Transition metal complexes fluorinated

We are continuing to study the synthesis, structure, and reactivity of highly electrophilic early transition metal complexes. Fluorine containing ligands and counterions are playing an increasingly important role in these studies because of the low reactivity associated wifli the strong carbon-fluorine bonds. 

The curing reaction can be carried out thermally or with the addition of a catalyst. The thermal cure is strongly influenced by impurities associated with the synthesis. The greater the degree of monomer purity, the more slowly the thermal cure proceeds. If the monomer is sufficiently purified, the cure rate can be predictably controlled by the addition of catalysts. As with the aromatic cyanate esters, the fluoromethylene cyanate esters can be cured by the addition of active hydrogen compounds and transition metal complexes. Addition of 1.5 wt% of the fluorinated diol precursor serves as a suitable catalyst.9 The acetylacetonate transition metal salts, which work well for the aromatic cyanate esters,1 are also good catalysts. 

Proton NMR spectra of some V1" and Cr1" complexes indicated a facial octahedral configuration with all three sulfur atoms cis.234 More recent 13C and 19F NMR data on a wide range of transition metal complexes of fluorinated monothio-/ -diketones support the assignment of cis square-planar and facial octahedral geometries.235,236 X-Ray structural data have established the cis square-planar configuration for a Pd" and a Pt" complex237 and four Ni" complexes,238,239 the tetrahedral configura-... 

Transition metal complexes containing fluorinated ligands date back to the initial explosive development of organometallic chemistry in the period from 1950 to 1970, and some early reviews contain a great deal of useful and relevant information (3,6,7). Early work clearly established that these compounds do indeed exhibit dramatically different structural, bonding, and chemical... 

Abstract Pressure-sensitive paint (PSP) is applied to the areodynamics measurement. PSP is optical sensor based on the luminescence of dye probe molecules quenching by oxygen gas. Many PSPs are composed of probe dye molecules, such as polycyclic aromatic hydrocarbons (pyrene, pyrene derivative etc.), transition metal complexes (ruthenium(II), osumium(II), iridium(III) etc.), and metalloporphyrins (platinum (II), palladium(II), etc.) immobilized in oxygen permeable polymer (silicone, polystyrene, fluorinated polymer, cellulose derivative, etc.) film. Dye probe molecules adsorbed layer based PSPs such as pyrene derivative and porphyrins directly adsorbed onto anodic oxidised aluminium plat substrate also developed. In this section the properties of various oxygen permeable polymer for matrix and various dye probes for PSP are described. 

Bruns and Haufe have described the first examples of a transition metal complex mediated asymmetric ring opening (ARO) of both meso- and racemic epoxides via formal hydro-fluorination [23]. Initial attempts with chiral Euln complexes led to very low asymmetric induction. Opening of cyclohexene oxide 30 with potassium hydrogendifluoride in the presence of 18-crown-6 and a stoichiometric amount of Jacobsens chiral chromium salen complex 29 [24a] finally yielded two products 31 and 32 in a 89 11 ratio and 92% combined yield, the desired product 31 being formed with 55% ee. Limiting 29 to a catalytic amount of 10 mol% led to an increase in the ratio of 31, however, with the enantiomeric excess dropping to 11% (Scheme 5). 

Hydrosilylation is by far the most important route for obtaining monomers and other precursors to fluorinated polysiloxanes. Hydrosylilation80 is the addition of silicon hydride moiety across an unsaturated linkage using transition metal complexes of platinum or rhodium such as Speier s catalyst, hexachloroplatinic acid in isopro-... 

The design of transition metal complexes capable of C—F bond activation for the functionalization of fluorocarbons has attracted attention recently. It has been known for several years that oxidative addition of an aromatic C—F bond takes place at tungsten(O) to yield stable tungsten(II) metallacycles, the cleaved carbon and fluorine atoms both finishing up bound to the metal centre (Eqn. (2)) [34-36]. 

R. Fields Fluorine-19 Nuclear Magnetic Resonance Spectroscopy, pp. 99-304 (513), esp. pp. 255 -286, Transition metal complexes of fluorinated molecules. 

Fluorophosphines are tervalent phosphorus compounds containing phosphorus-fluorine bonds and they often show markedly different chemical behavior compared with other halogenophosphines. This article is mainly concerned with recent advances in the chemistry of derivatives of PF 3 of the type PF3 X , with particular reference to (a) synthesis of new structural types, (6) the role of fluorophosphines as ligands, particularly in transition metal complexes, and (c) nuclear magnetic resonance (NMR) studies. 

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