Stilbazoles preparation

It has been reported that the best acidic conditions for stilbazole preparation require reaction of picoline with benzaldehyde (1 2 molar equivalents) in acetic anhydride (1 molar equivalent) and acetic acid (1 molar equivalent) with the exclusion of air, whilst in the best basic conditions picoline and benzaldehyde (1 4 molar equivalents) were heated with piperidine (0 2... 

Complexes of these stilbazoles were prepared with some rather simple benzoic acids, such as 4-nitrobenzoic acid, 4-cyanobenzoic acid, and biphenyl-4-carboxyhc acid (Fig. 59) (71). Here, none of the components is liquid crystalline indeed none possesses a flexible chain. Thus one would expect that complexes between them would do nothing but melt. How wrong The data (Fig. 60) reveal that five of the complexes exhibit a nematic phase Remarkably, some these materials have clearing points around 220° C, indicating that the hydrogen bonds are stable to these temperatures. Whoever said hydrogen bonds are not strong ... 

Electropolymerization based on polymerizable vinyl groups has provided a general procedure for the preparation of a variety of films on electrodes (34). Polymeric films have been deposited on Pt, Au, Sn02 Ti02 and vitreous carbon electrodes, although most of the experiments described here have been carried out on Pt. Films have been prepared by electroreductions based on 4-methyl-dine (vbpy), trans-4 -X-stilbazoles, (trans-... 

Electropolymerization of 4-Vinylpyridine Complexes. Investigations of Structural and Electronic Influences on Thin Film Formation. The recent discovery of the reductive polymerization of complexes containing vinylpyridyl ligands (lg), such as Ru -(bpy)2(vpy)22+ has led to the preparation of homogeneous thin layers of very stable electroactive polymers. This method has been extended to 4-vinyl-4 -methyl-2,2 -bipyridine (lg, 21a) and 4-vinyl-l,10-phenanthroline (21b) on both ruthenium and iron. In the following section we discuss our results on thin films derived from the polymerizable ligands BPE and the trans-4 -X-stilbazoles, (4 -X-stilb X - Cl, OMe, CN and H). 

A preparative study of four-center type photopolymerization has established the empirical rule that the crystalline state [2- 2] photodimerization of olefins can be widely extended to the crystalline state photopolymerization of diolefins with a rigid linear structure containing conjugated double bonds separated by the 1,4-position of an aromatic ring, such as stilbazol to DSP, or cinnamic derivatives to I,4-phenylenediacrylic (p-PDA) derivatives (O. During the past eighteen years, a great number of photopolymeric diolefin crystals have been found by the use of this empirical rule (see Table I). 

Phosphonate modification [bottom of 1, 1212]. frans-3-Stilbazole is conveniently prepared by the phosphonate modification of the Wittig reaction 43... 

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... 

The use of hydrogen bonding for mesogenic network formation has been expected for the formation of dynamic mesomorphic states due to the induction of dynamic properties, e.g. reversibility and fast exchange of the H-bonding [108-111]. Supramolecular liquid-crystalline networks have been prepared by the self-assembly of a polyacrylate with a benzoic acid moiety and 4,4 -bipyridine [108]. Complexes 46 form dynamically cross-linked structures obtained by the complexation of a carboxyl-functionalized polyacrylate and a mixture of a stilbazole, which has the single H-bond acceptor, and a bipyridine, which has the two acceptors. 

Sodiiim phenylacetylene, reaction with p-nitrophenyl-propiolyl chloride, 615 Stilbazoles, -carboxy-prep-aration from pyridine aldehydes, 342, 343 stereochemistry, 342, 343 -cyano-preparation from pyridine aldehydes, 343 stereochemistry, 343 stereochemistry of, 348, 349 synthesis, 348, 349 Strecker reaction, preparation of 2-cyanomethylfurans, 666 Strecker synthesis, of pyri-dine-side chain nitriles, 362, 535-538 Streptonigrin, 626 Styryl isocyanates, reaction with ynamines, 639 6-Substituted-2,4-bis(alky 1-... 

Polymer P6BA was prepared by radical polymerization of 4-[(6-acryloxyhexyl)oxybenzoic acid in DMF with AIBN. trans-4-Octyloxy-4 -stilbazole 80Sz was obtained by condensation reaction from 4-octyloxybenzaldehyde and 4-picoline. trans-4-[(4-Methoxybenzoyl)oxy]-4 -stilbazole lOPhSz was prepared from 4-methoxybenzoyl chloride and trans-4-hydroxy-4 -stilbazole which was obtained according to the procedure of Chiang. ... 

Physical cross-linking is easily incorporated into the structures of supramolecular side-chain polymers by using bi- or multifunctional molecules [9,31,93]. The complexation of the functionalized polyacrylates, a stilbazole, and bipyridine molecules form supramolecular side-chain cross-linked polymer 37 (Figure 27) [31,93]. Bis-imidazolyl compounds are also used for such cross-linking [105]. Reversible association-dissociation of the hydrogen bonding leads to the reversible thermal order-disorder transitions, which is an important feature of supramolecular materials. Liquid-crystalline main-chain supramolecular networks have been prepared from multifunctional components [32,123-126], which will be described in Section IV. 

Dinuclear complexes containing W and Pt(iv) centers 967 have been prepared by using a polymethylene bridging ligand.A dimethylplatinum complex with two pyridine ligands containing stilbazole groups 968 has been reported. 

The preparation of substituted diaryl-ethenes, stilbenes, and analogues (e.g., stilbazoles) has been achieved by Wittig [45] or Homer-Emmons reactions [46] of substituted benzaldehydes and benzyl-triphenylphosphonium halides or benzyl-diethoxyphosphonates (see Scheme 4). 4-Methylpicolinium salts [96a,b] or 4-meth-ylpicoline-A-oxides [96c], upon reaction with benzaldehydes under basic conditions lead directly to the corresponding stilbazo-lium salts or stilbazole-TZ-oxides, respectively. As of late, the metal-catalysed cross-... 

A series of unsymmetric rhodium and iridium stilbazoles, 11, was prepared. 

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