Poly dialkyl-PPEs

A mixture of molybdenum hexacarbonyl and 4-chlorophenol is effective in performing al-kyne metathesis of dipropynylated dialkylbenzenes. Alkyne metathesis of these precursors leads to the clean formation of dialkyl poly( paraphenyleneethynylene)s (PPEs) in high yield and with high molecular weights. This facile yet effective access to the PPEs has allowed study of their spectroscopic, structural, and thermal properties. While PPEs have been made before, the dialkyl-PPEs turned out to have particularly interesting optical and liquid-crystalline properties that can be explained in terms of the conformation of the main chains. The PPEs have also been utilized to construct light-emitting diodes and other semiconductor devices. This chapter discusses the interplay of structure, chromicity, and electronic properties of the dialkyl-PPEs. 

This contribution describes the synthesis and properties of organic alkyne-bridged materials that have been made by alkyne metathesis or by Acyclic Diyne Metathesis (AD I MET). This review covers mostly poly(aryleneethynylene)s made at the author s laboratory in South Carolina. A comprehensive review covering poly(aryleneethynylene)s listing important contributions in adjacent areas has appeared [1, 2]. This chapter discusses the synthesis and properties of dialkyl-poly(paraphenyleneethynylene)s (dialkyl-PPEs) in relation to the concept of ADIMET with simple catalyst systems. 

The chromicity of poly(aryleneediynylene)s (PAE) is discussed and described in diis contribution. Four different types of PAEs will be scrutinized a) dialkyl-poly(para-phenylene-ethynylene)s (dialkyl-PPEs), b) dialkoxy-PPEs, c) acceptor substituted PPEs, and d) heteroaryleneethynylenes that contain benzothiadiazole units in their main chain. We will shortly describe their syntheses and then discuss their spectral properties in absorption and emission in solution and in thin films. 

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