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New anthracene derived dinuclear Au(I)-diacetylide complex (1) has been synthesized in which two Au(I) units are attached at 9,10-positions of ethynyl anthracene moiety. 1 exhibits rare non-covalent intermolecular Au center dot center dot center dot H-C interactions, leading to the formation of a supramolecular 2D-network. Further, to understand the effect of C CAuPPh3 units at different position, complexes (2) and (3) were synthesized, where C CAuPPh3 units are attached to 2,6-and 1,8-positions of anthracene, respectively. The absorption and emission spectra of 1-3 have been studied and surprisingly 1 was found to be highly fluorescent with high quantum yield compared to 2 and 3, this may be due to more perturbation of Au(I) on pi system. Complexes 1-3 have been characterized by elemental analysis, NMR and Mass spectroscopy and authenticated by their single-crystal X-ray structures. (C) 2016 Elsevier B.V. All rights reserved.

We report the synthesis of six new heteroleptic Hg(II) complexes (1–6) with general composition [Hg(II)(bpy)L2] where bpy = 2,2′-bipyridine, L = benzoic acid (1), 2-amino benzoic acid (2), 3-amino benzoic acid (3), 4-amino benzoic acid (4), 2-hydroxy benzoic acid (5), 4-hydroxy benzoic acid (6). 1, 2, 4–6 are monomer with hexa coordinated Hg(II) center whereas 3 is a zig–zag 1D-polymer with hepta-coordinated Hg(II) ion. Unlike other substituted benzoic acids, the 3-amino benzoic acid shows both –NH2 and –COOH groups having affinity towards Hg(II) centers. Therefore, on reaction of HgCl2/HgBr2 with 3-amino benzoic acid it was observed that only –NH2 group coordinates to Hg(II) center and –COOH group remains uncoordinated yielding 7 and 8. 1–6 have been characterized by elemental analysis, FT-IR, thermo gravimetric analysis as well as single crystal X-ray studies. Their photo-physical properties were also investigated and maximum quantum yield was observed for 3. Polymer 3 exhibited different fluorescence spectra in different solvents with maximum emission in chloroform. The electronic communication and geometry optimization have been performed by Density Functional Theory.

The present study deals with the synthesis of ZnO nanoflowers (ZnO-1 and ZnO-2) at room temperature using new structurally characterized single molecular precursors (1 and 2). 1, 2 and ZnO-1 were explored for their potential to reduce the viability of the Gram-negative bacteria Escherichia coli.1 and 2 were found to be promising antibacterial agents, while the ZnO nanoflowers demonstrated a relatively non-toxic nature. 1, 2 and ZnO-1 were further evaluated for DNA binding and cleavage behaviour. 1 and 2 showed strong binding affinity towards CT-DNA compared to ZnO-1. In addition, all the three compounds demonstrated oxidative cleavage of pBluescript plasmid DNA in the presence of H2O2.

A cobalt-based nanocomposite (CoNC) has been prepared from a recently reported single source molecular precursor (SSMP) [CoII(hep-H)(H2O)4]SO4 (A) (hep-H = 2-(2-hydroxylethyl)pyridine). The resulting nanocomposite material was characterized by using various physicochemical techniques such as XRD, SEM, EDAX, TEM and XPS spectroscopy. X-ray diffraction patterns show the weakly crystalline nature of the catalyst. This was also confirmed by the SAED pattern obtained from HR-TEM. XPS analysis reveals the formation of metallic cobalt and the cobalt oxide (CoO) nanocomposite. CoNC was employed for the facile catalytic hydrogenation of 2-nitrotriptycene (M1) and 2,6,14-trinitrotriptycene (M2) as model substrates under atmospheric reaction conditions, which otherwise takes place either with RANEY® Nickel, Pd/C or SnCl2/HCl catalysts under harsh conditions. The mechanistic pathway reveals that the reduction of M1 proceeds via the intermediacy of azoxy triptycene (III) and N-hydroxylamine triptycene (IV).

A metastable heterometallic intermediate, [Cu2(bpy)2(DIPSA)2Hg2(OAc)4(DIPSA)2]n (1, where OAc = CH3COO(-), bpy = bipyridine, and DIPSA = diisopropylsalicylic acid), has been isolated and characterized during the synthesis of 1D polymer [Cu2(bpy)2(DIPSA)2(CH3CN)2Hg2(OAc)2(DIPSA)4]n (2) at ambient temperature in acetonitrile. Moreover, recrystallization of 2 in methanol results in monomeric [Cu(DIPSA)(bpy)(CH3OH)]·CH3OH (3). Complexes 1-3 have been characterized by elemental analysis, Fourier transform infrared, and UV-vis spectroscopy as well as by their single-crystal X-ray structures. The photophysical study suggests the quenching of fluorescence of DIPSA upon complexation.

Reaction of CdCl2 with hep-H [hep-H = 2-(2-hydroxyethyl)pyridine] in MeOH at 298 K yields the double open cubane tetramer [Cd2(μ-Cl)2(μ3-Cl)(hep-H)2Cl]2 (1). 1 on reaction with methanolic HCl, HNO3, and H2SO4 transforms into a one-dimensional (1D) polymeric chain [Cd(μ2-Cl)2(Cl)(hep-H2)]n (2), ribbon-shaped polymeric structure [[Cd5Cl12(H2O)3](hep-H2)2]n (3), and three-dimensional network [Cd(SO4)(H2O)]n (4) with topology seh-4,6-C2/c net, respectively. The similar reactions of CdCl2 with other pyridine alcohols such as hmp-H [hmp-H = 2-(2-hydroxymethyl)pyridine] and hpp-H [hpp-H = 2-(2-hydroxypropyl)pyridine] yield 1D polymeric chains [Cd(μ2-Cl)2(hmp-H)]n (5) and [Cd(μ2-Cl)2(hpp-H)]n (6), respectively. Similar to 1, upon treatment with methanolic HCl 5 and 6 also transform into respective 1D polymeric chains [Cd2(μ2-Cl)4(Cl)2(hmp-H2)2]n (7) and [Cd(μ2-Cl)2(Cl)(hpp-H2)]n (8), analogous to 2. However, their reactions with methanolic HNO3 and H2SO4 result in nonisolable products. In 1, 5, and 6, the pyridin...

A new imine conjugate Schiff base ligand (H2L) was prepared and evaluated for its sensing properties. H2L detects Zn2+ selectively among the wide range of metal ions. The sensing behavior of H2L was identified by UV-vis, fluorescence and 1H NMR titration. H2L shows fluorescence switch ON with the Zn2+ ion among 18 other metal/heavy metal ions with a detection limit of 1.47 μM. The binding of Zn2+ was confirmed by single crystal X-ray studies, which reveal the formation of binuclear complex (1). The packing diagram of H2L reveals the presence of rare linear C–H⋯C interactions (bond distance 2.79 A and bond angle 180°) which form 1D-polymeric chains. Furthermore, the cytotoxicity of H2L and 1 has been assessed against MCF-7 and A375 cell lines and both are found to have marginal toxicity.

Reactions of n-butyl- and n-octyl-thiophene with CS2 at 0 °C resulted in thiolate dimers 1 and 2, respectively. The reaction of 1 with Cu(NO3)2·3H2O in methanol under ambient reaction conditions yielded monomeric [CuII{(n-C4H9(C4H2S)CS2O}2] (3). 1 and 3 were authenticated by their single-crystal X-ray crystal structures. Crystal structure of 3 revealed cleavage of the S-S bond of 1 followed by insertion of O-atom, forming a new five-membered Cu–O–S–C–S metallacycle. 1, 2, and 3 were further investigated for their bioactivity through molecular docking with nine different proteins having medicinal implications. Molecular docking of 1, 2 and 3 revealed considerable interaction with different proteins viz. cancer protein Tankyrase 2, influenza viral protein Polymerase subunit PAC–PB1N complex (H5N1), Polymerase subunit PA endonuclease (H1N1), Polymerase subunit PAn Apo(avian influenza), and FTSZ (Bacillus subtilis). Comparatively, 1 has promising application in therapeutics as compared to 2 and 3 based on its inhibitory constant and binding energy. Density functional theory calculations were performed to better understand the bonding of complex using MO diagram in 1–3. Moreover, TDDFT calculations were performed to facilitate the assignment of electronic transitions of UV–Vis spectra.

Reactions of the amide ligand, H2L (H2L = N,N'-bis[2-(2-pyridyl)methyl]pyridine-2,6-dicarboxamide) with CdCl2 and Hg(CH3COO)2, in 1 : 1 ratio, at 298 K yield dimeric [Hg(L)]2 (1) and trimeric [Cd3(H2L)4Cl6] (2), respectively. In 1, the H2L is coordinated to Hg(II) via six N-atoms of central and terminal pyridines as well as of deprotonated amido groups, whereas the carbonyl groups remain free. However, in 2, the H2L is coordinated to Cd(II) through terminal pyridine N atoms and O atoms from carbonyl groups, whereas the nitrogen atoms of the central pyridine, two terminal pyridine and of all amido groups remain free. Molecular structures of 1 and 2 are confirmed by single crystal X-ray studies. The varying coordination modes of H2L give rise to different electrochemical behavior of 1 and 2, which has also been rationalized by theoretical calculations. Moreover, nonlinear optical (NLO) behavior of both complexes has been investigated using ultra-short femtosecond laser pulses, which ensures that the NLO response is exclusively from their electronic component.

The structure of the centrosymmetric title complex, [Cu(C5H9O2)2(C6H7NO)2], has the CuIIatom on a centre of inversion. The CuIIatom is six-coordinate with a distorted octahedral geometry, defined by the N and O atoms of the chelating 2-(2-hydroxymethyl)pyridine ligands and two carboxylate O atoms from two monodentate pivalate ions. The crystal packing is stabilized by intermolecular C—H...O and intramolecular O—H...O hydrogen-bond interactions.

The synthesis, characterization and photoswitching behavior of a new salen type Schiff base N,N'-bis(2-hydroxy-5-phenylazobenzilidene)-2,4,6-trimethylbenzene-1,3-diamine (H₂L) and a binuclear zinc(ii) metallacycle [{Zn(L)}2·2H2O] (1) have been described. Both H₂L and 1 have been characterized by satisfactory elemental analyses, spectral (FT-IR, (1)H, (13)C NMR, ESI-MS, electronic absorption, emission) and electrochemical studies. Crystal structures of both H₂L and 1 have been authenticated by single crystal X-ray diffraction analyses. These exhibit trans-cis photoisomerization upon exposure to UV light (365 nm) and get back to a more stable trans-form after withdrawal of the light. Electronic absorption, emission, (1)H NMR and cyclic voltammetric studies revealed that trans-cis isomerization in metallacycle 1 is rather rapid (~5.0 s) relative to H₂L (~25 s) which has been supported by theoretical studies (DFT). Relatively fast photoisomerization in 1 compared to H₂L is facilitated by a small energy gap between HOMO levels of the trans- and cis-isomers. The percentage trans-cis conversion ratio for both H₂L and 1 has been evaluated (55-45, H₂L; 60-40%, 1) by (1)H NMR studies.

A novel C-C coupled 1D-polymeric chain (1) is obtained by reaction of HgCl2 and hmp-H (2-(2-hydroxymethyl pyridine)) (1 : 1) in MeOH at ambient temperature. However, a new class of μ-oxo and μ-chloro bridged polymers (2) has been obtained by altering the metal : ligand ratio to 1 : 2.