부산대학교 도서관

The synthesis of two new cruciform structures 3and 4comprising an oligophenylenevinylene OPV and a perpendicular oligoaryl bar – namely an oligophenylene OP 3 and a naphthyl–phenyl–naphthyl system 4 – is reported. The OPV rod consists of two terminal pyridine units, whereas the oligoaryl rod bears two terminal acetylsulfanyl groups as protected anchor groups. The OPV bar was assembled via a Horner–Wadsworth–Emmons reaction, which directly led to the desired E,Eisomers. The perpendicular oligoaryl bars were assembled with a Suzuki reaction using the corresponding boronic acids, which were already fitted with an ethyltrimethylsilane ethylTMS sulfanyl group. In a last step, the ethylTMSprotected sulfur atoms were transprotected to the thioacetyl units. The cruciform structures 3and 4are model compounds to investigate a coordinationinduced singlemolecule switch exploiting the potentialdependant different bonding strengths of the anchor groups to gold. Metal–molecule–metal junctions were formed using a mechanically controllable break junction MCBJ setup. Current traces of molecular junctions were statistically analyzed. Further investigations of model compounds consisting only of the single bar confirm that individual molecules carrying the required function for the switching experiments were trapped between two electrodes and were mainly immobilized via thiol–gold anchor bonds.