SYNTHESIS AND CHARACTERIZATION OF CARBON-ATOM BRIDGED HETEROCYCLIC POLYMERS OF SPECIFIED CONJUGATION LENGTH .1. NOVEL POLYTERTHIOPHENES

New polymers containing α-(5,5”;-terthiophenediyl) segments separated by an sp3-carbon atom in the main chain were synthesized by acid-catalyzed polymerization of α-terthienyl with aldehydes and characterized. The polyterthiophenes (PTTs) containing CRH bridging groups are soluble in organic solvents. The methylene-bridged polymer, poly[α-(5,5’-terthienyl)methylene] (PTTM), is highly crystalline whereas the benzylidene-bridged and heptylidene-bridged polymers are largely amorphous. The sp3-bridged polyterthiophenes exhibit solution optical absorption maxima from 362 to 379 nm, depending on the side group at the bridge carbon, as expected for the nonconjugated polymers. The new heterocyclic polymers represent the first example of main chain polymers containing conjugated segments of precisely defined π-electronic conjugation length. The polymers are useful precursors to multiblock conjugated copolymers, with alternating aromatic α-(5,5”;-terthienyl) and α-(5,5”-terthienylquinodimethane) segments in the main chain. They are the first examples of organic semiconductor superlattices and also have excellent third-order nonlinear optical properties. © 1990, American Chemical Society. All rights reserved.