Vinylanthracene

As a part of a broad study dealing with the development of synthetic methods for polycyclic aromatic compounds, Minuti and colleagues77 prepared some [5]phenacenes and fluorenoanthracenes via Diels-Alder reactions between dienes such as 59 and several activated dienophiles. Oxidation of the primary adducts with DDQ afforded the desired polycyclic aromatic compounds. Equation 21 shows the reaction between 3,4-dihydro-1-vinylanthracene (59) and in situ generated 2-inden-l-one (60) which afforded a 3 1 mixture of regioisomers 61 and 62 with 51% overall yield. 

Vinylanthracene [2444-68-0] M 204.3, m 65-67 , b 61-66 /10mm. Purified by vacuum sublimation. Also by chromatography on silica gel with cyclohexane as eluent, and recrystd from EtOH [Werst et al. JACS 109 32 1987]. 

The effects of limited molecular flexibility and increasing deviation from coplanarity of the anthracene and ethylene ir-systems on the radiative properties have been assessed in a series of symmetrically 2,2-substituted l-(9-anthryl)ethylenes 87 [63]. As for structurally rigid 9-anthrylethylenes 88 and 89, for which rotation about the anthryl-ethylene single bond is not possible, and in which the ethylene double bond has been forced to be coplanar with the anthracene -system, their fluorescence quantum yields in cyclohexane are exceptionally high, i.e., 0.94 and 0.96, respectively, and the Stokes shifts are less than 200 cm 1 (see Figure 15). For nonplanar 9-vinylanthracene 87a and its dimethyl derivative 87b, whose ethylene double bond may be twisted out of the plane of the anthracene by about 60°, the quantum yield is 0.63, and the Stokes shifts are around 1000cm-1 (see Table 16). 

Polymers with anthracene groups such as poly(9-vinylanthracene)46 48), poly(l-vinylanthracene) and poly(2-vinylanthracene)49 so), poly[ l-(2 -anthryl)-ethylmethacrylate]51 poly(vinyl-p-phenyl-9-anthracene)S2 55 and poly(9-p-expoxy-... 

The dry nature of CVD process enables copolymerization more easily than solution based techniques. This approach has been utilized to tailor the thermal and electrical properties of parylene thin films for ULSI applications. One of the first reports of vacuum copolymerization of xylylene was done with maleic anhydride as the comonomer. Subsequently, 9-vinylanthracene, 4-vinylbiphenyl and perfluoro-octyl methacrylate were successfully copolymerized with parylenes, and reported in... 

The introduction of LM into the main chain of polymers is more difficult. For this purpose, a method based on free-radical copolymerization with the participation of 9-vinylanthracene (III) proceeding according to Scheme 2 has been developed. 

The photodimerisation of anthracene derivatives normally produces 4+4 adducts and if the 9-position of the anthracene is substituted then the product generally possesses the anti regio-chemistry shown in (296). The adduct derived from 9-vinylanthracene conforms with this generalisation and has been assigned the structure... 

For most of the compounds examined the excited state has an enhanced dipole moment compared with the ground state. This reflects the greater basicity of the double bond of the excited vinylarene and rationalises the fast and efficient protonation reaction which is observed. 9-Vinylanthracene was found to be an exception in that the excited state dipole moment was determined to be zero. This correlates with the fact that the dominant photochemical reaction of vinylanthracene is dimerisation to give (297) rather than hydration. 

Usually rotational isomerization cannot take place in the excited state as proposed by Havinga (NEER principle) [105,106]. The excited singlet state of 2c follows this principle, t. -ever, in 2-vinylanthracene and its alkyl derivatives. 

In the photopolymerisation of methyl methacrylate induced by mixtures of chloroacetic acid derivatives and dimethylaniline the kinetics were found to be influenced by the degree of substitution of the chlorine atoms while the initiation occurred through a complex S. Ethyl aluminium sesquichloride has been found to induce the photocopolymerisation of 9-vinylanthracene with methyl methacrylate at -20°c while photochromic polymers have been made by reacting para-bromoazobenzene with ethylene gas O. Surface active N-cetylpyridinium bromide and chloride have been found to... 

Photopolymerization of acrylonitrile in the presence of naphthalene and its derivatives,19 of 9-vinylanthracenes,20 and of sulphonyl activators for dye-photosensitized polymerization,21 and the polymerization of MMA photo-initiated by anthraquinone (AQ) and 2-t-butylanthraquinone22 have been reported. Some of the important steps in this latter process are shown in reactions... 

In benzene the time-resolved fluorescence spectra of 2-vinylanthracene show one-way rotation from a rotamer showing shorter-wavelength fluorescence to another with longer-wavelength fluorescence [136] similar to 11. Substitution of a t-butyl and methyl group on the terminal carbon of 2-vinyl-anthracene, that is, trans-6 and 6b, leads to similar internal rotations in the excited singlet state. The activation energies and the frequency factors for the internal rotation are 3.9, 4.3, and 4.3 kcal mol and 1.7, 1.8, and 1.8 x 10" s , for 2-vinylanthracene, 6a, and 6b, respectively. 

However, substitution of a phenyl or a naphthyl group on the terminal carbon of 2-vinylanthracene inhibits single-bond rotation in the excited singlet state. Irradiation of trans-6c and 6d with 316-nm laser light excites both s-trans and s-cis rotamers to give fluorescence of both rotamers. The... 

FIGURE 26. Plots of 1/P against T/n for poly( -chlorostyrene-9-vinylanthracene) co-polymer 1n toluene. P = degree of polarization, T temperature °K, n = viscosity (see text) [after figure 5, J. Chem. Soc. Faraday Trans. 1, 1101... 

Poly( -chlorostyrene) 9-vinylanthracene co-polymer (average of two samples) toluene 6.6... 

Poly (2.-bromostyrene) Poly(N-vinylcarbazole) 9-vinylanthracene co-polymer toluene 5.5... 

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