719261-06-0Relevant articles and documents
NiO nanoparticles prepared via thermal decomposition of the bis(dimethylglyoximato)nickel(II) complex: A novel reusable heterogeneous catalyst for fast and efficient microwave-assisted reduction of nitroarenes with ethanol
Farhadi, Saeid,Kazem, Maryam,Siadatnasab, Firouzeh
, p. 606 - 613 (2011/04/16)
NiO nanoparticles with an average size of 12 nm and a high specific surface area of 88.5 m2/g were easily prepared via the thermal decomposition of the complex Ni(dmgH)2 and were characterized by TGA, XRD, FT-IR, TEM and BET surface area measurement. This nanosized transition metal oxide was used as a new heterogeneous catalyst for the reduction of nitroarenes under microwave irradiation. The efficient and selective reduction of aromatic nitro compounds into their corresponding amines was observed by using ethanol as a hydrogen donor (reducing agent) and KOH as a promoter under microwave irradiation. This highly regio-and chemoselective method is fast, simple, inexpensive, high yielding, clean and compatible with several sensitive functionalities, such as halogens,-OH,-OCH3,-CHO,-COCH 3,-COOH,-COOEt,-CONH2,-CN,-CHCH2 and-NHCOCH3. This method is suitable for the large scale preparation of different substituted anilines as well as other arylamines. In addition, the catalytic activity of nanosized NiO is higher than that of the bulk sample.
Preparation and thermal behaviour of divalent transition metal complexes of pyromellitic acid with hydrazine
Vairam,Premkumar,Govindarajan
, p. 979 - 985 (2011/01/10)
Hydrazine forms two different types of complexes with divalent metal ions and pyromellitic acid (H4pml) in aqueous medium: (i) hydrazinium complexes of formulae, (N2H5)2M(pml) ?xH2O, where x = 3 for M=Ni and x = 4 for M=Co or Zn, and (N2H5)2Mn(H2pml)2, at pH 4.5, (ii) neutral hydrazine complexes with formulae, M2(pml)(N 2H4) n ?xH2O where M=Co or Ni when n = 4 and x = 5 or 4 and M=Zn or Cd when n = 2, and x = 4 or 3 at pH 7, and M(H2pml)(N2H4)?xH2O where x = 4; M=Cu and x = 0; M=Hg, at pH 3, 7.5, respectively. All the complexes are insoluble in water, alcohol and ether. The N-N stretching frequency (990-1,007 cm-1 for coordinated hydrazinium ion and 956-985 cm-1 for bridged neutral hydrazine) indicates the nature of hydrazine present in the complexes. Simultaneously TG-DTA analysis indicates that hydrazinium complexes undergo dehydration and dehydrazination in a single step endothermally in the range of 289-300 °C whereas neutral hydrazine complexes undergo endothermic dehydration (~100 °C) followed by exothermic dehydrazination in the temperature range, 253-332 °C. The anhydrous metal carboxylates further decompose exothermally to leave the respective metal oxides or metal carbonates except zinc, which gives its oxalate as the end product. X-ray powder patterns indicate that even the complexes with the same formulation possess no isomorphism.
Thermal decomposition of energetic materials. 34. Decarbonylation, decarboxylation, and coupling reactions of metal propiolates, M[O2CC≡CH]
Stoner Jr.,Brill
, p. 4500 - 4506 (2008/10/08)
The thermal decomposition of metal propiolate salts, M[O2CC≡CH]x·y[HO 2CC≡CH]·zH2O, where M = Na (x = 1, y = 0, z = 0), K (x = 1, y = 0, z = 0), Rb (x = 1, y = 0.5, z = 0), Co (x = 2, y = 0, z = 3), Ni (x = 2, y = 0, z = 0), and Zn (x = 2, y = 0, z = 2), is described for slow heating by TGA, DSC, and IR spectroscopy and for fast heating (80-300°C/s) by FTIR/temperature profiling. The decomposition temperatures and ΔHdec of the Na+, K+, and Rb+ salts predict their tendency to thermalize by decarbonylation, decarboxylation, or coupling when in the unconfined state. Decarbonylation yields M2CO3, CO, C, and C2H2, while decarboxylation yields M2CO3, CO2, C, and C2H2. Coupling leads to a solid product resembling an acetylenedicarboxylate salt. The CO/CO2 and C2H2/COx gas product ratios for these salts support these descriptions. A lower decomposition temperature, lower lattice energy, and smaller ΔH of decomposition favors decarboxylation and coupled products (Rb+), while the reverse favors decarbonylation (Na+, K+). Extensions of these notions to the Co2+, Ni2+, and Zn2+ salts indicate that the decomposition temperature reliably predicts their tendency to decarbonylate and form a carbonate (Ni2+), or decarboxylate and form coupled products (Co2+, Zn2+). All six salts give evidence of coupling when slowly thermalized between two BaF2 plates.
OPTICAL, X-RAY K-ABSORPTION AND THERMAL STUDIES ON SOME METAL-CHELATES OF SALICYLHYDRAZIDE
Khadikar, Padmakar V.,Apte, Dhanashri,Amma, Bhagirathi,Ali, Syed M.
, p. 169 - 186 (2007/10/02)
The metal chelates of VO(II), Cu(II), Ni(II), Co(II) and Zn(II) with salicylhydrazide (SH) have been synthesized and characterized by elemental, I.R., Optical, X-ray K-absorption and magnetochemical studies.Thermal behaviour (TG, DTG and DTA) of the chelates has also been investigated and the thermal degradation products have been identified by X-ray K-absorption as well as far-I.R. spectra.The former study indicated change from octahedral to tetrahedral stereochemistry as a consequence of dehydration.The thermal stability of the complexes follows the order: VO(II)>Cu(II)>Co(II)>Ni(II)>Zn(II).This is roughly in the order of the binding strength of water molecules to the metal ion.
Carbonylnickelates. 3. Synthesis and chemical characterization of the [Ni12(CO)21H4-n]n- (n = 2, 3, 4) clusters
Ceriotti, Alessandro,Chini, Paolo,Della Pergola, Roberto,Longoni, Giuliano
, p. 1595 - 1598 (2008/10/08)
The hydrolysis of the [Ni6(CO)12]2- dianion under buffered conditions results in the synthesis of the interstitial hydride derivatives [Ni12(CO)21H2]2- and [Ni12(CO)21H]3-. The two compounds are related by an easily reversible protonation-deprotonation equilibrium. In contrast, deprotonation of [Ni12(CO)21H]3- to the corresponding [Ni12(CO)21]4- tetraanion is possible only under severe conditions. The tetraanion has been obtained as a byproduct of the synthesis of [Ni6(CO)12]2- by reduction of Ni(CO)4 in KOH-saturated methanolic solution. The [Ni12(CO)21H4-n]n- (n = 2, 3, 4) derivatives have been isolated in pure crystalline form with a variety of tetrasubstituted ammonium or phosphonium cations. All these dodecanuclear nickel carbonyl clusters are rapidly degraded by carbon monoxide (25°C, 1 atm) and possess limited thermal stability. Degradation of [Ni12(CO)21H2]2- by carbon monoxide in THF solution affords the binuclear hydride derivative [Ni2(CO)6H]- and Ni(CO)4. Degradation of [Ni12(CO)21H]3-, in addition to the former products, gives rise to [Ni5(CO)12]2-, which becomes the only product, together with Ni(CO)4, when starting from [Ni12(CO)21]4-.
