23523-32-2Relevant articles and documents
Synthetic access to a phosphorescent non-palindromic pincer complex of palladium by a double oxidative addition-comproportionation sequence
Feuerstein, Wolfram,Breher, Frank
supporting information, p. 12589 - 12592 (2020/11/02)
A highly luminescent non-palindromic [(C^C^N)Pd] pincer complex forms upon reacting pyridine-substituted 2,2′-diiodo-biphenyl with [Pd(PPh3)4]. This case study establishes for the first time that the title compound is formed via a double oxidative addition-comproportionation sequence. DFT and TDDFT calculations complement mechanistic and photophysical characterizations.
Mono- and dinuclear palladium(II) complexes incorporating 1,2,3-triazole-derived mesoionic carbenes: syntheses, solid-state structures and catalytic applications
Zhang, Xin,Yan, Xuechao,Zhang, Bo,Wang, Ran,Guo, Shuai,Peng, Shiyong
, p. 39 - 48 (2018/08/06)
Two 1,2,3-triazole-derived monocationic salts 3 and 4 bearing N-aryl wingtips were prepared using copper-catalyzed “click” reactions followed by alkylations with iodomethane. Employing a silver–carbene transfer method, two dinuclear palladium(II) complexes of triazolin-5-ylidenes (5/6) were obtained, the former of which has been reported previously. Bridge-cleavage reaction of 5 as a representative with PPh3 yielded cis-configured mesoionic carbene/phosphine hybrid complex cis-7 and homoleptic bis(phosphine) complex 8, suggesting the presence of a ligand exchange process. In contrast, bridge breakages of 5/6 with pyridine cleanly afforded PEPPSI-type complexes 9 and 10 in near quantitative yields. Finally, all complexes were exploited to catalyze Mizoroki–Heck coupling reactions with aryl bromides as the substrates, and PEPPSI-type complex 9 was found to be the best performer generally giving good to excellent yields.
Catalytic Chemoselective and Stereoselective Semihydrogenation of Alkynes to E-Alkenes Using the Combination of Pd Catalyst and ZnI2
Maazaoui, Radhouan,Abderrahim, Raoudha,Chemla, Fabrice,Ferreira, Franck,Perez-Luna, Alejandro,Jackowski, Olivier
supporting information, p. 7544 - 7549 (2019/01/03)
An efficient E-selective semihydrogenation of internal alkynes was developed under low dihydrogen pressure and low reaction temperature from commercially available reagents: Cl2Pd(PPh3)2, Zn0, and ZnI2. Kinetic studies and control experiments underline the significant role of ZnI2 in this process under H2 atmosphere, establishing that the transformation involves syn-hydrogenation followed by isomerization. This simple and easy-to-handle system provides a route to E-alkenes under mild conditions.
Nuances in Fundamental Suzuki-Miyaura Cross-Couplings Employing [Pd(PPh3)4]: Poor Reactivity of Aryl Iodides at Lower Temperatures
Ho, Curtis C.,Olding, Angus,Smith, Jason A.,Bissember, Alex C.
, p. 1745 - 1750 (2018/06/18)
We have explored fundamental Pd-catalyzed Csp2-Csp2 Suzuki-Miyaura cross-couplings of aryl iodides (Ar-I) employing "classical" Pd/PPh3 catalyst systems. Surprisingly, we observed particularly inefficient couplings of these ostensibly reactive electrophiles in a range of conventional solvent mixtures at lower temperatures (50 °C), which was in stark contrast to analogous reactions featuring the equivalent aryl bromides. This feature of well-established Pd/PPh3-mediated Suzuki-Miyaura reactions has received scant attention in the literature. Most significantly, our studies suggest that the inefficient coupling of aryl iodides at lower temperatures derives from the unexpectedly poor turnover of the key on-cycle intermediate trans-[Pd(PPh3)2(Ar)(I)] (or related PdII-I species) in the presence of PPh3.
Oxidative Mechanochemistry: Direct, Room-Temperature, Solvent-Free Conversion of Palladium and Gold Metals into Soluble Salts and Coordination Complexes
Do, Jean-Louis,Tan, Davin,Fri??i?, Tomislav
supporting information, p. 2667 - 2671 (2018/02/06)
Noble metals are valued, critical elements whose chemical activation or recycling is challenging, and traditionally requires high temperatures, strong acids or bases, or aggressive complexation agents. By using elementary palladium and gold, demonstrated here is the use of mechanochemistry for noble-metal activation and recycling by mild, clean, solvent-free, and room-temperature chemistry. The process leads to direct, efficient, one-pot conversion of the metals, including spent catalysts, into either simple water-soluble salts or metal–organic catalysts.
Synthesis, Characterization, and Reactivity of Palladium Fluoroenolate Complexes
Arlow, Sophie I.,Hartwig, John F.
supporting information, p. 16088 - 16091 (2017/11/22)
Cross-coupling reactions of aryl groups with α-fluoro carbonyl compounds catalyzed by palladium complexes have been reported, but palladium fluoroenolate intermediates relevant to such reactions have not been isolated or even detected previously. We report the synthesis, structural characterization, and reactivity of a series of C-bound arylpalladium fluoroenolate complexes ligated by monophosphines and bisphosphines. DPPF-ligated arylpalladium fluoroenolate complexes (DPPF = 1,1-bis(diphenylphosphino)-ferrocene) derived from a monofluoroester, a difluoroester, difluoroamides, and difluoroacetonitrile underwent reductive elimination in high yields. Reductive elimination was faster from complexes containing less electron-withdrawing fluoroenolate groups and longer Pd-C(enolate) bonds than from complexes containing more electron-withdrawing fluoroenolate groups and shorter Pd-C(enolate) bonds. The rates of reductive elimination from these C-bound fluoroenolate complexes were significantly faster than those of the analogous trifluoromethyl complexes.
Improved synthesis method of palladium complex
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Paragraph 0006, (2017/06/02)
The invention discloses an improved synthesis method of a palladium complex (X in a general formula is equal to Br or I) and belongs to the field of organic chemistry. The improved synthesis method is characterized by including: using PdCl2(PPh3)2 and sodium iodide or sodium bromide as raw materials, wherein a feeding molar ratio is 1:10; using dichloromethane and water as solvents according to a volume ratio of 1:1, reacting to obtain a product, and subjecting the product to extracting, washing and filtering to obtain high-quality PdX2(PPh3) palladium complex. The palladium complex is high in yield, the method is simpler, the raw materials are cheaper, and the method has good industrial application prospect.
σ-bond metathesis between M-X and RC(O)X′ (M = Pt, Pd; X, X′ = Cl, Br, I): Facile determination of the relative Δ G values of the oxidative additions of RC(O)X to an M(0) complex, evidence by density functional theory calculations, and synthetic applications
Kuniyasu, Hitoshi,Sanagawa, Atsushi,Nakane, Daisuke,Iwasaki, Takanori,Kambe, Nobuaki,Bobuatong, Karan,Lu, Yunpeng,Ehara, Masahiro
supporting information, p. 2026 - 2032 (2013/05/09)
The novel utility of the ligand exchange reaction between M-X and RC(O)X′ (X, X′ = halogen; R = aryl, alkyl) is described. The relative ΔGs (ΔΔGs) of the oxidative additions of acid halides RC(O)X to M(PPh3)2Ln (M = Pt, Pd) were determined using the halogen-exchange reactions between X of trans-M(X)[C(O)R](PPh3)2 and X′ of RC(O)X′. Experimental thermodynamics data are reasonably consistent with those obtained by density functional theory (DFT) calculations. Activation parameters obtained by experiments as well as a systematic DFT study supported the fact that reactions occurred through slightly distorted quadrangular pentacoordinated σ-bond metatheses, in which the Cl atom underwent a more indirect course than the Br atom. Moreover, exchange reactions were employed as the accessible prototype for the conversion of halogen ligands of nickel triad complexes into heavier halogen ligands.
Atomic contributions from spin-orbit coupling to 29Si NMR chemical shifts in metallasilatrane complexes
Autschbach, Jochen,Sutter, Kiplangat,Truflandier, Lionel A.,Brendler, Erica,Wagler, Joerg
supporting information, p. 12803 - 12813 (2012/11/07)
New members of a novel class of metallasilatrane complexes [X-Si-(μ-mt)4-M-Y], with M=Ni, Pd, Pt, X=F, Cl, Y=Cl, Br, I, and mt=2-mercapto-1-methylimidazolide, have been synthesized and characterized structurally by X-ray diffraction and by 29Si solid-state NMR. Spin-orbit (SO) effects on the 29Si chemical shifts induced by the metal, by the sulfur atoms in the ligand, and by heavy halide ligands Y=Cl, Br, I were investigated with the help of relativistic density functional calculations. Operators used in the calculations were constructed such that SO coupling can selectively be switched off for certain atoms. The unexpectedly large SO effects on the 29Si shielding in the Ni complex with X=Y=Cl reported recently originate directly from the Ni atom, not from other moderately heavy atoms in the complex. With respect to Pd, SO effects are amplified for Ni owing to its smaller ligand-field splitting, despite the smaller nuclear charge. In the X=Cl, Y=Cl, Br, I series of complexes the Y ligand strongly modulates the 29Si shift by amplifying or suppressing the metal SO effects. The pronounced delocalization of the partially covalent M←Y bond plays an important role in modulating the 29Si shielding. We also demonstrate an influence from the X ligand on the 29Si SO shielding contributions originating at Y. The NMR spectra for [X-Si-(μ-mt) 4-M-Y] must be interpreted mainly based on electronic and relativistic effects, rather than structural differences between the complexes. The results highlight the sometimes unintuitive role of SO coupling in NMR spectra of complexes containing heavy atoms. All in a spin! The class of metallasilatrane complexes [X-Si-(μ-mt)4-M-Y] with M=Ni, Pd, and Pt, previously reported for X=Y=Cl (shown here), has been extended by new members with X=F and Y=Br and I. New synthetic routes, structural characterizations by X-ray diffraction, and 29Si solid-state NMR data are reported. Spin-orbit effects on the 29Si chemical shifts were investigated with the help of relativistic density functional calculations. Copyright
1,3-Diphosphorus ylide cyclopentadienylium salts: Synthesis, structures, and application in coupling reactions
Xu, Chen,Wang, Zhi-Qiang,Li, Zhen,Wang, Wei-Zhou,Hao, Xin-Qi,Fu, Wei-Jun,Gong, Jun-Fang,Ji, Bao-Ming,Song, Mao-Ping
, p. 798 - 801 (2012/05/04)
The 1,3-diphosphorus ylide cyclopentadienylium salts (C5H 3)(PPh3)2I (1) and (C5H 3)[P(4-CH3-Ph)3]2I (2) have been prepared from the reaction of 1,1′-dichloromercurioferrocene with Pd(PPh3)4 and with Pd[P(4-CH3-Ph) 3]4, respectively. The molecular structure of 1 has been determined by X-ray diffraction analyses. The Pd(OAc)2/1 or 2/K tOBu system is highly efficient for the coupling reactions of aryl chlorides at room temperature.
