Synthesis of monodisperse oligo(para-phenyleneethynylene)s using orthogonal protecting groups with different polarity for terminal acetylene units

Monodisperse oligo(para-phenyleneelhynylene)s (oligo-PPEs) were synthesized by a divergent-convergent synthesis starting from 1,4-dihexyl-2-(3-hydroxy prop-1-ynyl)-5-[2- (triisopropylsilyl)ethynyl]benzene and using the Pd/Cu-c atalyzed alkyne-aryl coupling. The groups hydroxymethyl (HOM) and triisopro pylsilyl (TTPS) function as orthogonal protective groups for the acetylene moieties. The polar HOM group shows a strong impact on the chromatographic behaviour of the products and makes the isolation of pure compounds very ea sy. The synthesis was pursued up to the nonamer. The oligoPPEs were fully c haracterised, including absorption and emission spectral data.