphenyl ether (1), 4,4′-bis(p-methoxybenzylideneamino)diphenyl ether (2), 4,4′-bis(p-nitrobenzylideneamino)diphenyl ether (3), 4,4′-bis(benzylamino)diphenyl ether (4) and 4,4′-bis(p-methoxybenzylamino)diphenyl ether (5). The new compounds were characterized by using standard spectroscopic techniques. Supramolecular structures of 1–4 have been studied by using single-crystal X-ray diffraction to gauge the influence of substituents, present on para-positions of peripheral phenyl rings, on the association of molecules in the solid state. The study showed that introduction of p-OCH3 and p-NO2 substituents on peripheral phenyl rings, successfully switches off CH⋯π synthons seen in compound 1 and 4 and that the new compounds adopt other packing strategies based on CH⋯O (2) and CH⋯N, CH⋯O and π⋯π (3) interactions. The optical band gaps (Eg), calculated by optical absorption method fall in the range of 2.16–3.0eV and demonstrate a wide band gap semiconducting nature of these compounds. The thermogravimetric study of these compounds suggests the total destruction of the molecules up to 550°C with a remaining mass of <10%, except the 3. [Copyright &y& Elsevier]

Cu(II) complexes with Schiff bases DMIIMP, DMIIMBD, DMIIMBP, DMIIMCP, DMIIMMP, and DMIIMNP (see Introduction for definitions) are derived from condensation of 3,4-dimethyl 5-amino-isoxazole with salicylaldehyde and substituted salicylaldehydes. The newly synthesized ligands were characterized by IR, UV-Vis,1H NMR,13C NMR, mass spectra, and elemental analysis. The Cu(II) complexes were characterized by IR, UV-Vis, ESR, elemental analysis, magnetic moments, thermogram, DTA, and single crystal analysis. The complexes have general formula [M(L)2]. The Schiff bases are bidentate coordinating through the azomethine nitrogen and phenolic oxygen of salicylaldehydes. Based on the analytical and spectral data, four-coordinate geometry is assigned for all the complexes. ESR and single crystal analysis suggests square planar geometry for all complexes. [Cu(DMIIMP)2] crystallizes in the orthorhombic system. Antimicrobial studies of Schiff bases and their metal complexes show significant activity with the metal complexes showing more activity than corresponding Schiff bases. Cytotoxicity of the copper complexes on human cervical carcinoma cells (HeLa) was measured using the Methyl Thiazole Tetrazolium assay. [ABSTRACT FROM AUTHOR]

The title compound, (C8H12N)2[MoS4], was synthesized by the aqueous reaction of ammonium tetrathiomolybdate with benzyl(methyl)amine in a 1:2 molar ratio. The structure consists of a slightly distorted tetrahedral [MoS4]2− dianion and two crystallographically independent benzyl(methyl)ammonium cations, with all atoms located in general positions. The cations and anions are linked by weak N—H...S and C—H...S interactions, the strength and number of which can explain the observed Mo—S bond distances. [ABSTRACT FROM AUTHOR]

Abstract: Ternary Cu(II) complexes [Cu(II)(saltrp)(B)] (1,2), (saltrp=salicylidene tryptophan, B=1,10 phenathroline (1) or 2,2′ bipyridine (2)) were synthesized and characterized. Complex 2 was structurally characterized by single crystal X-ray crystallography. The molecular structure shows a distorted square pyramidal coordination geometry (CuN3O2) in which the ONO donor Schiff base is bonded to the Cu(II) in the basal plane. The N,N donor heterocyclic base displays an axial-equatorial binding mode. CT-DNA binding studies revealed that the complexes show good binding propensity (Intrinsic binding constant, Kb =3.32×105 M−1 for 1 and Kb =3.10×105 M−1 for 2). The catalytic role of these complexes in the oxidative and hydrolytic cleavage of DNA was studied in detail. Complex 1 binds and cleaves DNA more efficiently as compared to 2. From the kinetic experiments, rate constants for the hydrolysis of phosphodiester bond of DNA backbone were determined as 1.94h−1 and 1.05h−1 for 1 and 2 respectively. It amounts to (2.93–5.41)×107 fold rate enhancement compared to uncatalyzed double stranded DNA, which is impressive as compared to related Cu(II) Schiff base complexes. [Copyright &y& Elsevier]

Abstract: In our search for new DNA intercalating ligands, a novel bifunctional intercalator 11-(9-acridinyl)dipyrido[3,2-a:2′,3′-c]phenazine, acdppz (has two potentially effective intercalators via dipyridophenazine(dppz) and acridine which are linked together via C–C bond) and its corresponding Ru(II) polypyridyl complex [Ru(phen)2(acdppz)]2+ (where phen=1,10-phenanthroline) have been synthesized and characterized. The electrochemical behaviors of the ligand and its complex have been thoroughly examined. The structure of acdppz and [Ru(phen)2(acdppz)]2+ were determined by X-ray crystallography. From the crystal structure of the complex, we found that the dppz moiety is not coplanar with the acridine ring, having a dihedral angle of 64.79 in the acdppz. The selected bond lengths and angles for the crystal structure of [Ru(phen)2(acdppz)]2+ were compared to the geometry-optimized molecular structure of [Ru(phen)2(acdppz)]2+ derived by Gaussian. The interaction of [Ru(phen)2(acdppz)]2+ with calf-thymus (CT) DNA was investigated by absorption and viscometry titration, thermal denaturation studies. The above measurements indicated that the complex binds less strongly with the CT DNA due to the intercalation by the ruthenium bound acdppz with an intrinsic binding constant of 2.6×105 M−1. Molecular-modeling studies also support an intercalative mode of binding of the complex to the model duplex d(CGCAATTGCG)2 possibly from the major groove with a slight preference for GC rich region. Additionally, the title complex promotes the cleavage of plasmid pBR322 DNA upon irradiation under aerobic conditions. [Copyright &y& Elsevier]

Abstract: Metal–organic frameworks with the compositions [Zn(bpy)(bdc)(H2O)] n 1, [Zn(bpy)(btec)1/2(H2O)] n 2, [Cd(bpy)(bdc)(H2O)] n 3 and Cd(bpy)(btec)1/2(H2O)] n 4 (H2bdc=1,4-benzenedicarboxylic acid=terephthalic acid, H4btec=1,2,4,5-benzenetetracarboxylic acid and bpy=2,2′-bipyridine) have been synthesized and characterized using spectroscopic and single-crystal X-ray diffraction techniques. In these complexes, ZnII/CdII-2,2′-bipyridine units and carboxylate anions exists as nodes and spacers respectively. An infinite 1D zig-zag chain structure is observed for both complexes 1 and 3, whereas complexes 2 and 4 display a 3D supramolecular architecture. The complexes are found to be photoluminescent, porous and show significant thermal stability. [Copyright &y& Elsevier]

Abstract: The reaction of the monomeric compound [Ca(H2O)4(η1-4-nba)(η2-4-nba)] 1 (4-nba=4-nitrobenzoate) with N-methylimidazole (N-MeIm) or imidazole (Im) at 100 oC results in the formation of the anhydrous mixed ligand complexes of composition [Ca(L)(4-nba)2] (L= N-MeIm 2; L=Im 3). The compounds were characterized by elemental analysis, IR, UV–Vis and 1H NMR spectra, TG-DSC thermograms, weight loss studies and the structure of 2 was determined by single crystal X-ray crystallography. Compounds 2 and 3 can be transformed into 1 by heating with water. At elevated temperatures all compounds (1–3) are thermally decomposed to CaO. Compound 2 crystallizes in the centrosymmetric triclinic space group with all atoms located in general positions. The structure reveals that 2 is a polymer and can be formulated as catena-poly[[(N-methylimidazole)calcium(II)](μ2-η1:η1-4-nitrobenzoato)(μ3-η2:η1-4-nitrobenzoato)]. The structure of [[Ca(N-MeIm)](μ2-η1:η1-4-nba)(μ3-η2:η1-4-nba)] n 2 consists of a central Ca(II) ion, a terminal N-MeIm ligand and two crystallographically independent 4-nba ligands. In the crystal structure, each Ca(II) is bonded to a nitrogen atom of N-MeIm and five oxygen atoms from five symmetry related 4-nba ligands resulting in a distorted {CaO5N} octahedron. One of the unique 4-nitrobenzoate in each formula unit functions as a bridging bidentate ligand (μ2-η1:η1-4-nba) and is linked to two symmetry related Ca(II) ions leading to the formation of an infinite chain extending along a axis with a long Ca⋯Ca separation of 5.531(1)Å. The second independent 4-nba ligand (μ3-η2:η1-4-nba) is coordinated to three different Ca(II) ions with both the carboxylate oxygen atoms linked to the same infinite chain formed earlier and one of the carboxylate oxygen atoms functions as a monoatomic bridge between two symmetry related Ca(II) ions. This bridge links two chains with a shorter Ca⋯Ca separation of 3.8585(7)Å resulting in the formation of a one-dimensional ladder structure. The oxygen atoms of the nitro groups are involved in C–H⋯O interactions. A comparative study of 30 Ca(II) coordination polymers is described. [Copyright &y& Elsevier]

The reaction of barium carbonate with 4-nitrobenzoic acid (4-nbaH) results in the formation of a Ba(II) coordination polymer, catena-poly[[(pentaaqua) (4-nitrobenzoato-O,O')barium(II)] (μ-4-nitrobenzoato-O,O')] 1. The polymeric compound [[Ba(H2O)5(4-nba-O,O')]( μ-4-nba-O,O')]n1 was characterized by elemental analysis, IR and UV--Vis spectra, weight loss studies, X-ray powder diffraction and its structure determined. In 1 five water molecules are coordinated to the central metal and one of the 4-nba ligands is bonded to Ba(II) in a bidentate manner (4-nba-O,O') through the carboxylate O atoms. The [(pentaaqua)(4-nitrobenzoato-O,O')barium(II)] units are linked into an infinite one-dimensional chain along b-axis with the aid of the second 4-nba anion, which functions as a bridging bidentate (μ -4-nba-O,O') ligand. This results in nine coordination around each Ba(II) ion in the coordination polymer. A long Ba⋯Ba distance of 6.750(1) Å is observed between adjacent Ba(II) ions in the chain and the oxygen atoms of the carboxylate group and the nitro functionalities of the 4-nba ligand are involved in several O-H⋯O and C-H⋯O interactions. .KWT-Keywords: [ABSTRACT FROM AUTHOR]

Synthesis of novel 1,2,3-selena/thiadiazoles, linked to different benzo-1,3-heteroazole ring by sulfur has been reported. Structural features of the compounds have been analyzed by 1H and 13C NMR, mass and single crystal X-ray studies. [ABSTRACT FROM AUTHOR]

The title compound, C10H18O7S2, was synthesized by reacting diethylene glycol with allyl chlorosulfonate in the presence of pyridine. The asymmetric unit consists of half a molecule, which is located on a twofold rotation axis. In the crystal structure, the molecules are involved in several weak C—H...O interactions. [ABSTRACT FROM AUTHOR]