Photoinduced electron transfer in TCNQ based systems electrochemical, structural and theoretical aspects

2 Photoinduced electron transfer in TCNQ based systems electrochemical, structural and theoretical aspects 

We have prepared a new type of donor-acceptor organic compound in which both components are linked by two heteroatoms (sulphur, oxygen or 

Firstly, we reported the synthesis of 13,13,14,14-tetracyanobenzo[fe]naphto[2,3-e][l,4]dithiin-6,l 1 -qui-nodimethane (72) and 13,13,14,14-tetracyanoben-zo[b]naphto-[2,3-e][l,4]oxathiin-6,ll-quinodimelhane (73) and other methyl-substituted derivatives as novel single-component donor-acceptor compounds [26]. Their syntheses were carried out from the respective quinones by reaction with malononitrile in the presence of titanium tetrachloride and pyridine. The TCNQ derivatives were thus obtained as dark blue, high melting point solids in moderate yields. 

Interestingly, previous attempts to prepare TCNQ derivatives (76) from benzo[h]naphto[2,3-e][l,4]diox-in-6,11-quinones (74) were unsuccessful, leading to a tricyano derivative (75) instead of the expected TCNQ derivative [160]. 

Substitution of sulphur or nitrogen atoms for one or both oxygen atoms in the dioxin-6,11-quinone results in a favoured 1,2-addition of malononitrile to both carbonyl groups. The reaction of quinones with nucleophilic agents has been recently reviewed considering modem mechanistic aspects [161], 

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