Linear organic π-conjugated systems featuring the heavy Group 14 and 15 elements

An overview of the synthesis and properties of linear organic pi-conjugated systems featuring Group 14 and 15 moieties is presented and comparisons made with their better-known hydrocarbon, and nitrogen- and sulfur-containing analogues. The major focus of this review is pi-conjugated systems based on heteroles. The unique electronic structure and nature of siloles and phospholes is examined, highlighting the influence of both the ring substituents and the character of the heteroatom on their photophysical properties. The synthesis of a variety of Group 14 and 15 heterole building blocks suitable for the construction of pi-conjugated systems is presented. The preparation and physical properties of poly- and oligo-(1,1-silole)s and -(2,5-silole)s, oligo-(2,5-phosphole)s and co-oligomers of silole and phosphole blocks with other electron-rich monomer units, all with extended pi-conjugation, are discussed. A brief resume of linear pi-conjugated materials that possess heavy Group 15 elements in the polymer backbone is also presented. (C) 2003 Elsevier B.V. All rights reserved.