Saika Otsubo

Bis(methylthio)tetracenes: Synthesis, Crystal-Packing Structures, and OFET Properties

5,12-Bis(methylthio)tetracene (2) and 5,11-bis(methylthio)tetracene (3) were synthesized. DFT calculations indicate that the HOMO and LUMO energy levels of 2 and 3 are lowered by 0.13-0.24 eV and their HOMO-LUMO energy gaps are reduced by 0.1 eV relative to those of tetracene. X-ray crystallographic data revealed that 2 is arranged as a result of a 1-D slipped-cofacial π-stacking with S-S and S-π interactions, similar to the packing arrangement of 6,13-bis(methylthio)pentacene (1), whereas 3 exhibits a herringbone packing arrangement without S-S interactions. The OFET devices fabricated using spin-coated films of soluble 1 and 2, with a bottom-contact device configuration, exhibited hole mobilities as high as 1.3 × 10(-2) and 4.0 × 10(-2) cm(2) V(-1) s(-1) with current on/off ratios of over 10(5) and 10(4), respectively.

Tetrabenzodiazaporphyrin: the semiconducting hybrid of phthalocyanine and tetrabenzoporphyrin

Bicyclo[2.2.2]octadiene(BCOD)-fused diazaporphyrin was synthesized by the reaction of BCOD-fused dipyrromethane with sodium nitrite in acetic acid/ethanol in the presence of copper(II) acetylacetonate. This soluble precursor was converted into the semiconducting thin film of (tetrabenzodiazaporphyrinato)copper(II) by heating after fabrication via spin-coating.