- Synthesis, isolation, and characterization of an organometallic triiodopalladium(IV) complex. quantitative and regioselective synthesis of two C-I reductive elimination products
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Iodine and the pincer complex [Pd(O,N,C-L)I], where L is the monoanionic ligand resulting from deprotonation of the acetyl group of the dimethylmonoketal of 2,6-diacetylpyridine, are in equilibrium at low temperatures with the palladium(IV) complex [Pd(O,N,C-L)I3], which can be isolated at -40 °C and characterized by 1H NMR spectroscopy and X-ray diffraction studies, in spite of its great instability. When the same reaction is carried out at room temperature, a quantitative reductive elimination process occurs, giving L-I, which in the presence of water affords L′-I, resulting from hydrolysis of L-I.
- Vicente, Jose,Arcas, Aurelia,Julia-Hernandez, Francisco,Bautista, Delia
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- Oxidation of palladium with allyl bromide and iodine in dimethylformamide
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The kinetic features of palladium oxidation with allyl bromide and iodine in dimethylformamide were determined. The apparent equilibrium constants, enthalpies, and entropies of reactant adsorption on the palladium surface were calculated.
- Piskunov,Maslennikov,Spirina,Manuilov,Novikov,Maslennikov
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- Enantioselektive Katalyse. VII. Komplexe von (P(R,S),3R,4R,P'(R,S))-3,4-Bis(phenylphosphino)pyrrolidinen. Die Darstellung optisch reiner 1,2-Bisphosphanliganden mit vier Stereozentren, die zusaetzliche funktionelle Gruppen enthalten
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Diastereomeric mixtures of the palladium, the platinum, and the rhodium complexes were prepared from -3,4-bis(phenylphosphino)pyrrolidine (1a).The phosphorus atoms in bis(P(R,S),3R,4R,P'(R,S))-1-(t-butoxycarbonyl)-3,4-bis(phenylphos
- Nagel, Ulrich,Rieger, Bernhard,Bublewitz, Alexander
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- On the Formation of Palladium (II) Iodide Nanoparticles: An In Situ SAXS/XAS Study and Catalytic Evaluation on an Aryl Alkenylation Reaction in Water Medium
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The synthesis of small spherical palladium(II) iodide nanoparticles is reported for the first time. The formation of the particles by ligand exchange, in the presence of poly(vinyl pyrrolidone) in aqueous medium at room temperature, was investigated by in situ time-resolved synchrotron-based SAXS and XANES/EXAFS analysis. These new nanomaterials exhibit a double catalytic role in an aryl alkenylation chemical reaction, working without a base or ligand, in aqueous milieu. There is strong experimental evidence to suggest that the mechanism follows a single-electron transfer (SET) pathway with the participation of iodide as a radical promoter and the palladium atoms as activator of the alkene moiety. This new protocol could evolve into a broadly applicable radical reaction for the functionalization of alkenes.
- Latocheski, Eloah,Marques, Marcelo V.,Albuquerque, Brunno L.,Schuh, Thalia J.,Signori, Aline M.,Oliveira, Daniela C.,Pal, Taransankar,Domingos, Josiel B.
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p. 684 - 688
(2019/01/04)
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- Reactions of Pd-PEPPSI complexes with protic acids
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The Pd-PEPPSI complexes widely used to catalyze numerous reactions eliminate the pyridine ligand on treatment with protic acids to give binuclear complexes [Pd(NHC)X2]2 with the Pd–X–Pd (X = Cl, Br, I) bridging bonds. The reaction proceeds with high yields (78–98%) and can be regarded as a preparative approach to binuclear complexes. A prolonged heat treatment of either Pd-PEPPSI complexes or binuclear [Pd(NHC)X2]2 complexes in the presence of strong protic acids results in the Pd–NHC bond cleavage to give azolium salts (proligands) and palladium salts.
- Chernenko, A. Yu.,Pasyukov,Astakhov,Tafeenko,Chernyshev
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p. 1196 - 1201
(2018/10/15)
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- Regioselective functionalization of iminophosphoranes through Pd-mediated C-H bond activation: C-C and C-X bond formation
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The orthopalladation of iminophosphoranes [R3PN-C 10H7-1] (R3 = Ph31, p-Tol 32, PhMe23, Ph2Me 4, N-C10H 7-1 = 1-naphthyl) has been studied. It occurs regioselectively at the aryl ring bonded to the P atom in 1 and 2, giving endo-[Pd(μ-Cl)(C 6H4-(PPh2N-1-C10H 7)-2)-κ-C,N]2 (5) or endo-[Pd(μ-Cl)(C 6H3-(P(p-Tol)2N-C10H 7-1)-2-Me-5)-κ-C,N]2 (6), while in 3 the 1-naphthyl group is metallated instead, giving exo-[Pd(μ-Cl)(C10H 6-(NPPhMe2)-8)-κ-C,N]2 (7). In the case of 4, orthopalladation at room temperature affords the kinetic exo isomer [Pd(μ-Cl)(C10H6-(NPPh2Me)-8)-κ-C,N] 2 (11exo), while a mixture of 11exo and the thermodynamic endo isomer [Pd(μ-Cl)(C6H4-(PPhMeN-C10H 7-1)-2)-κ-C,N]2 (11endo) is obtained in refluxing toluene. The heating in toluene of the acetate bridge dimer [Pd(μ-OAc)(C 10H6-(NPPh2Me)-8)-κ-C,N]2 (13exo) promotes the facile transformation of the exo isomer into the endo isomer [Pd(μ-OAc)(C6H4-(PPhMeN-C10H 7-1)-2)-κ-C,N]2 (13endo), confirming that the exo isomers are formed under kinetic control. Reactions of the orthometallated complexes have led to functionalized molecules. The stoichiometric reactions of the orthometallated complexes [Pd(μ-Cl)(C10H6- (NPPhMe2)-8)-κ-C,N]2 (7), [Pd(μ-Cl)(C 6H4-(PPh2NPh)-2)]2 (17) and [Pd(μ-Cl)(C6H3-(C(O)NPPh3)-2-OMe-4)] 2 (18) with I2 or with CO results in the synthesis of the ortho-halogenated compounds [PhMe2PN-C10H6-I-8] (19), [I-C6H4-(PPh2NPh)-2] (21) and [Ph 3PNC(O)C6H3-I-2-OMe-5] (23) or the heterocycles [C10H6-(NPPhMe2)-1-(C(O))-8]Cl (20), [C 6H5-(NPPh2-C6H4-C(O)-2] ClO4 (22) and [C6H3-(C(O)-1,2-N-PPh 3)-OMe-4]Cl (24).
- Aguilar, David,Navarro, Rafael,Soler, Tatiana,Urriolabeitia, Esteban P.
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p. 10422 - 10431
(2011/01/05)
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- Ortho palladation and functionalization of L-phenylalanine methyl ester
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The ortho-metalated complex (S,S)-[Pd2{κ2(C,N)- C6H4CH2CH(CO2Me)NH 2-2}2(μ-Br)2] (1b) can be prepared by refluxing in acetonitrile equimolecular amounts of Pd(OAc)2 and L-phenylalanine methyl ester hydrochloride, followed by addition of an excess of NaBr. Complex 1b reacts with 4-picoline to give the mononuclear derivative (S)-[Pd{κ2(CN)-C6H4CH 2CH(CO2Me)NH2-2}2Br(NC 5H4Me-4)] (2), whose crystal structure has been determined by X-ray diffraction. The precursor of 1b, (S,S)- [Pd2{κ2-(C,N)-C6H4CH 2CH(CO2Me)NH2-2}2(μ-Cl) 2] (1a), could not be isolated in a pure form, but it can be used as the starting material for the synthesis of functionalized derivatives of the phenylalanine methyl ester. Thus, CO and RNC (R = Xy, tBu) insert into the Pd-C bond of 1a to afford, after depalladation, (S)-1-oxo-3- (methoxycarbonyl)-1,2,3,4-tetrahydroisoquinoline (3) and (S)-l-R-3- (methoxycarbonyl)-3,4-dihydroisoquinolinium triflate (R = tBu (4), Xy (5)), respectively. Reaction of complex 1b with bromine or iodine affords trans-(S,S)-[PdBr2{NH2CH(CO2Me)CH 2C6H4-X-2}2] (X = Br (6), I (7)), which further reacts with 1, 10-phenanthroline (phen) to give [PdBr 2(phen)] and (S)-2-X-phenylalanine methyl ester (X = Br (8). I (9)).
- Vicente, Jose,Saura-Llamas, Isabel,Garcia-Lopez, Jose-Antonio,Calmuschi-Cula, Beatrice,Bautista, Delia
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p. 2768 - 2776
(2008/10/09)
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- Regiospecific functionalization of pharmaceuticals and other biologically active molecules through cyclopalladated compounds. 2-iodination of phentermine and L-tryptophan methyl ester
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Phentermine hydrochloride ((PhCH2CMe2NH 3)Cl) or L-tryptophan methyl ester hydrochloride ([C 8H6NCH2CH(CO2Me)NH3]Cl) reacts with Pd(OAc)2 in a 1:1 molar ratio to give the cyclometalated complex [Pd2(k2-C,N-C6H4CH 2CMe2NH2-2)2(μ-Cl)2] (1) or (S,S)-[Pd2{K2-C,N-C8H 5NCH2CH(CO2Me)NH2-2} 2(μ-Cl)2] (2), respectively. Reaction of 1 or 2 with iodine affords trans-[PdCl2(NH2CMe2CH 2C6H4I-2)2] (3) or trans-(S,S)-[PdCl2{NH2CH(CO2Me)CH 2C8H5NI-2)2] (4), which further reacts with 1,10-phenanthroline to give [PdCl2(phen)] and the free amine 2-I-phentermine (5) or (S)-2-I-tryptophan methyl ester (6) (overall yields 44 and 51%, respectively, considering phentermine and L-tryptophan methyl ester as starting materials). The crystal structure of complex 3 has been determined by X-ray diffraction studies.
- Vicente, Jose,Saura-Llamas, Isabel,Bautista, Delia
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p. 6001 - 6004
(2008/10/09)
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- Factors influencing linkage isomer preference in palladium(II)-chloranilate complexes
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The actors inluencing linakge isomer preference in the bonding between palladium(II) and the chloranilate dianion (CA2-) are addressed through the synthesis and specctroscopic characterization of 16 compounds where L2 = 2C
- Jeong, Woo-Yeong,Holwerda, Robert A.
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p. 453 - 464
(2007/10/02)
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- Carbonyl complexes of noble metals with halide ligands II. Palladium(II): preparation of Pd2Br4(CO)2 and -: crystal structures of (X=Cl or Br)
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The previously elusive Pd2Br4(CO)2 has been isolated, mixed with PdBr2, from the reaction of PdBr2 with CO under pressure.A centrosymmetric structure is suggested for it on the basis of IR spectral data in solution.Attempts to prepare the corresponding iodo carbonyl complex of palladium(II) failed.The anion - rapidly undergoes decarbonylation both in solution and in the solid state.The stabilities of the halocarbonyl complexes relative to those of the corresponding halides (PdX2 or Pd2X62-) appear to decrease in the sequence Cl > Br > I.The crystal and molecular structures of the - anions (X=Cl, Br) with + as counter-cation have been determined by X-ray diffraction.Crystal data for : monoclinic; space group, P21/n; a 18.231(10); b 8.889(4); c 14.978(8) Angstroem; β 104.88(2) deg; U 2346(2) Angstroem3; Z=4; Dc 1.368 g cm-3; μ(Mo-Kα) 11.29 cm-1; R=0.0397.Crystal data for *C2H2Cl4: triclinic; space group, P/1; a 16.667(10); b 10.376(8); c 9.644(7) Angstroem; α 74.27(3) deg; β 75.12(3) deg; γ 83.27(4) deg; U 1549(2) Angstroem3; Z=2 Dc 1.681 g cm-3; μ(Mo-Kα) 47.84 cm-1; R=0.0886.In both anions, which are essentially planar, the Pd-X bond trans to the CO ligand is not significantly different in length from the other two Pd-X distances.The overall idealized symmetry of the + cation changes from D2d to S4 when the counter-anion is changed from - to -.
- Andreini, Bianca Patrizia,Dell'Amico, Daniela Belli,Calderazzo, Fausto,Venturi, Maria Giovanna,Pelizzi, Giancarlo
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p. 369 - 380
(2007/10/02)
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- The Easy Catalytic Reduction of HClO4, HNO3, and H5IO6 by CO in the Presence of
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The reduction of HCl by CO, catalysed in acetic acid by , is reported together with the parallel formation of either n> or β-PdCl2 according to the reaction conditions.Under similar conditions HNO3 is reduced first to NO2 and then to NO; the known compound *2MeCO2H is the final pruduct.With H5IO6 only insoluble PdI2 is obtained under each reaction condition, corresponding to an easy reduction by CO of H5IO6.
- Ugo, Renato,Chiesa, Anna,Yatsimirski, Anatoli
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p. 1971 - 1974
(2007/10/02)
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