13965-03-2Relevant articles and documents
ELECTROCHEMICAL BEHAVIOUR OF Pd(0) AND Pd(II) COMPLEXES WITH TRIPHENYLPHOSPHINE IN DIMETHYLFORMAMIDE.
Vasini, E. J.,Giordano, M. C.
, p. 205 - 212 (1988)
The electrochemical behaviour of a palladium electrode in the presence of ligands such as chloride ions and triphenylphosphine (PPh//3) in dimethylformamide (DMF) solution, and that of a DMF solution of palladium chloride in the presence of the same ligands were investigated by cyclic voltammetry and chronopotentiometric techniques. The PdCl//2-ligands solution systems form a well-defined redox couple at high ( greater than 4) PPh//3 to Cl** minus concentration ratio. The redox couple corresponds to a quasi-reversible surface process, whereas the anodic dissolution of Pd in the presence of ligands is better described as a catalytic reaction with an irreversible charge transfer.
Influences of the electronic and steric effects of the substituents in cyclopalladation of ferrocenylhydrazones
Lopez, Conception,Granell, Jaume
, p. 211 - 225 (1998)
The syntheses and characterization of seven novel ferrocenylhydrazones of general formulae: [(η5-C5H5)Fe{(η5-C 5H4)-CH=N-NH(R)}] {with R = C6H4-4-Cl (1a), C6H4-4-NO2 (1b), C6H5 (1c), C6H3-2,4-(NO2)2 (1d), C6H3-2,5-(Cl)2 (1e), C6F5 (1f) or C6H4-2-CH3 (1g)} are reported. We also describe the reactions of compounds 1 with PdCl2 in refluxing ethanol, by which different cyclopalladated complexes containing σ(Csp2, aryl-Pd), σ(Csp2, ferrocene-Pd) or σ(Csp3-Pd) bonds were obtained. A comparative study of the ease by which a σ(Csp2, ferrocene-H) or a σ(Csp2, aryl-H) bond in compounds 1 and in the ferrocenylhydrazones: [(η5-C5H5)Fe{(η5-C 5H4)-C(CH3)=N-NH(R)}] (1′) {derived from acetylferrocene} were to be activated is also reported.
Metal coordination mediated reversible conversion between linear and cross-linked supramolecular polymers
Wang, Feng,Zhang, Jinqiang,Ding, Xia,Dong, Shengyi,Liu, Ming,Zheng, Bo,Li, Shijun,Wu, Ling,Yu, Yihua,Gibson, Harry W.,Huang, Feihe
, p. 1090 - 1094 (2010)
(Figure Presented) The dynamic duo: Different topologies of dynamic supramolecular polymers, such as linear (see picture, left) and crosslinked species (right), can be reversibly interconverted by external stimuli that utilize host-guest and metal-ligand
Regioselectivity in the Sonogashira coupling of 4,6-dichloro-2-pyrone
Fairlamb, Ian J. S.,O'Brien, Ciara T.,Lin, Zhenyang,Lam, King Chung
, p. 1213 - 1216 (2006)
The Sonogashira cross-coupling of 4,6-dichloro-2-pyrone with terminal acetylenes proceeds in good yields and high regioselectivity for the 6-position; dibenzylidene acetone (dba) type ligands play a non-innocent role in reactions mediated by Pd(dba)2/PPh3; theoretical studies indicate that C-6 oxidative addition is favoured both kinetically and thermodynamically.
Dinuclear PdII/PtIIcomplexes [M2(phosphine)n(thio-ligand)3]Cl incorporating N,S-bridged pyridine-2-thiolate and benzimidazoline-2-thiolate
Lobana, Tarlok S.,Sandhu, Amanpreet K.,Mahajan, Rakesh K.,Hundal, Geeta,Gupta, Sushil K.,Butcher, Ray J.,Castineiras, Alfonso
, p. 25 - 35 (2017)
Equimolar reaction of [PdCl2(dppm)] {dppm?=?bis(diphenylphosphino) methane} with pyridine-2-thione (pySH) in presence of NaOH base in aqueous ethanol formed dinuclear mixed-ligand complex, [PdII2(μ-κ2:N,S-pyS)3(μ-P,P-dppm)]Cl 1. Similarly, reaction of PdCl2(PPh3)2with benzimidazoline-2-thione (bzimSH) in 1:2?M ratio in the presence of Et3N base in acetonitrile has formed a dinuclear complex, [PdII2(μ-κ2:N,S-bzimS)2(κ1-S-bzimS)(PPh3)3]Cl·2H2O 2. Surprisingly, analogous thio-ligand, 1,3-imidazoline-2-thione (imzSH), merely formed a simple square planar complex, [Pd(κ1-S-imzSH)4]Cl2·2H2O 3. The reaction of H2PtCl6with pySH and dppm (1:1:1?M ratio) in the presence of Et3N base in toluene–ethanol (1:1:: v/v) mixture also formed a mixed-ligand dinuclear complex [PtII2(μ-κ2:N,S-pyS)3(μ-P,P-dppm)]Cl similar to 1. All these complexes have been characterized using analytical data, IR, NMR (1H,31P), UV–vis, fluorescence, ESI-mass and single crystal X-ray crystallographic techniques. The anionic thio-ligands are N,S-bridged in complexes 1 and 4, both N,S-bridged and κ1-S bonded in 2 and as neutral κ1-S bonded in 3. There are short M?M contacts in 1 and 4 (1: 2.7249(5) ? 4: 2.7350(8) ?). Complexes 1, 3 and 4 showed intense fluorescence. ESI mass spectral studies of 1, 3 and 4 revealed the formation of molecular ions and other species.
Quasi-homogeneous catalytic conversion of CO2into quinazolinones inside a metal-organic framework microreactor
Cheng, Peng,Gao, Jianbo,Ma, Jian-Gong,Zhou, Zhenzhen
, p. 5456 - 5460 (2021)
Management of CO2 has been attracting great attention in this century. Reaction of CO2 with 2-haloanilines and isocyanides is an attractive way for both converting CO2 and producing quinazolinones, which are key intermediates for the synthesis of various biologically active products. However, the heterogeneous and relatively inert nature of CO2 with 2-haloaniline and isocyanide reactants limits the types of suitable catalysts. Herein, we use metal-organic frameworks (MOFs) as a microreactor , in which Pd(PPh3)2Cl2 is well-dispersed as a single-molecular catalyst, and the reactants react in the molecular level through a quasi-homogeneous way to convert CO2 into quinazolinones under mild conditions with both promising yields over homogeneous catalysts and good recyclability as a heterogeneous reaction. The MOF-assisted single-molecular catalysis strategy should contribute to CO2 conversion, production of quinazolinone-type bioactive intermediates, and the epochal development of homo-and-heterogeneous catalysis. This journal is
Schiff base triphenylphosphine palladium (II) complexes: Synthesis, structural elucidation, electrochemical and biological evaluation
Shabbir, Muhammad,Akhter, Zareen,Ahmad, Iqbal,Ahmed, Safeer,Shafiq, Maryam,Mirza, Bushra,McKee, Vickie,Munawar, Khurram Shahzad,Ashraf, Ahmad Raza
, p. 250 - 258 (2016)
The complexes N-(2-oxidophenyl)salicylideneiminatotriphenylphosphine palladium(II) (1) and N-(2-sulfidophenyl)salicylideneiminato triphenylphosphine palladium(II) (2) of tridentate Schiff bases derived from salicylaldehyde and an amino- or thiophenol, have been synthesized and characterized by various spectroscopic, analytical and electro-analytical techniques. X-ray single crystal analysis of complex 1 has revealed its square planar geometry. The thermal analysis has shown the absence of coordinated water and final degradation product is PdO. The alkaline phosphatase studies have indicated that enzymatic activity is concentration dependent which is inversely proportional to the concentration of the compounds. The biological assays (brine shrimp cytotoxicity, DPPH) have reflected their biologically active and mild antioxidant nature. However, results of DNA protection assay have shown that they possess moderate protective activity against hydroxyl free radicals (OH). The voltammetric studies ascertain two-electron reduction of the compounds through purely diffusion controlled process and reveal intercalative mode of drug DNA interactions.
Reactivity of [PdCl(bdtp)](BF4) with monodentate neutral and anionic ligands. Structure of [Pd(bdtp)(PPh3)](BF4)2 (bdtp = 1,5-bis(3,5-dimethyl-1-pyrazolyl)-3-thiapentane)
de León, Antonio,Pons, Josefina,García-Antón, Jordi,Solans, Xavier,Font-Bardía, Mercè,Ros, Josep
, p. 3801 - 3806 (2009)
Complex [PdCl(bdtp)](BF4), in presence of AgBF4 or NaBF4, reacts with pyridine (py), triphenylphosphine (PPh3), cyanide (CN-), thiocyanate (SCN-) or azide (N3-) ligand
Interaction of palladium(II) complexes with amino-alcohols: Synthesis of new amino-carbonyl complexes, key intermediates to cyclic carbamates
Giannoccaro, Potenzo,Dibenedetto, Angela,Gargano, Michele,Quaranta, Eugenio,Aresta, Michele
, p. 967 - 975 (2008)
The interaction between carbon monoxide and aromatic or aliphatic amino-alcohols promoted by some palladium(II) tetracoordinated complexes, stabilized by aryl mono- and diphosphines [triphenylphosphine (PPh3); 1,2-bis(diphenylphosphine)ethane (dppe)], an amino-phosphine [(2-(/3-diphenylphosphino)ethylpyridine) (PN)], and diamines [2,2′-dipyridine (dipy); 1,10-phenanthroline (phen)], was investigated. All tested complexes and substrates were shown to interact with CO to afford either stable carbamoyl complexes, which were isolated and studied for their reactivity, or, directly, organic products. From the reaction of PdCl 2(PN) with 4-aminophenol (4-APhOH, a) the stable carbamoyl complex (PN)PdCl(CONHC6H4-OH), able to release the amino-carbonyl ligand as isocyanate HOC6H4NCO, was isolated. The aliphatic amino-alcohols H2N-R-OH [2-aminoethanol (2-AE, b); 1-amino-2-propanol (1-A2P, c); 3-aminopropanol (3-AP, d); 2-aminobutanol (2-A1B, e); 4-aminobutanol (4-AB, f); 5-aminopentanol (5-APE, g); 6-aminohexanol (6-AHX, h)] were reacted with all Pd complexes described above, but only when the triphenylphosphine ligand was used was it possible to isolate the stable carbamoyl complexes (PPh3)2PdCl(CONH-R-OH). The Pd(II) complexes with other ligands reacted in the same way, but the relevant intermediate complexes decomposed during the progress of the reaction, giving a mixture of cyclic carbamates and ureas and the relevant Pd(0) complex, "Pd-L" (L = PN, dppe, dipy, phen), which converted into Pd-black and the free ligand. Carbamoyl complexes with an aliphatic amino-alcohol bearing a primary amine are unprecedented in the literature. They were characterized by means of IR and NMR spectroscopy and studied for their reactivity. All the complexes upon simple heating or by reaction with I2 or CuCl 2 release the amino-carbonyl function as cyclic carbamate and/or urea, depending on the complex and the presence or absence of the free amino-alcohol in solution.
Palladium catalyzed hydrodechlorination of α-chloroacetophenones by hydrogen transfer from the H2O-CO system
Cavinato,Pasqualetto,Ronchin,Toniolo
, p. 15 - 22 (1997)
PdCl2(PPh3)2, in combination with an extra amount of PPh3, is an excellent catalyst precursor for the hydrodechlorination of α-chloroacetophenone to acetophenone by hydrogen transfer from the H2O-CO system. The reaction occurs with concomitant evolution of CO2. Under typical reaction conditions (50-70°C, 40-80 atm, substrate/Pd/P = 2000/1/50, H2O/substrate = 8-12/1), the reaction occurs in 70-80% yield in 2 h, using ethanol or dioxane as a solvent ([Pd] = 5.10-4 mol · l-1). When the catalyst precursor is employed without adding an additional amount of PPh3 extensive decomposition to metallic palladium occurs. Also Pd/C is active in promoting the hydrodechlorination reaction. As expected the reaction rate increases upon increasing concentration of catalyst, carbon monoxide pressure and temperature. The yield is slightly influenced by the concentration of the substrate. The effect of the concentration of H2O is the most significant. In ethanol as a solvent at low concentration of water the reaction rate increases to reach a plateau above 6-7 10-2 mol · l-1 of water. On the basis of the fact that it is known that (i) the precursor is reduced to a Pd(0) species by the H2O-CO system, even in the presence of hydrochloric acid, which is freed during the course of the hydrodechlorination reaction and that (ii) the starting α-chloroacetophenone oxidatively adds to Pd(0) to give Pd(CH2COPh)Cl(PPh3)2 (I) and that (iii) this complex reacts with hydrochloric acid to give acetophenone and PdC12(PPh3)2 (II), it is proposed thai the hydrodechlorination reaction proceeds via the intermediacy of a species analogous to complex (I) and that (II) is reduced to the Pd(0) complex through the intercation of CO and H2O with the metal center to give a species having a Pd-(COOH) moiety, which after β-hydride abstraction gives a palladium-hydride species with concomitant evolution of CO2. The hydride gives off a proton and reduces Pd(II) returning a Pd(0) species back to the catalytic cycle. We found also that complex (I) is reduced to a Pd(0) complex with formation of acetophenone through the action of H2O and CO. It is proposed that this reaction, which may be at the base of a different catalytic path, occurs via the intermediacy of a species having a H-Pd-(CH2COPh) which, after reductive elimination of acetophenone give the Pd(0) complex starting a new catalytic cycle. In the case of the Pd/C catalyzed hydrodechlorination it is suggested that H2O and CO interacts on the surface of the metal to give a hydride and evolution of CO2 and that this hydride displaces a chloride anion from α-chloroacetophenone absorbed on the catalytic surface to give the hydrodechlorination product.
