Carbazoles functionalization

A carbazole-functionalized norbornene derivative, 5-CN-carbazoyl methy-lene)-2-norbornene, CbzNB, was polymerized via ROMP using the ruthenium catalyst Cl2Ru(CHPh)[P(C6Hii)3]2 [100]. The polymerization was conducted in CH2C12 at room temperature, to afford products with polydispersity indices close to 1.3. Subsequent addition of 5-[(trimethylsiloxy)methylene]-2-norbornene showed a clear shift of the SEC trace of the initial polymer, indicating that a diblock copolymer was efficiently prepared in high yield. 

Most of the polymer modifications incorporating benzo-substituted pyrroles have been done with the dibenzo derivative, carbazole, primarily because of its well-known photocon-ductive properties. The modification reaction often involves a substitution reaction on some halogenated polymer. This substitution reaction can be quite facile. Poly(vinylbenzyl chloride), for example, reacts with the potassium salt of carbazole in DMF to yield the carbazole-functional polymer in 97% yield (76MI11110). 

Xin, H., Li, E.Y, Guan, M., etal. (2003) Carbazole-functionalized europium complex and its high-efficiency organic electroluminescent properties. Journal of Applied Physics, 94, 4729-4731. 

W. Wang, Y. Li, and Y.P. Sun, Poly(N-vinyl carbazole)-functionalized single-waUed carbon nanotubes Synthesis, characterization, and nanocomposite thin films. Polymer, 46, 8634-8640 (2005). 

Knapp et al. (2009) introduced polynorbomene PV membrane film for the separation of organics (butanol) from water. Wang et al. (2005) used the carbazole-functionalized norbornene membrane for the separation of aqueous alcohol solution by PV. A higher separation factor and lower permeation rate were achieved for a higher-molecular-weight alcohol. 

Wang, Y.C., Li, C.L., Lee, K.R. and Liaw, D.J. 2005. Pervaporation separation of aqueous alcohol solution through a carbazole-functionalized norbornenederivative membrane using living ring-opening metathesis polymerization. J Memh S l. 246 59-65. 

There are reports of an increasing number of palladium-assisted reactions, in some of which the palladium has a catalytic function. Thus furan and thiophene undergo facile palladium-assisted alkenylation giving 2-substituted products. Benzo[6 Jfuran and TV- acetyl-indole yield cyclization products, dibenzofurans and carbazoles respectively, in addition to alkenylated products (8UOC851). The arylation of pyrroles can be effected by treatment with palladium acetate and an arene (Scheme 86) (81CC254). 

The Ti coordination via the carbocycle prevails for indole and carbazole, although the species were also found in organomanganese and -iridium chemistry. Osmium carbonyls tend to produce the species with the bridging indole function. Some illustrations of the ti N) coordination exist. 

New Diels-Alder reactions of 3-vinylindoles with an aryne selective access to functionalized [a]anellated carbazoles [145]... 

Applying these methodologies monomers such as isobutylene, vinyl ethers, styrene and styrenic derivatives, oxazolines, N-vinyl carbazole, etc. can be efficiently polymerized leading to well-defined structures. Compared to anionic polymerization cationic polymerization requires less demanding experimental conditions and can be applied at room temperature or higher in many cases, and a wide variety of monomers with pendant functional groups can be used. Despite the recent developments in cationic polymerization the method cannot be used with the same success for the synthesis of well-defined complex copolymeric architectures. 

The treatment of 2-fluorophenyl-2-iodophenyl ethers, amines, and thioethers with 3.3 equivalents of f-BuLi and further reaction with selected electrophiles gave rise to functionalized carbazoles, dibenzofurans, and dibenzothiophenes in a direct and regioselective manner. A selected example is illustrated below <06JOC6291>. Benzyl 2-halophenyl ethers was treated with f-BuLi, and then reacted with carboxylic esters to give 2,3-disubstituted benzo[t>]furans <06JOC4024>. 

Intramolecular C-H arylations have been described and are mediated by a variety of palladium complexes, affording a host of heterocyclic products. Carbazoles can be synthesized by a sequential amination/C-H functionalization process (Equation (161)). 

The Buchwald-Hartwig aryl animation methodology cited above in this section was engaged by Hartwig and others to synthesize AT-arylindoles 377 [469]. Carbazole can be N-arylated under these same conditions with p-cyanobromobenzene (97% yield). Aryl chlorides also function in this reaction. The power of this animation method is seen by the facile synthesis of tris-carbazole 378 [469c]. 

Tao et al. reported a series of light-emitting peripheral diarylamine derivatives containing carbazole units, which possess dual functions, as both active emitting materials and HTMs (Scheme 3.12) [79]. These luminescent materials are amorphous, with high Ts (120-194°C),... 

Odabasi, M., Cetin, B., and Sofuoglu, A. Henry s law constant, octanol-air partition coefficient and subcooled liquid vapor pressure of carbazole as a function of temperature Application to gas/particle partitioning in the atmosphere, Chemosphere, 62(7) 1087-1096, 2006. 

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