Absorption spectra of calix[3]pyrrole analogs as probes for contracted macrocycles
Absorption spectra of calix[3]pyrrole analogs as probes for contracted macrocycles
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杯[3]吡咯类似物作为收缩大环探针的吸收光谱
DOI：
10.1142/s1088424622500754
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发表时间：
2022
影响因子：
1.5
通讯作者：
Inokuma Yasuhide
中科院分区：
文献类型：
--
作者：
Watanabe Keita;Saha Ranajit;Inaba Yuya;Manabe Yumehiro;Yoneda Tomoki;Ide Yuki;Hijikata Yuh;Inokuma Yasuhide
尽管重复单元相同，但与杯[4]-和杯[6]-吡咯类似物相比，杯[3]吡咯及其呋喃衍生物在吸收光谱中表现出红移的最低能量电子跃迁带。我们还观察到 calix[3] 型大环化合物的荧光发射。呋喃/吡咯杂化大环化合物、杯[2]呋喃[1]-吡咯和杯[1]呋喃[2]吡咯的斯托克斯位移根据溶剂极性而显着变化。非共价相互作用（NCI）分析表明，杯[3]吡咯大环中相邻芳环之间的相互作用增强，而杯[4]吡咯中的这种相互作用较弱，其中发色团间距离明显长于杯[3]吡咯。理论分析表明，杯[3]吡咯的红移最低能带对应于HOMO-LUMO跃迁，其能隙比杯[4]吡咯窄。杯[3]吡咯及其相关大环化合物的特征吸收带可用作区分此类大环化合物与表现出几乎相同吸收光谱的高级杯[]吡咯(4)类似物的探针。
Calix[3]pyrrole and its furan derivatives exhibited bathochromically shifted lowest-energy electronic transition bands in their absorption spectra compared with their calix[4]- and calix[6]-pyrrole analogues, despite the repeating units being the same. We also observed fluorescence emission for calix[3]-type macrocycles. The Stokes shift of the furan/pyrrole hybrid macrocycles, calix[2]furan[1]-pyrrole, and calix[1]furan[2]pyrrole, substantially varied depending on the solvent polarity. Non-covalent interaction (NCI) analyses indicated enhanced interactions between neighboring aromatic rings in the calix[3]pyrrole macrocycle, whereas such interactions were weak in calix[4]pyrrole, in which the interchromophore distance is remarkably longer than in calix[3]pyrrole. Theoretical analyses indicated that the red-shifted, lowest-energy bands of calix[3]pyrrole correspond to HOMO–LUMO transitions, the energy gap of which was narrow compared with calix[4]pyrroles. The characteristic absorption bands for calix[3]pyrrole and its related macrocycles are useful as probes for distinguishing such macrocycles from higher calix[]pyrrole (4) analogues that exhibit almost identical absorption spectra.