Norbomenes functionalized

Figure 8. Structure of norbomene-functionalized Co(salen) complexes 23, 24.

Twieg and coworkers, reported preparation of poly(norbomene) copolymers functionalized with nonlinear optical chromophore side groups. Use was made of (ri -toluene)Ni(C6F5)2, catalyst in the polymerization of norbomene. The nickel complex used to polymerize the norbomene monomers is tolerant to many functional groups found in nonlinear optical chromophores. On the other hand, nitriles and amines other than trisubstituted amines strongly inhibit the reaction. A copolymer of hexylnorbomene and a norbomene-functionalized Disperse Red I chromophore was scaled up and studied in detail. Initial studies indicate that electric field poling is effective but that relaxation of polar order in the poly(norbomene) is faster than in a comparable methacrylate copolymer. The copolymer can be illustrated as follows ... 

Some catalyst supporting polymers have been accessed through grafting. Norbomene-functionalized silica and... 

The precise control of ROMP methodology has been exploited by Schrock and co-workers in the polymerization of a norbomene monomer functionalized with a distyrylbenzene side-chain 70 [1051. When calcium is used as a cathode, an internal device efficiency of 0.3% is observed and the peak emission is in the blue (475 nm). 

Norbomene derivatives are very popular monomers for ROMP due to a comparably high ring strain and good functionalisability. The latter is needed to append any desired functional unit to the monomer [98, 99]. 

Selective aromatic functionalization has been a permanent object of research since the ninenteenth century. Catalysis has offered a powerful tool to achieve this goal. Over the years we have worked out a complex catalytic system consisting of an inorganic compound such as a palladium salt and an organic molecule containing a strained double bond such as norbomene (1,2). We have seen that these two catalysts cooperatively react with an aromatic iodide, an alkyl iodide and a terminal olefin. The following equation reports an example (L = solvent and/or olefin) (3). 

Each of these polymers exploit the ability of the group 10 metal catalysts used to tolerate functional groups and to copolymerise norbomene monomers bearing esters etc. into the polymer backbone. In the case of low-k dielectric polymers (Avatrel ) low levels (2-10 mol %) of 5-triethoxysilylnorbomene are used to impart good adhesive properties, the remaining 90+% of the monomer being a 5-alkylnorbomene. The alkylnorbomene is selected to tailor... 

The optimum catalyst for a given reaction depends primarily on (a) the energetics of the reaction and (b) the functional groups present in the substrate. If, for instance, a strained cycloalkene such as norbomene or cyclobutene is to be polymerized, a catalyst of low activity will be sufficient to attain acceptable reaction rates. RCM... 

In addition to the role of substituents in determining regioselectivity, several other structural features affect the reactivity of dipolarophiles. Strain increases reactivity. Norbomene, for example, is consistently more reactive than cyclohexene in 1,3-dipolar cycloadditions. Conjugated functional groups also usually increase reactivity. This increased reactivity has most often been demonstrated with electron-attracting substituents, but for some 1,3-dipoles, enamines, enol ethers, and other alkenes with donor substituents are also quite reactive. Some reactivity data for a series of alkenes with a few 1,3-dipoles are given in Table 6.3. Scheme 6.5 gives some examples of 1,3-dipolar cycloaddition reactions. 

As stoich. [Ru(0)(bpy)(tmtacn)]VCH3CN it functioned as a competent (sic) epoxidant for alkenes, though the products were often contaminated with by-products (e.g. fran -stilbene gave fran -stilbene oxide and benzaldehyde cw-stilbene gave cis- and trans- epoxides). Kinetics of the epoxidation of norbomene and styrene were reported, with activation parameters measured and discussed [682]. Kinetics of its non-stereospecific, stoicheiometric epoxidation of aromatic alkenes in CH3CN were studied, and the rates compared with those of oxidations effected by other Ru(IV) 0x0 complexes with N-donors, e. g. [Ru(0)(tmeda)(tpy)] ", trans-[Ru(0)(Cl3bpy)(tpy)] " and [Ru(0)Cl(bpy)(ppz )] + [676]. 

Nair KP, Week M. Noncovalently functionalized poly(norbomene)s possessing both hydrogen bonding and coulombic interactions. Macromolecules 2007 40 211-219. 

Although the alkylidene complexes initiate the ROMP of functionalized norbomenes and 7-oxanorbomenes in aqueous solution quickly and completely in the absence of acid, the propagating species in these reactions often decompose before the polymerization reaction is complete. For example, in the ROMP of the water-soluble... 

Norbomene was functionalized with cyclodextrins and surface grafted onto silica-based supports using ROMP (44). The CSP are suitable for the enantioselective separation various amino acids, including jS-blockers and other compounds, such as chiral ferrocene derivates. 

J.P. Mathew, A. Reinmuth, J. Melia, N. Swords, and W. Risse, (ry-3-allyl) palladium (ii) and palladium (ii) nitrile catalysts for the addition polymerization of norbomene derivatives with functional groups, Macromolecules, 29(8) 2755-2763,1996. 

It is apparent from extensive reviews of the induction of monooxygenase activity by xenobiotics that many compounds other than methylenedioxyphenyl compounds have the same effect. It may be that any synergist that functions by inhibiting microsomal monooxygenase activity could also induce this activity on longer exposure, resulting in a biphasic curve as described previously for methylenedioxyphenyl compounds. This curve has been demonstrated for NIA 16824 (2-methylpropyl-2-propynyl phenylphosphonate) and WL 19255 (5,6-dichloro-l,2,3-benzothiadiazole), although the results were less marked with R05-8019 [2,(2,4,5-trichlorophenyl)-propynyl ether] and MGK 264 [A-(2-ethylhexyl)-5-norbomene-2,3-dicarboximide],... 

The proposed idea that metal alkyhdene complexes are be able to catalyze olefin metathesis was confirmed in 1980 [8] and consolidated in 1986 by Schrock with the development of the first well-characterized, highly active, neutral tungsten (Cl, Fig. 3) [9] and molybdenum (C2) [10] alkylidene complexes. These complexes were able to catalyze both the metathesis of different olefins and the ROMP of functionalized norbomene to polynorbomene with low polydispersities [11]. Moreover, these catalysts were used by Wagener and coworkers to perform the first quantitative ADMET polymerization [12] and copolymerization [13] of 1,5-hexadiene and 1,9-decadiene. However, the low stability of these catalysts in... 

Scheme 24 Synthesis of random and block copolymers via ROMP of amino acid-functionalized norbomenes [173]...

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