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Photochemistry of the π‐Extended 9,10‐Bis(1,3‐dithiol‐2‐ylidene)‐ 9,10‐dihydroanthracene System: Generation and Characterisation of the Radical Cation, Dication, and Derived Products
Author(s) -
Jones Allison E.,
Christensen Christian A.,
Perepichka Dmitrii F.,
Batsanov Andrei S.,
Beeby Andrew,
Low Paul J.,
Bryce Martin R.,
Parker Anthony W.
Publication year - 2001
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/1521-3765(20010302)7:5<973::aid-chem973>3.0.co;2-#
Subject(s) - dication , dithiol , chemistry , photochemistry , organic chemistry , ion
Flash photolysis of bis[4,5‐di(methylsulfanyl)1,3‐dithiol‐2‐ylidene]‐9,10‐dihydroanthracene ( 1 ) in chloroform leads to formation of the transient radical cation species 1 .+ which has a diagnostic broad absorption band at λ max ≈650 nm. This band decays to half its original intensity over a period of about 80 μs. Species 1 .+ has also been characterised by resonance Raman spectroscopy. In degassed solution 1 .+ disproportionates to give the dication 1 2+ , whereas in aerated solutions the photodegradation product is the 10‐[4,5‐di(methylsulfanyl)1,3‐dithiol‐2‐ylidene]anthracene‐9(10 H )one ( 2 ). The dication 1 2+ has been characterised by a spectroelectrochemical study [ λ max (CH 2 Cl 2 )=377, 392, 419, 479 nm] and by an X‐ray crystal structure of the salt 1 2+ (ClO 4 − ) 2 , which was obtained by electrocrystallisation. The planar anthracene and 1,3‐dithiolium rings in the dication form a dihedral angle of 77.2°; this conformation is strikingly different from the saddle‐shaped structure of neutral 1 reported previously.