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The design and development of alloy catalysts has been a focus of intense interest because suitable selection and control over the composition of alloy catalysts can result in greatly improved activity and selectivity, while it is unusual that the combination of two inactive metals gives a highly active catalyst. In this work, we found that Ni-Pt bimetallic nanocatalysts, with a platinum content as tow as 7 mol %, prepared by the coreduction of the corresponding metal chiondes, exhibit excellent catalytic activity to the decomposition of hydrous hydrazine, producing hydrogen with a 100% selectivity at room temperature, whereas the corresponding single-component nickel and platinum counterparts are inactive for this reaction. These results provide new possibilities for searching heterometaltic catalysts. The present catalyst with tow noble-metal content promotes the practical use of the hydrogen-storage system based on the catalytic complete decomposition of hydrazine in aqueous solution at ambient conditions. [ABSTRACT FROM AUTHOR]

By introducing the flexible 1,4-bis(1,2,4-triazol-1-ylmethyl)benzene (L[sup1]) and 1,4-bis(imidazole-1-ylmethyl)benzene (L[sup2]) ligands into the molybdate system under hydrothermal conditions, 12 novel isopolymolybdate frameworks were obtained: [CuL[sup1](H[sub2]O)][Mo[sub3]O[sub10]] (1), [ML[sup1](H[sub2]O)[sub2]][Mo[sub3]O[sub10]] [M= Cu(2),Zn (3), and Co (4)], [Cu[sub2](L[sup1])[sub4]][θ∙Mo[sub8]O[sub26]] (5), [Cu[sub4](L[sup1])[sub4]]-[β∙Mo[sub8]O[sub26]][sub0.5][γ∙Mo[sub8]O[sub26]][sub0.5]∙H[sub2]O (6), [Ag[sub4](L[sup1])[sub2]][β∙Mo[sub8]O[sub26]] (7), [M[sub2](L[sup1])[sub3](H[sub2]O)[sub4]][β∙Mo[sub8]O[sub26]]∙2H[sub2]O [M=Zn (8), Co (9), and Ni (10)], and [M[sub4](L[sup2])[sub4]][δ∙Mo[sub8]O[sub26]][M=Cu (11) and Ag(12)]. Compound 1 and isosturctural compounds 2-4 exhibit similar three-dimensional (3D) pillar-layered structures. Compound 5 shows a novel pillar-layered framework constructed from two sorts of [CuL[sup1]][subn] left- and right-handed chains and the θ∙[Mo[sub8]O[sub26]][sup4-] polyoxoanion. Compound 6 contains two sorts of isomers of β-[Mo[sub8]O[sub26]][sup4-] and γ-[Mo[sub8]O[sub26]][sup4-] coexisting in one structure, which induce the formation of two sorts of ladderlike building blocks and finally the polythread structure. The cationic and anionic fragments in compound 7, the dinuclear molecular loop of [Ag[sub2](Lsup1])[sub2]][sup2+] and β∙[Mo[sub8]O[sub26]][sup4-], are both linked up by single Ag ions, forming two kinds of infinite chains of [Ag[sub3](L[sup1])[sub2]][subn][sup3n+] and [Ag-β-Mo[sub8]O[sub26]][subn][sup3n-], respectively. Compounds 8-10 are isostructural and exhibit the parallel two-fold (2D→2D) interpenetrated networks based on the β-[Mo[sub8]O[sub26]][sup4-] cluster. Isostructural compounds 11 and 12 have 3D polythread penetrated frameworks based on the δ-[Mo[sub8]O[sub26]][sup4-] polyoxoanion. The luminescent properties of the ligands and complexes 3, 6-8, and 11-12 are investigated in the solid state. [ABSTRACT FROM AUTHOR]

Reactions of laser-ablated tin and lead atoms with nitric oxide molecules in solid argon and neon have been investigated using matrix-isolation infrared spectroscopy. In the argon experiments, absorptions at 1560.1, 1625.8, and 1486.7 cm-1 are assigned to the N-O stretching vibrations of the SnNO and Sn(NO)2 molecules, and absorptions at 1541.9, 1630.0, 1481.8, and 1457.5 cm-1 are assigned to the N-O stretching vibrations of the PbNO, Pb(NO)2, and PbNO- molecules on the basis of isotopic shifts and splitting patterns. The present neon experiments only produce neutral tin and lead mononitrosyls. Density functional theory calculations have been performed on these tin and lead nitrosyls. The good agreement between the experimental and calculated vibrational frequencies, relative absorption intensities, and isotopic shifts substantiates the identification of these nitrosyls from the matrix infrared spectra. [ABSTRACT FROM AUTHOR]

The tungsten and molybdenum hexacarbonyls, M(CO)[sub 6] (M = W, Mo), dissolve in fluorosulfonic acid, HSO[sub 3]F, to generate the tungsten and molybdenum carbonyl cations, [M(CO)[sub 4]][sup 2+](solv), which are transformed, by exposure to an NO atmosphere, into the tungsten and molybdenum carbonyldinitrosyl cations, [M(CO)(NO)[sub 2]][sup 2+](solv), respectively. These complexes have been characterized by NMR ([sup 183]W, [sup 13]C, and [sup 15]N), IR, and Raman spectroscopy, and they are the first well-characterized metal nitrosyl cations in strong acids or superacids although the spectroscopic techniques do not address the number or coordination mode of the solvent molecules. Their formation suggests that strong acids and superacids can hopefully be used to generate a number of metal nitrosyl cations as they have been successfully used for preparing a series of metal carbonyl cations. [ABSTRACT FROM AUTHOR]

The syntheses of heteroleptic dipyrrinato nickel(II) complexes [Ni(4-pydpm)(dedtc)] (1) and [Ni(4-pydpm)(dipdtc)] (2) [4-pydpm = 5-(4-pyridyl)dipyrromethene; dedtc = diethyldithiocarabamate; and dipdtc = diisopropyldithiocarbamate] and the thorough characterization of these complexes by satisfactory elemental analyses, electrospray ionization mass spectrometry, Fourier-transform infrared, NMR (¹H, 13C), and UV-vis spectroscopies, and electrochemical studies was achieved. Structure of 1 was authenticated by X-ray single-crystal analysis. Both the complexes 1 and 2 were successfully utilized as a capping agent in the preparation of silver nanoparticles. Availability of free pyridyl nitrogen on the dipyrrin core of these complexes was meticulously exploited in functionalization and stabilization of the silver nanoparticles (AgNPs). Morphological and structural investigations on colloidal nanoparticles were followed by UV-vis spectroscopy and transmission electron microscopy (TEM). Overall results revealed that average size of the silver nanoparticles (~10, 15, 20 nm, and aggregation) is strongly influenced by ratio of Ag/[1/2] (03, 06, 10, 20). Correlation between particle size and capping agents was realized by UV-vis and TEM studies. Catalytic activity of the AgNPs obtained through this route was successfully employed in the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP). It was established that reduction process follows a pseudo-first-order kinetics. [ABSTRACT FROM AUTHOR]

The rigid and angular tetracarboxylic acid 1,3-bis(3,5-dicarboxyphenyl)imidazolium (H4L+), incorporating an imidazolium group, has been used with different pyridine-based linkers to construct a series of non-interpenetrated cationic frameworks, {[Zn2(L)(bpy)2]·(NO3)·(DMF)6·(H2O)9}n (1), {[Zn2(L)(dpe)2]·(NO3)·(DMF)3·(H2O)2}n (2), and {[Zn2(L)(bpb)2]·(NO3)·(DMF)3·(H2O)4}n (3) [L = L3-, DMF = N,N'-dimethylformamide, bpy = 4,4'-bipyridine, dpe = 1,2-di(4-pyridyl) ethylene, bpb = 1,4-bis(4-pyridyl)benzene]. The frameworks consist of {[Zn2(L)]+}n two-dimensional layers that are further pillared by the linker ligands to form three-dimensional bipillared-layer porous structures. While the choice of the bent carboxylic acid ligand and formation of double pillars are major factors in achieving charged non-interpenetrated frameworks, lengths of the pillar linkers direct the pore modulation. Accordingly, the N2 gas adsorption capacity of the activated frameworks (1a-3a) increases with increasing pillar length. Moreover, variation in the electronic environment and marked difference in the pore sizes of frameworks permit selective CO2 adsorption over N2, where 3a exhibits the highest selectivity. In contrast, the selectivity of CO2 over CH4 is reversed and follows the order 1a > 2a > 3a. These results demonstrate that even though the pore sizes of the frameworks are large enough compared to the kinetic diameters of the excluded gas molecules, the electronic environment is crucial for the selective sorption of CO2. [ABSTRACT FROM AUTHOR]

Syntheses and characterizations of the arene ruthenium [(η6-C6H6)RuCl(4-mtdpm)] (1), [(η6-p-MeC6H4Pri)RuCl(4-mtdpm)] (2), and structurally analogous rhodium/iridium complexes [(η5-C5Me5)RhCl(4-mtdpm)] (3) and [(η5-C5Me5)IrCl(4-mtdpm)] (4) [4-mtdpm = 5-(4-methylthiophenyl)dipyrromethene] have been reported. Their identities have been established by satisfactory elemental analyses, electrospray ionization-mass spectrometry (ESI-MS), FT-IR, NMR (¹H, 13C), UV/vis, emission spectral, and electrochemical studies. Structure of the representative complex 3 has been authenticated by X-ray single crystal analyses. The complexes 1-4 effectively bind with calf thymus DNA (CT DNA) through intercalative/electrostatic interactions. In addition, these exhibit significant cytotoxicity toward Dalton lymphoma (DL) cell line and cause static quenching of the bovine serum albumin (BSA) fluorophore. The antiproliferative activity, morphological changes, and apoptosis have been evaluated by MTT assay, acridine orange/ethidium bromide (AO/EtBr) fluorescence staining, and DNA ladder assay. Mode of interaction of the complexes with DNA/protein has also been supported by molecular docking. Various studies revealed remarkable decrease in the in vitro DL cell proliferation and induction of the apoptosis by 1-4, which lies in the order 2 > 1 > 4 > 3. [ABSTRACT FROM AUTHOR]

The synthesis of four novel heteroleptic dipyrrinato complexes [(rj6- arene)RuCl(2-pcdpm)] {rf-arene = C6H6, 1; C10HI4, 2) and [(5-C5Me5)MCl(2-pcdpm)] (M = Rh, 3; Ir, 4) containing a new chelating ligand 4-(2-methoxypyridyl)-phenyldipyrromethene (2-pcdpm) have been described. The complexes 1--4 have been fully characterized by various physicochemical techniques, namely, elemental analyses, spectral (ESI-MS, IR, *H, 13C NMR, UV/vis) and electrochemical studies (cyclic voltammetry (CV) and differential pulse voltammetry (DPV)). Structures of 3 and 4 have been determined crystallographically. In vitro antiproliferative and cytotoxic activity of these complexes has been evaluated by trypan blue exclusion assay, cell morphology, apoptosis, acridine orange/ethidium bromide (AO/EtBr) fluorescence staining, and DNA fragmentation assay in Dalton lymphoma (DL) cell lines. Interaction of 1--4 with calf thymus DNA (CT DNA) has also been supported by absorption titration and electrochemical studies. Our results suggest that in vitro antitumor activity of 1--4 lies in the order 2 > 1 > 4 > 3. [ABSTRACT FROM AUTHOR]

Six heteroleptic dipyrrinato complexes [Ni(fcdpm)(dedtc)] (1), [Ni(fcdpm)(dipdtc)] (2), [Ni(fcdpm)(dbdtc)] (3), [Pd(fcdpm)(dedtc)] (4), [Pd(fcdpm)(dipdtc)] (5), and [Pd(fcdpm)(dbdtc)] (6) (fcdpm = 5-ferrocenyldipyrromethene; dedtc = diethyldithiocarbamate; dipdtc = diisopropyldithiocarbamate; dbdtc = dibutyldithiocarbamate) have been synthesized and characterized by elemental analyses and spectral (ESI-MS, IR, 1H, 13C NMR, UV-vis) and electrochemical studies. Crystal structures of 1, 2, 4, and 5 have been authenticated by X-ray single-crystal analyses. Nickel-based complexes 1--3 display selective chromogenic and redox sensing for Hg2+ and Pb2+ ions, while palladium complexes 4--6 display selective chromogenic and redox sensing only for Hg2+. Electronic absorption, ESI-MS, and electrochemical studies indicated that sensing arises from interaction between 1--3 and Hg2+/Pb2+ through sulfur of the coordinated dithiocarbamates, while it arises from the pyrrolic nitrogen of fcdpm and dithiocarbamate sulfur from 4--6 and Hg2+. Different modes of binding between Ni and Pd complexes have further been supported by theoretical studies. The receptor--cation binding constants (Ka) and stoichiometry between probes and Hg2+/ Pb2+ have been estimated by the Benesi--Hildebrand method and Job's plot analysis. Detection limits for 1--3 toward Hg2+/Pb2+ and 4--6 for Hg2+ have been found to be reasonably high. [ABSTRACT FROM AUTHOR]

In this work, for the first time, we have systematically demonstrated that solvent plays crucial roles in both controllable synthesis of metal--organic frameworks (MOFs) and their structural transformation process. With solvent as the only variable, five new MOFs with different structures have been constructed, in which one MOF undergoes solventinduced single-crystal to single-crystal (SCSC) transformation that involves not only solvent exchange but also the cleavage and formation of coordination bonds. Particularly, a significant crystallographic change has been realized through an unprecedented three-step SCSC transformation process. Furthermore, we have demonstrated that the obtained MOF could be an excellent host for chromophores such as Alq3 for modulated luminescent properties. [ABSTRACT FROM AUTHOR]

In this paper, two kinds of Ni nanoparticles have been successfully synthesized without and with starch as the "green" protective material and investigated as catalysts for generating hydrogen from ammonia borane (NH3BH3, AB). Experimental investigations have demonstrated that both of the Ni nanoparticles possess high activities fo H2 generation from aqueous solution of AB. However, the catalytic activities of Ni nanoparticles without starch decrease seriously in the course of the lifetime tests. In contrast, the catalytic activities of the Ni nanoparticles with starch almost keep unchanged even after 240 h. Moreover, the XPS results show that the surface of the Ni nanoparticles in starch solution is still metallic Ni even after 240 h, while that in pure water is nickel oxide. This means that starch can successfully keep the Ni nanoparticles in aqueous solution from the oxidation in air. The present efficient, low-cost, and longtime water/air stable Ni catalyst represents a promising step toward the development of AB as a viable on-board hydrogen storage and supply material. [ABSTRACT FROM AUTHOR]

Oxime targeted reactions of the complexes trans-[(K3-dapdOH)Ru(CO)(PPh3)2]PF6 (1) (dapdoH = diacetylpy- ridinedioxime) and trans-[(K3-dapmOH)RuCI(PPh3)2]PF6 (2) (dapm0H = diacetylpyridinemonooxime) with SOCI2, NaBH4, or HCHO led into conversion of oxime to oximato, imino, or hydroxymethylimino groups. The reaction products have been characterized by analytical and spectral studies. Molecular structures of the representative homo/heteroleptic oxime/oximato complexes trans-[(K3-dapdOH)Ru(CO)(PPh3)2]PF6 (1), trans-[(K3-dapdO)Ru- (CO)(PPh3)2] (11) and oximato/imino complex trans-[(K3-dapd-NH)Ru(CO)(PPh3)2]PF6 (13) have been authenticated by single-crystal X-ray diffraction analyses. Structural studies revealed the presence of various oxime/oximato/ imino based O-H...O, C-H...O, and N-H. .F interactions in the complexes 1, 11, and 13. [ABSTRACT FROM AUTHOR]

Reactions of laser-ablated lanthanoid atoms (except for radioactive Pm) with carbon dioxide molecules in solid argon have been investigated using matrix-isolation infrared spectroscopy. On the basis of isotopic shifts, mixed isotopic splitting patterns, and CCl4-doping experiments, the lanthanoid oxocarbonyl complexes have been identified. Density functional theory calculations have been performed on these products, which support the experimental assignments of the infrared spectra. Infrared spectroscopic studies of these lanthanoid complexes combined with theoretical calculations reveal that the early lanthanoid (La-Sm) oxocarbonyl complexes adopt trans configurations, the europium and ytterbium ones adopt side-on-bonded modes (Eu-(η²-OC)O and Yb-(η²-OC)O), and the late lanthanoid (Gd-Lu) ones adopt cis configurations. Natural bond orbital analysis indicates that the formation of the lanthanoid oxocarbonyl complexes involves the promotion of 6s and 4f electrons into the metal valence shell. [ABSTRACT FROM AUTHOR]

A highly water soluble 3:2 complex of copper(ll) and 2,4,6-tris(di-2-pyridylamine)-1,3,5-triazine (TDAT) has been synthesized and structurally characterized. The complex crystallized in a triclinic P1 space group with a molecular formula of [Cu3(TDAT)2Cl3]Cl3·2H2O (1), where each copper ion is coordinated by four pyridine nitrogen atoms and an apical chloride. The trinuclear complex is stable at physiological relevant conditions. It can bind to DNA through electrostatic attraction and cleave efficiently the supercoiled pBR322 DNA into its nicked and linear forms at micromolar concentrations. Active oxygen intermediates such as hydroxyl radicals and singlet oxygen generated in the presence of 1 may act as active species for the DNA scission. [ABSTRACT FROM AUTHOR]

Four novel ZnII and CdII metal-organic coordination polymers with a versatile building block 5-(4-pyridyl)-1,3,4-oxadiazole-2-thiol (Hpyt) have been prepared under different conditions. (Zn3(pyt)4(OH)2]n (1) and [Cd(pyt)(HCOO)]n (3) were obtained through a solvothermal method, whereas {[Zn(pyt)2(H2O)2]•(DMF)2}n (2) and {[Cd(pyt)2]CHCl3}n (4) were isolated under general conditions. X-ray single-crystal diffraction indicates that the anionic ligand pyt adopts a thioamide isomer in 1, 2, and 4, but a thiolate form in 3. Four types of binding modes involving monodentate (η-Noxa), bidentate (μ-Npy,Noxa, or μ-NpyS,S) and tridentate (μ-Npy,Noxa,S) are observed. The discrepancy of the synthetic routes and metal-coordination preferences facilitates the production of the final crystalline materials with distinct network structures, including a 1D zigzag array of 1 with dangling arms, a common 2D (4,4) coordination layer of 2, a decorated 3D α-Po network of 3, and an unprecedented (3,6)-connected 3D framework of 4 with a (4².6)2(4².6².87.10²) topology. Notably, the hydrolysis of DMF solvates leads to the formation of formate ions, being a component in the structure of 3. Complexes 2 and 4 show 1D channels in which the solvates are accommodated, and even after the exclusion of these guests, the porous host frameworks are still retained. Thermal stability and gas adsorption properties have also been studied. [ABSTRACT FROM AUTHOR]

A novel trinuclear copper(Il) complex, Cu3-L (L -- N,N,N',N',N",N"-hexakis(2-pyridyl)-l,3,5-tris(aminomethyl)benzene), exhibited efficient oxidative strand scission of plasmid DNA. The solution behavior of the complex has been studied by potentiometric titration, UV spectroscopy, and cyclic voltammetry. The data showed that there are three redox-active copper ions in the complex with three types of bound water. The complex demonstrated a moderate binding ability for DNA. Cu3-L readily cleaves plasmid DNA in the presence of ascorbate to give nicked (form II) and then linear (form III) products, while the cleavage efficiency using H2O2 is less than by ascorbate, suggesting that the cleavage mode of the trinuclear complex is somewhat different from the traditional Fenton-like catalysis. Meanwhile, Cu3-L is far more efficient than its mononuclear analogue Cu-DPA (DPA -- 2,2'-dipyridylamine) at the same [Cu2+] concentration, which suggests a possible synergy between the three or at least two Cu(ll) centers in Cu3-L that contributes to its relatively high nucleolytic efficiency. Furthermore, the presence of standard radical scavengers does not have clear effect on the cleavage efficiency, suggesting the reactive intermediates leading to DNA cleavage are not freely diffusible radicals. [ABSTRACT FROM AUTHOR]

Reports on the synthesis of a series of oxo complexes with formula Re(O)X(diyne) (X = I, Me, Et), from 2,7-nonadiyne and Re(O)I[sub 3]-PPh[sub 3)[sub 2]. Oxo ligand coordination to boron; Protonation of Re(O)X(2-butyne)[sub 2] and Re(O)(X)(2,7-nonadiyne)[sub 2] with a variety of acids and resulting compounds; Protonation kinetics; Conformations.