Efficient synthesis of n-conjugated organic molecules utilizing cross-coupling reactions and application to electronic devices

The development of efficient synthetic methods of n-conjugated compounds by means of cross - coupling reactions are reported. Tetraarylethenes with four different substituents are synthetic targets. The Pt-catalyzed addition of diboron to alkynylsilanes to yield 1 - a r y l - 1-silyl-2,2-dibo-rylethenes with perfect stereoselectivity. Step by step chemoselective Suzuki-Miyaura couplings with aryl halides were performed to give a triarylsilylethene with perfect chemoselectivity. The silyl group was transformed to the aryl group with desilybromination, followed by Suzuki-Miyaura coupling, leading to the successful synthesis of the desired tetraarylated olein. On the other hand, novel and versatile methods for the synthesis of various phenacene and thienophenacene deriva¬ tives by cross-coupling reactions were elucidated for application to organic ield-effect transistors (OFETs) and organic photovoltaics (OPVs). As one of representative phenacenes, picene is a polycyclic aromatic hydrocarbon consisting of i v e fused benzene rings with a W-shape structure, which exhibits high hole mobility. We successfully found the synthetic route of various substituted picenes. In addition, the synthesis of phenanthro[1,2-b-8,7-6']dithiophene (PDT) was achieved by replacing two terminal phenyl rings in picene with thiophene rings. The fabricated OFET devices based on C1 2-PDT-2 displayed a quite high mobility of up to 5.6cm2 V " 1 s - ¹ . In regard to OPV devices, PDT-fluorinated benzothiadiazole (BT) polymers possessing alkyl side chains showed the highest power conversion efficiencies (PCE) of 9.0%.