Wiley InterScience Backfile Collection 1832-2000
Chemistry and Pharmacology
-The synthesis of 2,6-dialkoxy-9,10-bis(1,3-dithiol-2-ylidene)-9,10-dihydroanthracene derivatives 15 and 16 is described. Solution electrochemistry shows that 15 and 16 display three redox waves, representing the sequential formation of the dication, radical trication and tetracation species in an EqEqEq process. The X-ray crystal structures of neutral compounds 15 and 16 and the charge transfer complex (15)2+(TCNQ-•)2· 2MeCN are reported. The neutral molecules adopt a saddle-like conformation; the bis(1,3-dithiole)benzoquinone system is U-shaped through an ‘accumulating bend’ comprising the boat conformation of the central (quinonoid) ring and folding of both 1,3-dithiole rings. In the complex (15)2+(TCNQ-•)2· 2MeCN the anthracene system is planar and aromatic; the dithiolium cations form a dihedral angle of 78° with the anthracene plane. The TCNQ anion radicals form a stack of dimers with interplanar separations of 3.15 Å within a dimer and 3.50 Å between the dimers. The structure contains unusually short intermolecular S···N contacts [2.865(3) Å].
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