Stilbazole derivatives

Bulk NLO studies on luminescent /uc- ReI(CO)3(a-diimine) + complexes by Yam and co-workers note SHG from surfactant derivatives such as (54) and (55) deposited in Langmuir-Blodgett (LB) thin films.110-112 For example, the 532 nm SHG from LB films of the stilbazole derivative (55) is ca. 50% more intense than that from films of the structurally related purely organic salt traiw-.lV-methyl-4-[2-(4-octadecyloxyphenyl)ethenyl]pyridinium iodide.112... 

Heterocyclic ring closure of o-hydroxylated or o-acylated styrene, stilbene, and stilbazole derivatives. This group includes miscellaneous methods, the final stage of which involves ring closure of compounds as in Eq. (2). Starting from o-acyloxystilbenes, the reaction provides... 

The L-B films offer some advantages over aqueous-hydrocarbon interfaces of micelles and the related assemblies discussed above in terms of the magnitude of their orienting ability and the ease of interpretation of selectivity in photoreactions conducted in them. Molecules in the films have very little freedom of motion (stiff reaction cavities), their interfaces are very well defined, and therefore the alignment of reactant molecules can be readily expressed in the products. Photodimerization of stilbazole derivatives 62, N-octadecyl-l-(4-pyridyl)-4-(phenyl)-l,3-butadiene, (63), surfactant styrene derivatives 64 and 65, and cinnamic acids have been carried out in L-B films [18, 196-200], In all cases, single isomeric head-head dimers are obtained. Geometric isomerization of olefins has not been observed in competition with photodimerization. Independent of the location of the chromophore (i.e.,... 

Silyl-tethered stilbazole derivatives 349 were synthesized and subjected to intramolecular photocycloaddition in benzene at room temperature to give compounds of type 350 with stereochemistry cis-trans-ris and cis-trans-trans (Equation 66). It was shown that complexation of pyridine-containing stilbazoles 349 with dicarboxylic acid or catechol enhanced both the efficiency and stereoselectivity of the photocycloaddition <2006TL7865>. 

B. NLO Properties of the Stilbazole Derivatives Langmuir-Blodgett Films... 

He et al. [68] examined the effect of adding flexibility to the hydrogen bond acceptor bis-pyridyl units. They attached stilbazole derivatives to either end of differently sized oligo(ethylene oxide) spacers (4) (Fig. 7). Mixing... 

Hydrogen bonding was used to prepare supramolecular ferrocene-containing liquid crystals. The latter were obtained by associating an Fc derivative carrying a carboxylic acid function with either 4,4 -bipyridine 62 or stilbazole derivatives 63 (m, n) " Tetracatenar derivative 62 gave rise to a Colh phase from 66 to 72 °C. The... 

More recently, other versatile hydrogen bonding template was reported by Ramamurthy and co-workers. In this work, thiourea was used as an effective template to direct either bispyridylethylene or stilbazole derivatives. The self-assembly of thiourea forms tapes, whose two type of hydrogen bonding interactions can be established from remaining N-H... 

More reeently, Ramamurthy and co-workers showed the scope of such strategy in a series of stilbazole derivatives grounded with drops of HCl via mechanochemistry. The irradiation exclusively forms ht isomers with... 

Figure 3.9 Phase diagram for the binary mixtures of polymer (4a) and stilbazole derivative (6a), and representation of the hydrogen-bonded complex with the extended rigid core indicated (permission being sought from [14]).

Figure 3.11 (a) Binary phase diagram of 1 1 (acidipyridyl) copolymer-like complexes of polymer (4b) with varying proportions of 2 stilbazole derivatives (6b) (n = 1 and n = 6), as shown in the schematic representation the abscissa represents the variation in terms of mole percent (6b) with n = 6 (permission being sought from [15]). 

Stilbazole derivatives and r-conjugated compounds with a pyridine unit have been extensively studied for a wide range of applications. The grafting of phosphonic acid-derived stilbazole (4-(2-pyridin-4-yl-vinylj-benzylphosphonic acid) on Sn02 or... 

Three-ring systems were also investigated as shown in Figure 48. Being less anisotropic, the clearing points were lower and so for the stilbazole derivatives (43) were mostly in the range 55-80 °C, with only SmA phases being seen. 

Figure 20 (A) A polysiloxane copolymer having benzoic acid sidechains complexed with a mesogenic chiral stilbazole derivative [105], (B) A dipyridil complexed with two monofunctional acids showing Tsn = 166.5°, Tni = 178.5°C. Compare with the open assembly in Fig. 2A (Ref. 7a).

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