Solvent effects on charge transfer bands of nitrogen-centered intervalence compounds
Solvent effects on charge transfer bands of nitrogen-centered intervalence compounds
复制标题
DOI：
10.1021/ja003436n
复制
发表时间：
2001-06-20
影响因子：
15
通讯作者：
Teki, Y
中科院分区：
文献类型：
--
作者：
Nelsen, SF;Trieber, DA;Teki, Y
电子转移参数提取的光谱的间隔双（肼）自由基阳离子。将具有通过4-σ键和6-σ键饱和桥双键连接的含2-叔丁基-3-苯基-2，3-二氮杂双环[2.2.2]辛基的带电荷单元的化合物与具有叔丁基异丙基和二苯基取代的带电荷单元的化合物以及具有作为桥的芳族单元的其它化合物进行比较。溶剂效应的研究表明，光学跃迁能（E-OP）不表现为介电连续介质理论预测，但溶剂重组能量可以有效地从振动重组能量中分离，包括线性项的Pekar因子（γ）和Gutmann施主数（DN）在相关的溶剂效应。这些化合物的桥的溶剂化太大而不能忽略，这使得介电连续理论不能正确地预测溶剂对E-op或自由能的影响。
Electron transfer parameters are extracted from the optical spectra of intervalence bis(hydrazine) radical cations. Compounds with 2-tert-butyl-3-phenyl-2,3-diazabicyclo[2.2.2]octyl-containing charge-bearing units that are doubly Linked by 4-sigma -bond and by 6-sigma -bond saturated bridges are compared with ones having tert-butylisopropyl- and diphenyl-substituted charge bearing units and others having the aromatic units functioning as the bridge. Solvent effect studies show that the optical transition energy (E-op) does not behave as dielectric continuum theory predicts but that solvent reorganization energy may be usefully separated from the vibrational reorganization energy by including linear terms in both the Pekar factor (gamma) and the Gutmann donor number (DN) in correlating the solvent effect. Solvation of the bridge for these compounds is too large to ignore, which makes dielectric continuum theory fail to properly predict solvent effects on either E-op or the free energy for comproportionation.