Dimethylamino stilbenes

MaB zeigt (28 b, 56). Dementsprechend ist auch das Absorptionsspektrum weit weniger nach Rot verschoben als im 4-Nitro-4 -dimethylamino-stilben. 

Prior, to our work on (2 + 2)-photocycloaddition reactions to carbon-nitrogen double bonds, there were only three relevant reports, two of which have subsequently been shown to be in error. Irradiation of N-(4-dimethylaminobenzylidene)aniline (2) was reported to give c/s-4,4 -bis-(dimethylamino)stilbene (2) and azobenzene (5) via an unstable 1,2-diazetidine intermediate (4)4. Ohta and Tokumaru, however, have recently shown that this mode of reactivity is not reproducible5. The only... 

Fig. 11.14 Energy level diagram showing the lowest energy 1PA- and 2PA-allowed states (e and e, respectively) for trans-stilbene (left) and (E)-4,4 -bis(dimethylamino)stilbene (right) according to the quantum-chemical calculations results of Ref. [22], The dotted...

SYNS trans-p-(DIMETHYLAMINO)STILBENE trans-4-DIMETHYLAMINOSTILBENE 4-DIMETHYLAMINO-trans-STILBENE (E)-N,N,-DIMETHYL-4-(2-PHENYL-ETHENYL)BENZENAMINE trans-NN-DIMETHYL-4-STILBENAMINE... 

Fig. 3 cttpa variations with the number of excited states involved in the SOS expression (3) for the 4-dimethylamino-4-nitrostilbene and the dimethylamino)- -stilbene... 

The dynamics of populations of the electronic states in a 4,4 -bis(dimethylamino) stilbene molecule (two-photon absorption) was studied against the frequency, intensity, and shape of the laser pulse [52]. Complete breakdown of the standard rotating wave for a two-photon absorption process was observed. An analytical solution for the interaction of a pulse with a three-level system beyond the rotating wave approximation was obtained in close agreement with the strict numerical solution of the amplitude equations. Calculations showed the strong role of the anisotropy of photoexcitation in the coherent control of populations that can affect the anisotropy of photobleaching. The two-photon absorption cross section of an ethanol solution of a trans-stilbene and its derivatives exposed to radiation of the second harmonic of a Nd YAG laser (532 nm) of nanosecond duration has been detected [53]. In experiments, the method based on the measurement of the photochemical decomposition of examined molecules was used. The quantum yield of the photoreaction (y266) of dyes under one-photon excitation (fourth harmonic Nd YAG laser 266 nm) was detected by absorption method. 

A combined fluorescence-photochrome approach was used for investigating the molecular dynamics of anti-DNP antibody binding site and its cavity. A 4-(N-2,4-dinitrophenylamino)-4 -(N,N -dimethylamino)stilbene (StDNP) fluorescence DNP analogue was incorporated into the antibody binding site [56]. This was followed by measurements of fluorescence and photochrome parameters such as the StDNP... 

In the same year, Lequan et al. presented [4-(dimethylamino)stilben-E-4 -yl]dimesitylborane (BNS), dimesitylboron-containing E- and Z-stilbenes (Figure 13.22), and the measurement of their second-order optical nonlinearities (Lequan et al., 1992b). 

M. Lequan, R. M. Lequan, K. Chane-Ching, A.-C. CaUier, M. Barzoukas, A. Fort, Second-order optical non-linearities of 4-(dimethylamino) stilben Z E 4 -yl Dimesityl borane. Adv. Mater. Opt. Elect. 1992,... 

In the first case, 4 -(dimethylamino)stilbene-4-boronic acid 59, the electron-donating dimethylamino moiety is the donor group. When boron is sp hybridised, and therefore an acceptor, excited-state ICT can occur between the amino donor and boron acceptor, redshifting the emission wavelength of the sp species. 

Lapouyade R, Czeschka K, Majenz W, Rettig W, Gilabert E, Rulliere C (1992) Photophysics of donor-acceptor substituted stilbenes. A time-resolved fluorescence study using selectively bridged dimethylamino cyano model compounds. J Phys Chem 96(24) 9643-9650... 

The photocyclization has been found not to occur with stilbenes substituted with acetyl, dimethylamino, or nitro groups, lodo substituents are replaced by hydrogen by photolysis in cyclohexane solution. w-Substituted stilbenes give mixtures of 2- and 4-substituted phenanthrenes which generally are difficult to separate. 

Reaction of the TMS-nitro compound 1496 and the indole carboxaldehyde 1497 with a catalytic amount of TBAF led to the desired alcohol 1498, which, on further treatment with TFAA, followed by elimination of the corresponding trifluoroacetate with DBU, afforded the frans-stilbene 1499. Reductive cyclization of 1499 under Cadogan-Sundberg conditions afforded the bisindole 1500. Finally, condensation of 1500 with (dimethylamino)acetaldehyde diethyl acetal led to tjipanazole D (359) in 71% yield (796) (Scheme 5.255). 

Ole/m synthesis, Eastwood ei al. have reported a new method for conversion of W -diols into alkenes. For example, rut-1,2-diphenylethane-l,2-diol (1) is heated with N,N-dimcthylformamide dimethyl acetal to give 2-dimethylamino-/rani -4.5-diphenyl-1,.3-dioxolanc (2). When this dioxolane is heated with acetic anhydride at 165-180° rruns-stilbene (3) is formed in 80% yield. Similarly, meso-l,2-diphenylethane-l,2-diol is converted into m-stilbene (75%) and a trace of truns-stilbene if the elimination... 

Another example of intramolecular CT complex formation is provided by trans-4-dimethvlamino-4 -(1-oxobutvl)stilbene Solvent effects on the spectrum give a value of 22D for the excited state dipole moment. The effect of electric field on the fluorescence of 4-(9-anthry1)-N.N.-2.3,5,G-hexamethy1-aniline shows this compound forms an excited state whose dipole moment does not change with solvent . Chiral discrimination in exciplex formation between 1-dipyrenylamine and chiral amines is very weak . In the probe molecule PRODAN (6-propionyl)-2-(dimethylamino)—naphthalene the initially formed excited state converts to a lower CT state as directly evidenced by time-resolved spectra in n-butanol. Rate constants for intramolecular electron transfer have been measured in both singlet and triplet states of covalently porphyrin-amide-quinone molecules . Intramolecular excimer formation occurs during the lifetime of the excited state of bis-(naphthalene)hydrazides which are used as photochemical deactivators of metals in polyethylene . ... 

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