Yutaka Ie

We have designed and synthesized a pyridine-based tripodal anchor unit to construct a single-molecule junction with a gold electrode. The advantage of tripodal anchoring to a gold surface was unambiguously demonstrated by cyclic voltammetry measurements. X-ray photoelectron spectroscopy measurements indicated that the π orbital of pyridine contributes to the physical adsorption of the tripodal anchor unit to the gold surface. The conductance of a single-molecule junction that consists of the tri

A series of oligothiophenes containing difluorodioxocyclopentene-annelated thiophene units was synthesized, and their electronic properties and structures were investigated by spectroscopic and electrochemical measurements and X-ray analyses. The oligothiophenes having the terminal difluorodioxocyclopentene annelations showed n-type semiconducting behavior on FET devices, and the quaterthiophene revealed field-effect electron mobility as high as 1.3 x 10(-2) cm2 V(-1) s(-1).

Abstract An electronegative conjugated compound composed of a newly designed carbonyl‐bridged bithiazole unit and trifluoroacetyl terminal groups is synthesized as a candidate for air‐stable n‐type organic field‐effect transistor (OFET) materials. Cyclic voltammetry measurements reveal that carbonyl‐bridging contributes both to lowering the lowest unoccupied molecular orbital energy level and to stabilizing the anionic species. X‐ray crystallographic analysis of the compound shows a planar molec

The ruthenium-catalyzed carbonylation at a C-H bond in the benzene ring of a 2-phenyloxazoline is described. The reaction of 2-phenyloxazolines with CO and ethylene in toluene in the presence of a catalytic amount of Ru(3)(CO)(12) resulted in propionylation at an ortho C-H bond in the benzene ring. The presence of the oxazoline ring on the benzene ring is essential for the carbonylation to proceed. Other heterocycles, such as oxazine, oxazole, and thiazoline rings, also served as acceptable dire

The synthesis of difluoromethylene-bridged bithiophene and its oligothiophenes are reported. The spectroscopic and electrochemical measurement as well as X-ray analyses unambiguously revealed that the difluoromethylene bridge largely contributes to keeping planarity between the thiophene rings and lowering the LUMO level. The perfluorohexyl-substituted quaterthiophene derivatives showed n-type semiconducting behavior with field-effect electron mobilities up to 0.018 cm2 V-1 s-1.

New donor–acceptor-type copolymers containing dioxocycloalkene-annelated thiophenes as electron-accepting units have been designed and synthesized for application to p-type organic semiconducting materials in organic photovoltaics. The investigation of their photophysical and electrochemical properties revealed that these copolymers possessed low optical bandgaps (from 1.63 to 1.92 eV) and low-lying HOMO energy levels (from −5.41 to −5.33 eV). Organic field-effect transistor measurements reveale

Y. Ie and G. C. Fu, Chem. Commun., 2000, 119 DOI: 10.1039/A908625K

Abstract Controlling the energetics and backbone order of semiconducting polymers is essential for the performance improvement of polymer‐based solar cells. The use of fluorine as the substituent for the backbone is known to effectively deepen the molecular orbital energy levels and coplanarize the backbone by noncovalent interactions with sulfur of the thiophene ring. In this work, novel semiconducting polymers are designed and synthesized based on difluoronaphthobisthiadiazole (FNTz) as a new

A series of oligothiophenes covered with tert-butyldiphenylsilyl (TBDPS) groups was synthesized, and the spectroscopic measurements and X-ray analyses revealed that the oligothiophene backbone is completely encapsulated by bulky TBDPS groups.

4,9-Dihydro-s-indaceno[1,2-b:5,6-b′]dithiazole-4,9-dione (IDD) was designed as a novel electronegative unit, and the π-conjugated compound (2C-TzPhTz) containing it was synthesized as a candidate for air-stable n-type organic field-effect transistor (OFET) materials. Cyclic voltammetry measurements revealed that the IDD unit contributes to lowering the lowest unoccupied molecular orbital (LUMO) energy level. X-ray crystallographic analysis of 2C-TzPhTz showed an almost planar molecular geometry

Bis(dicyanomethylene)-substituted quinoidal π-conjugated systems containing a benzo[<italic>c</italic>]thiophene unit have been investigated for application as n-type semiconductors.

[Structure: see text] The synthesis of hexafluorocyclopenta[c]thiophene and its based oligothiophenes is described. The effectiveness of a hexafluorocyclopentene unit to lower the LUMO level without disturbing the effective conjugation could be unambiguously clarified by spectroscopic measurements and X-ray analysis.

Molecule-metal junctions are inevitable for the realization of single-molecule electronics. In this study, we developed new tripodal anchors with electron-rich aromatic rings to achieve robust contact with gold electrodes, an effective hybridization of the π orbital with gold electrodes (π channel), and hole transport through π-channel hybridization. Cyclic voltammetry and X-ray photoelectron spectroscopy measurements of the monolayers indicated that the thiophene-based tripodal molecule exhibit

A series of new π-conjugated systems bearing arenedithiocarboxyimides (dithioimides) as electron-accepting terminal units were prepared utilizing thionation of the imide compounds in the final step of the synthesis. The thermal properties of the dithioimide compounds demonstrated that they had a weak crystallization nature, and their photophysical and electrochemical properties were significantly different from those of their imide analogs. As a result, the dithioimide compounds had narrower hig

Abstract The syntheses of perfluoroalkyl-annelated conjugated units: hexafluorocyclopenta[ c ]thiophene, 4,4-difluoro-4 H -cyclopenta[2,1- b :3,4- b ']dithiophene, and 6,6,12,12-tetrafluoroindeno[3,2- b ]fluorine, and these-containing oligomers have been accomplished. The annelation of the perfluoroalkyl groups effectively lowers the lowest unoccupied molecular orbitral (LUMO) energy levels without disrupting the effective conjugation of the backbones, which was unambiguously clarified by spectr