نتایج جستجو برای: phosphines
تعداد نتایج: 579 فیلتر نتایج به سال:
A series of new triazolopyridine-based phosphines has been prepared. These compounds revealed unexpected spectroscopic patterns. In particular, the NMR spectra are highly dependent on the relative conformational preference of the phosphine substituent at C7. Here, we report on their complete NMR analysis, X-ray structures and DFT calculations that confirm the particular arrangement of the phosp...
The use of the commercially available, bifunctional phosphine 1,3,5-triaza-7-phosphaadamantane (abbreviated as PN3) in conjunction with a series of Zn(salphen) complexes leads to sterically encumbered phosphine ligands as a result of (reversible) coordinative Zn-N interactions. The solid state and solution phase behaviour of these supramolecular ligand systems have been investigated in detail a...
Tris(perfluoroalkyl)phosphines, of interest as tunable alternatives to the carbon monoxide ligand, can be synthesised by the nucleophile mediated reaction of perfluoroalkyltrimethylsilanes with triphenylphosphite; the method can be extended to diphosphines.
We report a synthesis method for the construction of quaternary aryl phoshonium salts at ambient temperature. The regiospecific reaction involves the coupling of phosphines with aryl radicals derived from diaryliodonium salts under photoredox conditions.
Isomerism in rhodium(I) N,S-donor heteroscorpionates: ring substituent and ancillary ligand effects.
The heteroscorpionate ligands [HB(taz)(2)(pz(R))](-) (pz(R) = pz, pz(Me2), pz(Ph)) and [HB(taz)(pz)(2)](-), synthesised from the appropriate potassium hydrotris(pyrazolyl)borate salt and 4-ethyl-3-methyl-5-thioxo-1,2,4-triazole (Htaz), react with [{Rh(cod)(μ-Cl)}(2)] to give [Rh(cod)Tx] {Tx = HB(taz)(2)(pz), HB(taz)(2)(pz(Me2)), HB(taz)(2)(pz(Ph)), HB(taz)(pz)(2)}; the heteroscorpionate rhodabo...
The stoichiometric reaction of trityl cation with two equivalents of Ph2PH affords the phosphine stabilized phosphenium salt [Ph2(H)PPPh2][B(C6F5)4] via hydride abstraction, while catalytic amounts of B(p-HC6F4)3 effects catalytic phosphine dehydrocoupling with the liberation of H2. This reaction is accelerated by the presence of olefin or imine, effecting concurrent hydrogenation.
Catalytic dehydrocoupling of primary and secondary phosphines has been achieved for the first time using an iron pre-catalyst. The reaction proceeds under mild reaction conditions and is successful with a range of diarylphosphines. A proton acceptor is not needed for the transformation to take place, but addition of 1-hexene does allow for turnover at 50 °C. The catalytic system developed also ...
Reactions of the bis(pyridine) complex (H2IMes)(Py)2(Cl)2Ru(=CHPh) and fluorous phosphines P(CH2CH2R(fn))3 (n = a, 6; b, 8; c, 10; R(fn) = (CF2)(n-1)CF3) give (H2IMes)(P(CH2CH2R(fn))3)(Cl)2Ru(=CHPh) (2a-c, 64-73%), which are analogs of Grubbs' second generation catalyst and effective alkene metathesis catalysts under organic monophasic and fluorous/organic biphasic conditions. The latter give r...
Design and synthesis of chiral phosphines have played a significant role in the development of transition metal catalyzed asymmetric reactions.1 Many excellent chiral bidentate phosphines such as DIPAMP,2 DIOP,3 Chiraphos,4 and BINAP5 have been developed for a variety of catalytic reactions. Recent additions to this family of ligands include the Duphos and BPE species of Burk and co-workers.6 T...
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