125611-29-2

Upstream product

• 80326-98-3 (2,2-dimethylpropane-1,3-diyl)bis(diphenylphosphane) 
• 131893-90-8 ((C₆H₅)2PCH₂C(CH₃)2CH₂P(C₆H₅)2)PdCl₂ 
• 1364689-16-6 (1,3-bis(diphenylphosphino)-2,2-dimethylpropane)(4-(trifluoeomethyl)phenyl)palladium(II) fluoride 

Relevant academic research and scientific papers

Mechanistic study of the L2Pd-catalyzed reduction of nitrobenzene with CO in methanol: Comparative study between diphosphane and 1,10-phenanthroline complexes

The catalytic activity of PdII compounds supported by 1,10-phenanthroline (phen) or the bidentate diarylphosphane ligand L4X has been studied in the reaction of nitrobenzene with CO in methanol. Both systems are ～70% selective for azoxybenzene and azobenzene but also produce carbonylation products (methyl phenyl carbamate (MPC) and N,N'-diphenylurea (DPU)) and hydrogenation products (aniline and DPU). The PdII(L4X) system also produces methanol oxidation products (dimethyl carbonate, dimethyl oxalate, water). Upon the addition of a catalytic amount of acid, the coupling reaction is suppressed in favor of either the carbonylation reaction (for PdII(phen)) or of both the carbonylation and hydrogenation reaction (for PdII(L4X)). The palladacycle L2PdC(O)N(Ph)OC(O) (C7) and palladium-imido species L2Pd=NPh (C3) were considered as possible carbonylation product-releasing species, where L2 is phen or the diphosphane ligands L4X and L3X. A ligand exchange experiment of phen-C7 with L4X and L3X, ESI-MS analysis of L3X-C7 and phen-C7, and a DFT study of nitrobenzene deoxygenation intermediates to L2Pd=NPh all suggest that C7 is not the major product-releasing intermediate; all data suggest that the barrier for C7 decarbonylation (-CO) is lower than that for decarboxylation (-CO2). C7 is thus thought to be part of an NPh reservoir consisting of palladacycles that are mutually accessible through carbonylation/decarbonylation. Under acidic conditions the decarboxylation barrier is lowered; for phen-C7 apparently to the point where decarboxylative alcoholysis is favored relative to decarbonylation, but for L4X-C7 the decarbonylation barrier still seems lowest due to the destabilizing effect that this bulkier ligand has on such palladacycles. It is thus concluded that the L2Pd=NPh complex C3 is the prime NPh product-releasing intermediate and only under acidic conditions and in an alcoholic environment may C7-for phenanthroline-become the predominant carbamate product releasing intermediate.

Reductive elimination from arylpalladium cyanide complexes

We report the isolation and characterization of arylpalladium cyanide complexes that undergo reductive elimination to form arylnitriles. The rates of reductive elimination from a series of arylpalladium cyanide complexes reveal that the electronic effects on the reductive elimination from arylpalladium cyanide complexes are distinct from those on reductive reductive eliminations from arylpalladium alkoxo, amido, thiolate, and enolate complexes. Arylpalladium cyanide complexes containing aryl ligands with electron-donating substituents undergo reductive elimination of aromatic nitriles faster than complexes containing aryl ligands with electron-withdrawing substituents. In addition, the transition state for the reductive elimination of the aromatic nitrile is much different from that for reductive eliminations that occur from most other arylpalladium complexes. Computational studies indicate that the reductive elimination of an arylnitrile from Pd(II) occurs through a transition state more closely related in structure and electronic distribution to that for the insertion of CO into a palladium-aryl bond.

Fluoride-induced reduction of palladium(II) and platinum(II) phosphine complexes

A novel redox reaction involving fluoride and phosphine complexes of palladium(II) is reported. The scope of this reaction has been investigated using the ligands PPh3, Ph2P(CH2)nPPh2 (n = 1-4), Ph2PCH2C(CH3)2CH2PPh 2, Ph2PCH3, and P(CH2CH2CN)3; several solvents including DMSO, pyridine, acetonitrile, and THF; and either n-Bu4NF·3H2O or KF/18-crown-6 as the fluoride source. The reduction products are palladium(0) phosphine complexes for which this reaction offers a convenient synthetic route. 31P and 19F NMR spectra permitted identification of the initial oxidation products as difluorophosphoranes (R3PF2), which subsequently hydrolyzed, forming phosphine oxides if a hydrated fluoride source is used. Results implicating a fluoride-induced redox reaction in the thermal decomposition of [(Ph3P)3PdCl]BF4 to yield [Pd3Cl(PPh2)2(PPh3) 3]BF4 are also presented. Preliminary results indicate that platinum complexes also undergo this reaction, but nickel complexes yield NiF2. The X-ray parameters for Pd(dppp)2 (dppp = 1,3-bis(diphenyphosphino)propane) are: monoclinic, space group C2/c (No. 15), a = 18.396 (2) A?, b = 13.290 (1) A?, c = 20.186 (2) A?, β = 109.383 (5)°, and Z = 4.