2-Amino-4-nitrostilbene

HPLC and GC methods were used for analysis of water-soluble nitro-substituted aromatic sulfonic acids523. For example, 4-amino-4 -nitrostilbene-2,2 -disulfonic acid (248)... 

Laser flash photolysis (30 ns, 50 mj, 347 nm) of 4-nitrostilbene, 4,4 -dinitro-stilbene, 4-nitro-4 -methoxystilbene and 4-dimethyl-amino-4 -nitrostilbene permits the observation of transients 133) por the latter two compounds, the lifetime and the absorption spectra of the transients vary strongly with the polarity of the solvent used. First order decay rate constants are given in Table 4. 

The prototypical organic material with high P (all values of P quoted here are for 1.06 1 light unless noted) is p-nitroaniline (PNA). In electrostatic units (esu), P for PNA is 34.5 x 10 30 esu. (37) It has a dipole moment of 6.8 D. Extension of the chromophore by insertion of a single double bond to produce 4-amino-4 -nitrostilbene increases P dramatically 248 x 10"30 esu. (38) However, both crystalline materials are centrosymmetric, and so no SHG is possible. Most achiral molecules crystallize in centrosymmetric space groups, but some do not. Several materials have been discovered during the last few years which have combinations of hyperpolarizability, crystal growth and habit, and linear spectral properties which make them candiates for useful NLO materials. As will be obvious from the comparison, considerable compromise must be made to yield a practical material. 

We have calculated lig and /Jzzz for 4-dimethylamino-4 -methylsulfonylstilbene (VI), and compared these data with values for 4-dimethyl-amino-4 -nitrostilbene (DANS, VII). We have also included the azo-derivatives VIII and IX in the comparison (Table I). Calculated values of j5z for III, IV, VI, and VII as a function of basis set size are shown in Figure 1. It is evident that in all of these cases, there is a single excited state that provides the largest contribution to the hyperpolarizability. 

One photorefractive polyimide 59 was formed by linking thee units, a substituted porphyrin (charge generator), 4-amino-4 -nitrostilbene derivative (the nonlinear optics molecule), and a charge transporting agent, pyromellitic dianhydride. This polyimide retains its nonlinear optical properties even after... 

Asymmetric derivatives can be synthesized by 4-amino-4 -nitrostilbene-2,2 -disulfonic acid however, their preparation is more expensive, and they show little advantage over the symmetrical compounds. The principal effects of structural variations are changes in solubility, substrate affinity, acid fastness, etc. The bistriazinyl brighteners are anployed principally on cellulosics such as cotton or paper. 2-(Stilben-4-yl)-naphthotriazoles (34, 35) are prepared by diazotization of 4-aminostilbene-2-sulfonic acid or 4-amino-2-cyano-4 -chlorostilbene, coupling with an orthocoupling naphthylamine derivative, and finally, oxidation to the triazole. 

Copolymer. 4-(iV -2-methyacroyolxyelhyl-N-methyl-amino-4 -nitrostilbene and methyl methacrylate. Cross-linked polymer polyurethane polymer containing Disperse Red 19 chromophores. 

Synthesis of N,N-diethanol-4 -amino-4-nitrostilbene (16). A mixture of of 4-bromo-N,N-diethanolaniline (0.872 g, 3.35 mmol), 4-nitrostyrene (0.500 g, 3.35 mmol), Pd(OAc)2 (0.0752 g, 0.335 mmol), tri-o-tolyl phosphine (0.204 g, 0.670 mmol), and Et3N (0.513 mL, 3.685 mmol) in DMF was heated in a screw tapped tube purged with argon at 90 C for 48 h. The reaction mixture was cooled, filtered, and poured into ice cold water. The organic layer was extracted with EtOAc. The organic extract was dried over MgS04 solvent removed in vacuo. Stilbene... 

A nitro analog to polyurethane 19 was prepared by triethylamine-catalyzed polycondensation of (N,N-diethanol)-4 - amino-4-nitrostilbene 16 and the chaige transporting diisocyanate 17 (Figure 6). The Xj for 19 was also 316 nm but its absorption extended out to 548 nm. The H NMR spectrum was consistent with the polyurethane structure. The TGA analysis revealed high thermal stability of the polymer, with decomposition beginning at 247. The Tg of polyurethane 19 was... 

The parameters that can be changed at the molecular level are the relative electron affinities of the donor and acceptor groups and the length as well as the nature of the conjugated segment connecting the donor to the acceptor. The chemical structures of some of the NLO chromophores such as 4-(dimethyl-amino)-4 -nitrostilbene (DANS) (a). Disperse Red 1 (b), l-(2 -ethylhexyloxy)-2, 5-dimethyl-4-(4 -nitrophenylazo)benzene (EHDNPB) (c), N,N-diethyl-substituted... 

A comprehensive comparison among different expressions was done by Koutek, in a remarkable paper of the late 1970s [201] on the basis of the data available for 9 compounds, viz. carbazole, indole, l,3-diphenyl-2-pyrazoline, (hexamethyl-benzene + tetrachlorophthalic anhydride) CT-complex, 4-amino-4 -nitrostilbene, 4-dimethylamino-benzonitrile, 4-dimethylamino-4 -nitrostilbene, 4-dimethylamino-co-nitrostyrene, and 4-dimethylamino-benzylidene-4 -nitroaniline. Unfortunately, the analysis was limited to neutral molecules characterised by the presence of a symmetry axis, or at least by expected co-directional electric dipole moment vectors. 

FDA and urea for few hours [179, 180]. Some of the NLO chromophores [179, 180] used in this method are 2-[3-(2- 4-[bis-(2-hydroxy-ethyl)-amino]-phenyl -vinyl)-5,5-dimethyl-cyclohex-2-enylidene]-malononitrile [179], 4-[N,N-bis(hydroxyethyl)amino]-4 -nitrostilbene [179], 4-[N,N-bis(hydroxyethyl)amino]-4 -nitroazobenzene [179], 4-[N,N-bis(hydroxyethyl)amino]-2 -methyl-4 -nitroazobenzene [179], 4-[N,N-bis (hydroxyethyl) amino]-4 -cyanoazobenzene [179],4-[N,N-bis(hydroxyethyl)amino]-4 -formylazobenzene [180] and 2-[[4-(4-[l,3]dioxolan-2-yl-phenylazo)-phenyl]-(2-hydroxy-ethyl)-amino]-ethanol [180] and their chemical structures are given in figure 34. 

---