Charge‐Transfer in Panchromatic Porphyrin‐Tetracyanobuta‐1,3‐Diene‐Donor Conjugates: Switching the Role of Porphyrin in the Charge Separation Process
Charge‐Transfer in Panchromatic Porphyrin‐Tetracyanobuta‐1,3‐Diene‐Donor Conjugates: Switching the Role of Porphyrin in the Charge Separation Process
复制标题
全色卟啉中的电荷转移-四氰基丁-1,3-二烯-供体结合物：切换卟啉在电荷分离过程中的作用
DOI：
10.1002/chem.202102865
复制
发表时间：
2021
期刊：
影响因子：
--
通讯作者：
D'Souza, Francis
中科院分区：
文献类型：
--
作者：
Sekaran, Bijesh;Dawson, Andrew;Jang, Youngwoo;MohanSingh, Kusum V.;Misra, Rajneesh;D'Souza, Francis
使用环加成-逆电环化反应的组合，游离碱和锌卟啉（H2 P和ZnP）在其β-吡咯位置上被强电荷转移络合物修饰，即，四氰基丁-1，3-二烯（TCBD）-吩噻嗪（3和4）或TCBD-苯胺（7和8），新型推拉系统。这些化合物（MP-供体和MP-TCBD-供体）的物理化学性质已经使用一系列电化学，光谱电化学，DFT以及稳态和时间分辨光谱技术进行了研究。卟啉和直接连接到卟啉π系统的吸电子TCBD之间的基态电荷转移相互作用将吸收特征很好地扩展到近红外区域。为了使光事件可视化，在自由能计算的帮助下建立了能级图。将卟啉的作用从最初的电子受体转变为电子供体是可能的。发生的光致电荷分离已建立了补充瞬态吸收光谱研究，然后全球和目标数据分析。已经可以建立在H2 P衍生的缀合物中比ZnP衍生的缀合物更好的电荷稳定性，以及在吩噻嗪衍生的缀合物中比苯胺衍生的缀合物更好的电荷稳定性。这些发现突出了卟啉和第二电子供体的性质在控制紧密定位的供体-受体缀合物中的基态和激发态电荷转移事件中的重要性。
Using a combination of cycloaddition‐retroelectrocyclization reaction, free‐base and zinc porphyrins (H2P and ZnP) are decorated at their β‐pyrrole positions with strong charge transfer complexes, viz., tetracyanobuta‐1,3‐diene (TCBD)‐phenothiazine (3and4) or TCBD‐aniline (7and8), novel class of push‐pull systems. The physico‐chemical properties of these compounds (MP‐Donor and MP‐TCBD‐Donor) have been investigated using a range of electrochemical, spectroelectrochemical, DFT as well as steady‐state and time‐resolved spectroscopic techniques. Ground‐state charge transfer interactions between the porphyrin and the electron‐withdrawing TCBD directly attached to the porphyrin π‐system extended the absorption features well into the near‐infrared region. To visualize the photo‐events, energy level diagrams with the help of free‐energy calculations have been established. Switching the role of porphyrin from the initial electron acceptor to electron donor was possible to envision. Occurrence of photoinduced charge separation has been established by complementary transient absorption spectral studies followed by global and target data analyses. Better charge stabilization in H2P derived over ZnP derived conjugates, and in phenothiazine derived over aniline derived conjugates has been possible to establish. These findings highlight the importance of the nature of porphyrins and second electron donor in governing the ground and excited state charge transfer events in closely positioned donor‐acceptor conjugates.