Regiochemical Effects of Furan Substitution on the Electronic Properties and Solid-State Structure of Partial Fused-Ring Oligothiophenes
摘要:
Oligomers containing the new fused-ring heterocyclic conjugated building block thieno[3,2-b]furan were synthesized, and the effects associated with furan ring substitution into fused-ring oligothiophenes on the electronic properties and solid-state structure were assessed. A series of four ring oligomers which vary in. the degree of furan ring substitution and the regiochemistry of placement were synthesized via Stille cross coupling and oxidative homocoupling strategies. The electronic properties of these oligomers were studied by UV-vis absorption and fluorescence spectroscopies. Substitution of furan rings at the terminal positions yields oligomers with a narrower HOMO-LUMO gap relative to the all-thiophene analogue 2,2'-bithieno[3,2-b]thiophene, and incorporation of furan rings at the interior positions results in oligomers with an increase in rigidity and a higher fluorescence quantum yield. Packing motifs of the oligomers were determined using single crystal X-ray diffraction. In contrast to the herringbone crystal packing observed for nonfused oligothiophenes, oligofurans, thiophene-furan hybrid oligomers, and the all-thiophene analogue 2,2'-bithieno[3,2-b]thiophene, all three regioisomers derived from the dimerization of thieno[3,2-b]furan arrange in a pi-stacked packing motif in the solid state.
Regiochemical Effects of Furan Substitution on the Electronic Properties and Solid-State Structure of Partial Fused-Ring Oligothiophenes
摘要:
Oligomers containing the new fused-ring heterocyclic conjugated building block thieno[3,2-b]furan were synthesized, and the effects associated with furan ring substitution into fused-ring oligothiophenes on the electronic properties and solid-state structure were assessed. A series of four ring oligomers which vary in. the degree of furan ring substitution and the regiochemistry of placement were synthesized via Stille cross coupling and oxidative homocoupling strategies. The electronic properties of these oligomers were studied by UV-vis absorption and fluorescence spectroscopies. Substitution of furan rings at the terminal positions yields oligomers with a narrower HOMO-LUMO gap relative to the all-thiophene analogue 2,2'-bithieno[3,2-b]thiophene, and incorporation of furan rings at the interior positions results in oligomers with an increase in rigidity and a higher fluorescence quantum yield. Packing motifs of the oligomers were determined using single crystal X-ray diffraction. In contrast to the herringbone crystal packing observed for nonfused oligothiophenes, oligofurans, thiophene-furan hybrid oligomers, and the all-thiophene analogue 2,2'-bithieno[3,2-b]thiophene, all three regioisomers derived from the dimerization of thieno[3,2-b]furan arrange in a pi-stacked packing motif in the solid state.
A liquid crystal composition which prevents production of an alignment defect of a liquid crystal compound and also has excellent storage stability during dissolution in a solvent is provided. The liquid crystal composition is suitable for constituting a retardation film capable of favorable circular polarization conversion. The liquid crystal composition includes a polymerizable liquid crystal compound having 3 or more ring structures in the main chain, and aluminum. A content of the aluminum is 1 ppm or more and 170 ppm or less relative to the polymerizable liquid crystal compound.
Facile and Scalable Synthesis of the Fused-Ring Heterocycles Thieno[3,2-<i>b</i>]thiophene and Thieno[3,2-<i>b</i>]furan
作者:John T. Henssler、Adam J. Matzger
DOI:10.1021/ol9010745
日期:2009.7.16
An optimized synthetic methodology which allows for efficient and scalable access to the important fused-ring heterocycle thieno[3,2-b]thiophene and the first reported isolation of thieno[3,2-b]furan Is presented. The properties of thieno[3,2-b]furan were assessed through a detailed analysis of the NMR data and an investigation of the chemical reactivity. Thieno[3,2-b]furan is chemically robust and offers good selectivity toward functionalization at the 2-position via bromination and the 5-position via deprotonation.
LIQUID CRYSTAL COMPOSITION, METHOD OF PRODUCING THE SAME, AND RETARDATION FILM CONSTITUTED FROM THE SAME
申请人:Sumitomo Chemical Company, Limited
公开号:US20170306234A1
公开(公告)日:2017-10-26
A liquid crystal composition is provided containing a polymerizable liquid crystal compound, the composition having high preservation stability when dissolved in a solvent and also having the ability to restrain the development of orientation defects of the liquid crystal compound. A method of producing such a liquid crystal composition is also provided with ease. The liquid crystal composition includes a first polymerizable liquid crystal compound having five or more ring structures on its principal chain and represented by the following formula (A) and a second polymerizable liquid crystal compound having five or more ring structures and represented by the following formula (B).