Reekie Tristan A, Sekita Michael, Urner Lorenz M, Bauroth Stefan, Ruhlmann Laurent, Gisselbrecht Jean-Paul, Boudon Corinne, Trapp Nils, Clark Timothy, Guldi Dirk M, Diederich François
Laboratorium für Organische Chemie, ETH Zürich, Vladimir-Prelog-Weg 3, 8093, Zürich, Switzerland.
Department of Chemistry and Pharmacy and, Interdisciplinary Center for Molecular Materials (ICMM), Friedrich-Alexander-University Erlangen-Nuremberg, Egerlandstrasse 3, 91058, Erlangen, Germany.
Chemistry. 2017 May 5;23(26):6357-6369. doi: 10.1002/chem.201700043. Epub 2017 Apr 7.
We report on a series of electron donor-acceptor conjugates incorporating a Zn -porphyrin-based electron donor and a variety of non-conjugated rigid linkers connecting to push-pull chromophores as electron acceptors. The electron acceptors comprize multicyanobutadienes or extended tetracyanoquinodimethane analogues with first reduction potentials ranging from -1.67 to -0.23 V vs. Fc /Fc in CH Cl , which are accessible through a final-step cycloaddition-retroelectrocyclization (CA-RE) reaction. Characterization of the conjugates includes electrochemistry, spectroelectrochemistry, DFT calculations, and photophysical measurements in a range of solvents. The collected data allows for the construction of multiple Marcus curves that consider electron-acceptor strength, linker length, and solvent, with data points extending well into the inverted region. The enhancement of electron-vibration couplings, resulting from the rigid spacers and, in particular, multicyano-groups in the conformationally highly fixed push-pull acceptor chromophores affects the charge-recombination kinetics in the inverted region drastically.
我们报道了一系列电子供体-受体共轭物，其包含基于锌卟啉的电子供体以及连接到作为电子受体的推挽发色团的多种非共轭刚性连接基。电子受体包括多氰基丁二烯或扩展的四氰基喹二甲烷类似物，其在二氯甲烷中相对于二茂铁/二茂铁阳离子的首次还原电位范围为-1.67至-0.23 V，可通过最后一步环加成-逆电环化（CA-RE）反应获得。共轭物的表征包括电化学、光谱电化学、密度泛函理论计算以及在一系列溶剂中的光物理测量。收集到的数据允许构建多条考虑电子受体强度、连接基长度和溶剂的马库斯曲线，数据点很好地延伸到反转区域。由于刚性间隔基，特别是构象高度固定的推挽受体发色团中的多氰基基团导致的电子-振动耦合增强，极大地影响了反转区域中的电荷复合动力学。
