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Synthesis, structure, and photoreactions of fluorinated 2,11‐diaza[3 2 ]paracyclophane: Photochemical formation of cage‐diene type benzene dimer
Author(s) -
Okamoto Hideki,
Kozai Tetsuya,
Okabayashi Zenji,
Shinmyozu Teruo,
Ota Hiromi,
Amimoto Kiichi,
Satake Kyosuke
Publication year - 2017
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/poc.3726
Subject(s) - chemistry , diene , dimer , benzene , isomerization , cycloaddition , intramolecular force , derivative (finance) , photochemistry , cage , crystal structure , medicinal chemistry , stereochemistry , crystallography , catalysis , organic chemistry , natural rubber , mathematics , combinatorics , financial economics , economics
An octafluorinated 2,11‐diaza[3 2 ]paracyclophane derivative 12 was prepared, and its photochemical reaction was investigated. Upon irradiation at 300 nm, the fluorinated azacyclophane 12 underwent efficient photodimerization of the benzene cores to afford the corresponding photoisomer 13 , which possessed cage diene benzene dimer structure (pentacyclo[6.4.0.0. 2,7 0. 3,12 0 6,9 ]dodeca‐4,10‐diene skeleton). The cage diene structure was established by single‐crystal X‐ray diffraction analysis. The cage diene 13 thermally isomerized to a syn ‐ o , o ′‐dibenzene isomer 22 . The activation parameters for the thermal isomerization were determined to be E a = 121 kJ mol −1 , ΔH ≠ = 118 kJ mol −1 , ΔS ≠ (293 K) = 22 J mol −1 K −1 , and ΔG ≠ (293 K) = 111 kJ mol −1 . It was revealed that, by photoirradiation at 300 nm, the syn ‐ o , o ′‐dibenzene isomer 22 underwent facile intramolecular [π4s + π4s] cycloaddition to reproduce the cage diene isomer 13 .