16483-18-4Relevant academic research and scientific papers
Fast Reactions at Planar Four-co-ordinate Complexes. Part 4. The Reaction of Chelate Dichloropalladium(II) Complexes with Some Bidentate Ligands
Cusumano, Matteo,Guglielmo, Giovanni,Ricevuto, Vittorio
, p. 1722 - 1725 (1981)
The reaction between the square-planar complexes and ethylenediamine proceeds in two consecutive stages yielding Cl2 as a final product.The intermediate species is Cl2 or when L-L is 1,2-bis(phenylthio)ethane.The rate of replacement of the first chloride co-ordinated to palladium(II) in the substrates at 25 deg C in dimethylformamide is strongly dependent on the nature of the ligand L-L, covering four orders of magnitude.The reaction between the substrates (M = Pd or Pt, bipy = 2,2'-bipyridine) and the bidentate nucleophiles ethylenediamine and dithio-oxamide proceeds according to an analogous two-stage reaction scheme when M is palladium; in the platinum derivatives, however, the chelate bipyridine is inert towards substitution.In the solvent dimethylformamide the entering group ethylenediamine behaves as a very effective nucleophile.
Zeolite-Encaged Pd–Mn Nanocatalysts for CO2 Hydrogenation and Formic Acid Dehydrogenation
Asakura, Hiroyuki,Chang, Albert,Chen, Benjamin W. J.,Hülsey, Max J.,He, Qian,Sun, Qiming,Tanaka, Tsunehiro,Wang, Chi-Hwa,Wang, Ning,Yan, Ning,Yang, Chia-Min,Yu, Jihong
, p. 20183 - 20191 (2020)
A CO2-mediated hydrogen storage energy cycle is a promising way to implement a hydrogen economy, but the exploration of efficient catalysts to achieve this process remains challenging. Herein, sub-nanometer Pd–Mn clusters were encaged within silicalite-1 (S-1) zeolites by a ligand-protected method under direct hydrothermal conditions. The obtained zeolite-encaged metallic nanocatalysts exhibited extraordinary catalytic activity and durability in both CO2 hydrogenation into formate and formic acid (FA) dehydrogenation back to CO2 and hydrogen. Thanks to the formation of ultrasmall metal clusters and the synergic effect of bimetallic components, the PdMn0.6?S-1 catalyst afforded a formate generation rate of 2151 molformate molPd?1 h?1 at 353 K, and an initial turnover frequency of 6860 mol (Formula presented.) molPd?1 h?1 for CO-free FA decomposition at 333 K without any additive. Both values represent the top levels among state-of-the-art heterogeneous catalysts under similar conditions. This work demonstrates that zeolite-encaged metallic catalysts hold great promise to realize CO2-mediated hydrogen energy cycles in the future that feature fast charge and release kinetics.
Effect of charge and surface area on the cytotoxicity of cationic metallointercalation reagents
Edwards, Gavin L.,Black, David St.C.,Deacon, Glen B.,Wakelin, Laurence P.G.
, p. 969 - 979 (2007/10/03)
Reaction of a series of nitrogen donor ligands (1-phenylpyrazoles, 2-phenylpyridine, benzo[h]quinoline, 1-(2′-pyridyl)indole, 1-phenylindazole, and 2-phenylindazole) with palladium(II) and platinum(II) salts gave complexes where ortho-metallation had occurred resulting in bidentate binding to the metal centres through N and C atoms. These cyclometallated products were isolated as μ-chloro dimers. Subsequent treatment of these μ-chloro dimers with chelating diamines such as 1,2-ethanediamine converted them into 14 cationic (1+) complexes. Analogous coordination mixed ligand complexes (charge 2+) were prepared by reaction of dichloro(1,2-ethanediamine-N, N′)palladium(II) with aromatic diamines such as 2-(1′-pyrazolyl) pyridine, 2,2′-bipyridine, and 1,10-phenanthroline. The complexes exhibited growth inhibitory activity against L1210 mouse leukaemia cells in vitro over a wide concentration range; in general, the cyclometallated complexes were more active than the mixed ligand complexes, although one cyclometallated organoplatinum complex was less active than the mixed ligand analogue. Substitution around the periphery of the aromatic ligands also resulted in increased activity. One complex, derived from 1-(2′-pyridyl) indole, was tested in vivo and showed no significant antitumour inhibition against P388 leukaemia at doses below toxic levels.
Synthesis and structural elucidation of heterobimetallic complexes comprising palladium(II) and a group fourteen element
Sharma, Kripa,Fahmi, Nighat,Singh
, p. 1291 - 1293 (2007/10/03)
Synthesis and structural elucidation of some new heterobimetallic complexes of the type [Pd(C2H6N2)2M2R)4]Cl2 and [Pd(C3H8N2)2M2(R)4]Cl2 are described. These chelates were prepared by treating monometallic derivatives, viz., [Pd(C2H6N2) 2Cl2 and [Pd(C3H10N2)]Cl2 with Group 14 organo-metallic chlorides, Ph2MCl2, Me2MCl2 or Cp2M1Cl2 (M=Si or Sn and M1=Ti or Zr). The complexes were characterized by elemental analysis, molecular weight determinations and magnetic measurements. Based on infrared, 1H NMR and electronic spectral studies a square-planar geometry around palladium(Il) has been proposed for all the derivatives. Conductivity measurements indicate the ionic nature of all the complexes.
Fast Reactions at Planar Four-co-ordinate Complexes. Part 5. The Solvent Effect on the Leaving Group in the Reactions of Neutral and Cationic Palladium(II) Complexes
Cusumano, Matteo,Giannetto, Antonio,Guglielmo,Giovanni,Ricevuto, Vittorio
, p. 2445 - 2448 (2007/10/02)
The rate of replacement of the group X by n-propylamine or thiourea in the substrates NO3 (3-NHpd = 3-azapentane-1,5-diamine; X=Cl, Br, I, N3, SCN, or NO2) and the equilibrium constants of some of these reactions have been studied in the solvents methanol, dimethylformamide, and dimethylsulfoxide at 25 deg C.The kinetics of substitution of the first group X, by ethylenediamine, in the substrates in dimethylformamide and in some cases in methanol, at 25 deg C, have also been followed.Both rate and equilibrium constants vary sensibly on going from protic to dipolar aprotic solvents.The lability sequence of the leaving group depends on the nature of the substrates and in all cases is affected to a large extent by the change in the solvent nature.
