Tetraazacyclophanes by Palladium-Catalyzed Aromatic Amination. Geometrically Defined, Stable, High-Spin Diradicals
摘要:
[GRAPHICS]Neutral tetraazacyclophanes were prepared in a one-step palladium-catalyzed amination reaction, Simple oxidation of these materials creates dication diradicals that are stable at room temperature and that are geometrically well defined. The electronic and magnetic properties of the dications were investigated by CV, UV-vis, and EPR spectroscopy. These spectral data and solution phase magnetic susceptibility measurements indicate high spin ground states in certain media. EPR zero field splitting parameters for the diradical suggest that the distance between the two radical sites can be approximated simply by the distance between alternating nitrogens in the macrocycle.
Tetraazacyclophanes by Palladium-Catalyzed Aromatic Amination. Geometrically Defined, Stable, High-Spin Diradicals
摘要:
[GRAPHICS]Neutral tetraazacyclophanes were prepared in a one-step palladium-catalyzed amination reaction, Simple oxidation of these materials creates dication diradicals that are stable at room temperature and that are geometrically well defined. The electronic and magnetic properties of the dications were investigated by CV, UV-vis, and EPR spectroscopy. These spectral data and solution phase magnetic susceptibility measurements indicate high spin ground states in certain media. EPR zero field splitting parameters for the diradical suggest that the distance between the two radical sites can be approximated simply by the distance between alternating nitrogens in the macrocycle.
Polaron Delocalization in Ladder Macromolecular Systems
作者:X. Z. Yan、J. Pawlas、T. Goodson、J. F. Hartwig
DOI:10.1021/ja050184n
日期:2005.6.1
extensive research that is motivated, in part, by the potential to create optical and electronic devices. We have shown that palladium-catalyzedamination can assemble triarylamine ladder materials with extended structures. Two ladder macromolecules have been prepared in high yields by a series of twelve or sixteen C-N coupling reactions. Studies of the electronic and optical properties of neutral and
Tetraaza[1.1.1.1]<i>m</i>,<i>p</i>,<i>m</i>,<i>p</i>-cyclophane Diradical Dications Revisited: Tuning Spin States by Confronted Arenes
作者:Ryohei Kurata、Daisuke Sakamaki、Akihiro Ito
DOI:10.1021/acs.orglett.7b01229
日期:2017.6.16
Diradical dications of two kinds of alternate-meta pars-linked tetraatacyClophanes:in which p-phyenylene-(1);and 2,10-arithracenylene (2a) moieties,are embedded in their macrodyclic backbones were suecessfully isolated as air-stable salts. The Structures Of I2+ and 2a(2+) were elucidated by X-ray Analysis, and significantly different types of structural deformation led to different spin. density distributions due to the steric demand of the confronted arene,moieties. The singlet triplet energy gaps were determined to be +0.3 kcal mol(-1) (+151 K) and 1.0: kcal mol(-1) (-503 K) by SQUID measurements, indicatirig the triplet ground state for I2+ and the singlet ground. state for 2a(2+).
Tetraazacyclophanes by Palladium-Catalyzed Aromatic Amination. Geometrically Defined, Stable, High-Spin Diradicals
作者:Sheila I. Hauck、K. V. Lakshmi、John F. Hartwig
DOI:10.1021/ol9912276
日期:1999.12.1
[GRAPHICS]Neutral tetraazacyclophanes were prepared in a one-step palladium-catalyzed amination reaction, Simple oxidation of these materials creates dication diradicals that are stable at room temperature and that are geometrically well defined. The electronic and magnetic properties of the dications were investigated by CV, UV-vis, and EPR spectroscopy. These spectral data and solution phase magnetic susceptibility measurements indicate high spin ground states in certain media. EPR zero field splitting parameters for the diradical suggest that the distance between the two radical sites can be approximated simply by the distance between alternating nitrogens in the macrocycle.