Fluorene fused rings

Eused-ring polycycHc fluoroaromatics can be made from the corresponding amino fused-ring polycycHc or from preformed fluoroaromatics, eg, 4-fluorophenyl-acetonitrile [459-22-3] (275). Direct fluorination techniques have been successfully appHed to polycycHc ring systems such as naphthalene, anthracene, benzanthracenes, phenanthrene, pyrene, fluorene, and quinoHnes with a variety of fluorinating agents xenon fluorides (10), acetyl hypofluorite (276), cesium fluoroxysulfate (277), and electrochemical fluorination (278,279). 

PolycycUc Hydrocarbons, Nonalternant Compounds with More Than Five Fused Rings Polycyclic Hydrocarbons, Nonalternant Compounds with Two or Three Fused Rings Fluorene Indene... 

Fluoranthene under Polycyclic Hydrocarbons, Nonaltemant Compounds with Four Fused Rings Fluorene under Polycyclic Hydrocarbons, Nonaltemant Compounds with Two or Three Fused Rings... 

In these reactions, however, the formation of the fused rings takes place by 1-5 or 1-6 ring closure between two aromatic carbon atoms. In contrast, the formation of fluorene and 9-methylfluorene from 2-methyl- and 2-ethyl-diphenyl, respectively (752) is much closer to the 1-5 ring closure observed with paraffinic hydrocarbons (Scheme 78). 

Fused polycyclic iminoxyls with central system 5.12.2.1 5-Membered rings derivatives of indan, indoline, and fluorene... 

In fish, the half-lives of PAHs are generally very short. Half-lives of 6-9 days for fluorene, phenanthrene, anthracene, and fluoranthene were reported in rainbow trout [Oncorhynchus mykiss (Salmo gairdneri)] fed oil spiked with PAHs (Niimi and Palazzo 1986). Niimi and Dookhran (1989) also reported half-lives of 1-4 d for acenaphthylene, methylanthracene, triphenylene, and perylene in rainbow trout. They reported a much longer half-life (25 d) for phenylnaphthalene compared to other PAHs and speculated that it may be more recalcitrant to metabolism because its aromatic rings are not all fused. 

Particularly, benzofused Cp derivatives such as indene and fluorene had serious impact on the development of catalyst precursors for stereospecific olefin polymerization [17]. However, fusing aromatic ring systems to the cyclo-pentadienyl ring can sometimes cause problems with regard to the bonding situation between metal and ligand because the tendency of the benzofused ring to preserve its aromatic six-electron system leads to a haptotropic shift as depicted in Scheme 6.2. 

Ferroelectric liquid crystals having a heterocyclic pyrimidine, pyrazine, or pyridazine ring have been developed. Phenylpyrimidine systems show a characteristic low rotational viscosity, and fused aromatics, such as fluorene, fluorenone, or naphthalene, have been discussed from the viewpoint of dipole moment, spontaneous polarization, and orientability. 

Larocket fl/. in 2000 developed the fluoren-9-one synthesis by the cyclocarbonyla-tion of ort/zo-halobiarys with a commercially available Pd(PCy3)2 catalyst [17] This procedure was initiated by the palladium(0) and could be utilized to the synthesis of polycyclic and heterocyclic fluorenones containing the fused isoquinoline, indole, pyrrole, thiophene, benzothiophene, and benzofuran rings (Table 15.12). 

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