Premium
Functionalised Oligoenes with Unusual Topologies: Synthesis, Electrochemistry and Structural Studies on Redox‐Active [3]‐ and [4]‐Dendralenes
Author(s) -
Bryce Martin R.,
Coffin Malcolm A.,
Skabara Peter J.,
Moore Adrian J.,
Batsanov Andrei S.,
Howard Judith A. K.
Publication year - 2000
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(20000602)6:11<1955::aid-chem1955>3.0.co;2-b
Subject(s) - dication , dihedral angle , chemistry , conjugated system , ring (chemistry) , ferrocene , cyclopentadienyl complex , molecule , redox , electrochemistry , crystallography , crystal structure , stereochemistry , photochemistry , hydrogen bond , organic chemistry , polymer , catalysis , electrode
New [3]‐ and [4]‐dendralenes bearing electron‐donor 1,3‐dithiole and ferrocene substituents have been synthesised. Compounds 8, 15 and 17 have been characterised by single‐crystal X‐ray diffraction. Two of the dithiole rings of 8 are conjugated (dihedral angle 9°), while the third dithiole ring is almost orthogonal to this plane, and hence its π‐electron system is isolated. For the dendralene precursor molecule 15 , the substituted cyclopentadienyl ring, two C=C bonds and fused dithiole and dithiine rings comprise an extended π‐conjugated system. In molecule 17 the potential conjugation path C(6)C(3)C(4)C(5)‐C 5 H 5 is distorted by an 8° twist around the C(3)−C(4) bond and a 7° twist around the C(5)−C(21) bond, and the delocalisation along the chain is insignificant. Solution electrochemical data demonstrate that the dendralenes are strong π‐electron donors, which give rise to dication, radical trication or tetracation species. Spectroelectrochemical studies on compounds 7 and 10 suggest that the radical species are situated within the linear 1,2‐ethylenediylidene moieties and that a conformational change may occur at the dication redox stage. UV/Vis spectroscopic data are consistent with poor cross‐conjugation in these systems.