نتایج جستجو برای: phosphines
تعداد نتایج: 579 فیلتر نتایج به سال:
Three protocols that involve the cleavage of Au−P bond in Au-substituted phosphines (AuPhos) have been demonstrated, namely i) direct demetallation with a strong anionic base; ii) protonation followed by neutral iii) oxidation-triggered metal migration. Specifically, (CAAC)AuPPh2 (1 a) (CAAC=cyclic (alkyl)(amino)carbene) KP(TMS)2 or LiC(N2)TMS yields (CAAC)AuPTMS2 (2) (CAAC)AuC(N2)TMS (3), resp...
A series of phosphine donor-stabilized N-silylphosphoranimine salts [R'3P.PR2=NSiMe3]+Br- were prepared from the direct reaction between the phosphoranimines BrR2P=NSiMe3 (R = Me, OCH2CF3) and the tertiary phosphines nBu3P and Me3P. The 1JPP values of these salts exhibit an unusual dependence on the substituents at the phosphoranimine acceptor and appear to reflect an electronic push-pull mecha...
ABSTRACT Ru-catalyzed synthesis of mixed alkyl-alkyl acetals via addition of primary alcohols to allyl ethers has been extended to include long-chain and/or functionalized substrates. The catalytic systems for these reactions were generated from RuCl2(PPh3)3 and [RuCl2(1,5-COD)]x and phosphines [PPh3 or P(p-chlorophenyl)3] or SbPh3. Of particular importance is the almost quantitative eliminatio...
The rigid linkers E(p-C6H4PPh2)4 (E = Si, Sn) have been synthesized from the corresponding precursors E(p-C6H4Br)4 and immobilized by forming one (E = Si) or three (E = Sn) phosphonium groups that are attached to the silica support by electrostatic interactions. The remaining unquaternized phosphines are coordinated to Wilkinson-type Rh complexes. The catalyst immobilized by the rigid scaffold ...
A sterically demanding molybdenum(VI) dioxo complex was found to catalytically activate molecular oxygen and to transfer its oxygen atoms to phosphines. Intermediate peroxo as well as reduced mono-oxo complexes were isolated and fully characterized. Monomeric Mo(IV) monooxo species proved to be of an unusual nature with the coordinated phosphine trans to the oxo group. The reduced molybdenum ce...
Aziridine-based cofactor mimics have been synthesized and are shown to undergo methyltransferase-dependent DNA alkylation. Notably, each cofactor mimic possesses an azide functionality, to which can be attached an assortment of unnatural groups following methyltransferase-dependent DNA delivery. DNA duplexes modified with these cofactor mimics are capable of undergoing the Staudinger ligation w...
A series of phosphines incorporating (C6Cl5) substituents, Ph2P(C6Cl5) 1, PhP(C6Cl5)22, P(C6Cl5)33 and (C6F5)P(C6Cl5)24 were prepared. In the case of 1, 2 and 4, these were converted to the corresponding aryl-difluorophosphoranes 5-7via reaction with XeF2, whereas reaction of 3 with XeF2 afforded only an inseparable mixture of products. The compounds 5-7 were converted to the fluorophosphonium ...
5-Amino-2,3-dihydrophthalazine-1,4-dione (Luminol 1) reacted with some organophosphorus reagents such as phosphonium ylides, trialkyl phosphites, and tris(dialkylamino)phosphines to afford the corresponding olefinic products 5a-e, alkoxy-, dialkylamino derivatives of Luminol 6a-e. 4-Thioxo-3,4-dihydrophthalazin-1(2H)-one derivative 7 was synthesized from reaction (1) thiating Lawesson Japanese ...
Chiral rhodium complexes covalently anchored on carbon nanotubes for enantioselective hydrogenation.
Chiral rhodium hybrid nanocatalysts have been prepared by covalent anchorage of pyrrolidine-based diphosphine ligands onto functionalized CNTs. This work constitutes the first attempt at covalent anchoring of homogeneous chiral catalysts on CNTs. The catalysts, prepared with two different chiral phosphines, were characterized by ICP, XPS, N2 adsorption and TEM, and have been tested in the asymm...
Two novel modified 2'-deoxyuridine triphosphates carrying an azide functionality linked to the nucleobase were synthesized. For probing the sterical influence on enzymatic incorporation and Staudinger ligation, differently sized flexible linkers were chosen. Both nucleotides can completely replace natural thymidine in primer extension as well as polymerase chain reaction (PCR) using Pyrococcus ...
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