Premium
Two‐Dimensional Acetylenic Scaffolding: Extended Donor‐Substituted Perethynylated Dehydroannulenes
Author(s) -
Kivala Milan,
Mitzel Frieder,
Boudon Corinne,
Gisselbrecht JeanPaul,
Seiler Paul,
Gross Maurice,
Diederich François
Publication year - 2006
Publication title -
chemistry – an asian journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.18
H-Index - 106
eISSN - 1861-471X
pISSN - 1861-4728
DOI - 10.1002/asia.200600131
Subject(s) - antiaromaticity , annulene , intramolecular force , cyclic voltammetry , protonation , chemistry , photochemistry , redox , alkyne , electron transfer , chromophore , crystallography , singlet state , medicinal chemistry , computational chemistry , stereochemistry , aromaticity , electrochemistry , inorganic chemistry , organic chemistry , molecule , ion , electrode , physics , atomic physics , excited state , catalysis
Starting from ( Z )‐bis( N , N ‐diisopropylanilino)‐substituted tetraethynylethene (TEE), perethynylated octadehydro[12]‐ and dodecadehydro[18]annulenes were prepared by oxidative Hay coupling. The dodecadehydro[18]annulene with six peripheral N , N ‐diisopropylanilino substituents was characterized by X‐ray crystallography. Elongation of the Z ‐bisdeprotected TEE by Cadiot–Chodkiewicz coupling with 1‐bromo‐2‐(triisopropylsilyl)ethyne provided a Z ‐configured bis(butadiyne), which after alkyne deprotection afforded under Hay coupling conditions N , N ‐diisopropylanilino‐substituted perethynylated hexadecadehydro[20]‐ and tetracosadehydro[30]an‐nulenes. The diisopropylanilino substituents enhance the properties of these unprecedented all‐carbon perimeters in several distinct ways. They ensure their solubility, increase their stability, and importantly, engage in strong intramolecular charge‐transfer interactions with the electron‐accepting all‐carbon cores, resulting in intense, bathochromically shifted charge‐transfer bands in the UV/Vis spectra. The charge‐transfer character of these bands was confirmed by protonation‐neutralization experiments. The redox properties of the new carbon‐rich chromophores were investigated by cyclic voltammetry and rotating disk voltammetry, which indicated different redox behavior for aromatic (4 n +2 π electrons) and antiaromatic (4 n π electrons) dehydroannulenes.