Nogami, Juntaro; Tanaka, Yusuke; Sugiyama, Haruki; Uekusa, Hidehiro; Muranaka, Atsuya; Uchiyama, Masanobu; Tanaka, Ken published the artcile< Enantioselective Synthesis of Planar Chiral Zigzag-Type Cyclophenylene Belts by Rhodium-Catalyzed Alkyne Cyclotrimerization>, Quality Control of 139139-93-8, the main research area is zigzag cyclophenylene belt enantioselective preparation; rhodium catalyst enantioselective cyclotrimerization heptynyl oxypropynylphenoxyphenylene oligomer; mol crystal structure racemic zigzag cyclophenylene belt; mechanism enantioselectivity cyclotrimerization heptynyl oxypropynylphenoxyphenylene; ring strain calculated zigzag cyclophenylene belt; fluorescence UV visible absorption zigzag cyclophenylene belt; dissymetry factor ECD CPL nonracemic zigzag cyclophenylene belt.
Planar chiral zigzag-type [8] and [12]cyclophenylene belts were prepared enantioselectively by rhodium-catalyzed enantioselective intramol. sequential cyclotrimerizations of a cyclic [oxypropynylbis(heptynyloxy)phenoxybis(heptynyl)phenylene] dimer and trimer. The observed enantioselectivity likely arose from the regioselective formation of a rhodacyclic intermediate from an unsym. triyne unit. The structure of the racemic zigzag [8]cyclophenylene belt was determined by X-ray crystallog.; the homochiral belts mesh with one another to form columns in the solid state, with columns of alternating chiralities. The ring strain of the zigzag [8]cyclophenylene belt was smaller than that of the corresponding armchair-type cycloparaphenylene despite its smaller ring size because of the presence of strain-relieving m-terphenyl moieties. The effect of the number of the benzene rings in the zigzag cyclophenylene belts on their UV/visible absorption and fluorescence was small because of the interruption of conjugation by the m-phenylene moieties, but the effect of bending on the absorption and emission peaks and on the absolute fluorescence quantum yield was significant. Modest anisotropy dissymmetry factors of the electronic CD and CPL spectra were observed for the zigzag [8]cyclophenylene belt.
Journal of the American Chemical Society published new progress about Circular dichroism (electronic). 139139-93-8 belongs to class chiral-phosphine-ligands, and the molecular formula is C44H40P2, Quality Control of 139139-93-8.
Referemce:
Phosphine ligand,
Chiral phosphine ligands in asymmetric synthesis. Molecular structure and absolute configuration of (1,5-cyclooctadiene)-(2S,3S)-2,3-bis(diphenylphosphino)butanerhodium(I) perchlorate tetrahydrofuran solvate