Engineering a Remarkably Low HOMO–LUMO Gap by Covalent Linkage of a Strong -Donor and a -Acceptor—Tetrathiafulvalene--Polynitrofluorene Diads: Their Amphoteric Redox Behavior, Electron Transfer and Spectroscopic Properties
作者:Dmitrii F. Perepichka、Martin R. Bryce、Andrei S. Batsanov、Eric J. L. McInnes、Jing P. Zhao、Robert D. Farley
DOI:10.1002/1521-3765(20021018)8:20<4656::aid-chem4656>3.0.co;2-1
日期:2002.10.18
incorporating very strong donor and acceptor moieties have been synthesized by condensation of the corresponding R3TTF-sigma-fluoren-9-one diads with malononitrile. Reversible five-step amphoteric redox behavior has been observed with an extremely low HOMO-LUMO gap (approximately 0.3 eV). For compound 14 a strong EPR signal is observed in the solid state, ascribed to intermolecular complexation: a less
新型R3TTF-sigma-A化合物14、16和19(R3TTF =审判-kythtrathiafulvalene,sigma =饱和间隔基,A =聚硝基芴-9-二氰基亚甲基受体)结合了非常强的供体和受体部分,通过缩合相应的化合物R3TTF-sigma-fluoren-9-带有丙二腈的二价单体。已经观察到可逆的五步两性氧化还原行为,其HOMO-LUMO间隙极低(约0.3 eV)。对于化合物14,在固态下观察到很强的EPR信号,这归因于分子间的络合:在溶液中观察到的信号强度较小,相当于大约25。在室温下,有2%的分子以自由基形式存在。在二单元组14和16中的分子内电荷转移表现为在其电子光谱的近红外区域中的强吸收带。光谱电化学数据揭示了两种化合物在可见光和近红外区都有明显的电致变色行为。报告了芴自由基阴离子盐的第一X射线晶体结构,即2,4,5,7-四硝基-9-二氰基亚甲基芴的铜盐(化学计量为1:1)。