Diacetylene aromatic substituted

These observations are consistent with the difficulty that aromatic substituted diacetylenes have in undergoing a topochemical polymerization. The preparation of single crystal polydiacetylenes with aromatic substituents directly attached to the polymer backbone remains a challenge for supramolecular synthesis. 

One of these reactions, namely the oxidation of the cuprous complexes of 2-thienyl and 2- and 3-substituted thienylacetylenes, was studied in this laboratory (80). It has been found that this reaction proceeds in an analogous manner to that in other aromatic series. The yields of the corresponding diacetylenic compounds were high and depended on the oxidizing agent applied. The cuprous complexes of 2-thienylacetylene and 2- and 3-substituted thienylacetylenes are bright yellow substances, stable at room temperature. They could be readily utilized for the determination of thienylacetylenes as well as for cuprous ions. 

Diacetylene monomers with aromatic groups directly bonded to the triple bonds typically do not undergo extensive conversion to polymer (64). More extensive conversions appear to take place in fluorine-substituted diphenyl diacetylenes (65), and this may be an important new vector in PDA research. 

The quadratic NLO active molecules are mostly based on donor-acceptor substituted aromatics benzene, stil-benes, diaryl acetylenes, diacetylenes, and biaryls are commonly used frameworks. In addition to the above materials, many more organic and organometallic compounds were examined by the powder SHG method, or their molecular hyperpolarizabilities were measured using EFISHG/HRS techniques, or both.t >... 

Recently, the Langmuir-Blodgett (LB) technique has been recognized as a useful way of tailoring thin films of molecular thickness. Interest in the LB technique has led to a number of investigations of different types of materials. For example, the classic long-chain fatty acids and alcohols as well as polymerizable molecules, e.g. diacetylenic acids [211-213], aromatic hydrocarbons, e.g. substituted anthracenes [214, 215], TCNQ radical anion salts [216, 217] and charge transfer complexes [218-220] and dye substances can now all be produced as monomolecular layers. 

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