TY - JOUR
T1 - The mechanism of charge-transfer nitration of naphthalene
AU - Kim, Eun K.
AU - Bookman, T. Michael
AU - Kochi, Jay K.
PY - 1992
Y1 - 1992
N2 - Electrophilic (thermal) and charge-transfer (photochemical) nitration of naphthalene are effectively carried out in acetonitrile with various X-substituted N-nitropyridinium salts with X = 4-MeO, H, 4-MeO2C and 2,6-Me2. Quantitative analyses indicate that both processes effect nuclear nitration to afford the same distribution of isomeric α- and β-nitronaphthalenes, together with the production of various amounts of (nitro-pyridine) adducts to naphthalene. Time-resolved (picosecond) spectroscopy identifies the naphthalene cation radical (NAPH.+) as the critical reactive intermediate in charge-transfer nitration. The subsequent disappearance of NAPH.+ occurs by its combination with NO2 to form the isomeric (α/β) Wheland intermediates, which suffer competitive deprotonation (to yield the nitronaphthalenes) and nucleophilic addition (to produce the adducts). The relevance of such a charge-transfer mechanism to naphthalene nitration via the electrophilic (thermal) process is discussed.
AB - Electrophilic (thermal) and charge-transfer (photochemical) nitration of naphthalene are effectively carried out in acetonitrile with various X-substituted N-nitropyridinium salts with X = 4-MeO, H, 4-MeO2C and 2,6-Me2. Quantitative analyses indicate that both processes effect nuclear nitration to afford the same distribution of isomeric α- and β-nitronaphthalenes, together with the production of various amounts of (nitro-pyridine) adducts to naphthalene. Time-resolved (picosecond) spectroscopy identifies the naphthalene cation radical (NAPH.+) as the critical reactive intermediate in charge-transfer nitration. The subsequent disappearance of NAPH.+ occurs by its combination with NO2 to form the isomeric (α/β) Wheland intermediates, which suffer competitive deprotonation (to yield the nitronaphthalenes) and nucleophilic addition (to produce the adducts). The relevance of such a charge-transfer mechanism to naphthalene nitration via the electrophilic (thermal) process is discussed.
UR - http://www.scopus.com/inward/record.url?scp=37049081919&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=37049081919&partnerID=8YFLogxK
U2 - 10.1039/p29920001879
DO - 10.1039/p29920001879
M3 - Article
AN - SCOPUS:37049081919
SP - 1879
EP - 1891
JO - Journal of the Chemical Society, Perkin Transactions 2
JF - Journal of the Chemical Society, Perkin Transactions 2
SN - 1470-1820
IS - 11
ER -