Skip to main content

Research Repository

Advanced Search

New strategies and building blocks for functionalised 9,10-bis(1,3-dithiol-2-ylidene)-9,10-dihydroanthracene derivatives, including pyrrolo-annelated derivatives and pi-extended systems with intramolecular charge-transfer

Christensen, C.A.; Bryce, M.R.; Batsanov, A.S.; Becher, J.

Authors

C.A. Christensen

A.S. Batsanov

J. Becher



Abstract

A range of new functionalised 9,10-bis(1,3-dithiol-2-ylidene)-9,10-dihydroanihracene (TTFAQ) derivatives have been synthesised from the key di(halomethyl) building blocks, 10-[4,5-bis(bromomethyl)-1,3-dithiol-2-ylidene]7 anthracene-9(10H)-one 10, 10-[4,5-bis(chloromethyl)-1,3-dithiol-2-ylidene]anthracene-9(10H)-one 11 and 9-[4,5-bis(chloromethyl)-1,3-dithiol-2-ylidene]-10-[4,5-bis(hexylsulfany l)-1,3-dithiol-2-ylidene]-9,10-dihydro-anthracene 18. A Diels-Alder strategy comprising trapping of the transient exocyclic diene 19, which is derived from 18, with 1,4-naphthoquinone leads to the aromatised TTFAQ anthraquinone system 21. Horner-Wadsworth-Emmons olefination of 21 with the anion generated from reagent 22 gave the fused bis(TTFAQ) structure 23. Pyrrolo-annelated derivatives 30-34 have been obtained in a sequence of reactions from compound 10. Monoformylation of the pyrrole ring of 32 and 33 under Vilsmeier conditions gave 35 and 36 which upon reaction with 2,4,5,7-tetranitrofluorene gave the donor-pi-acceptor diads 38 and 39. Cyclic voltammetry (CV) in solution for all the TTFAQ derivatives shows the typical quasi-reversible two-electron oxidation wave of the TTFAQ core at potentials which vary slightly depending on the substituents. For example, the value of E-ox is raised by the electron withdrawing anthraquinone and tetranitrofluorene units of 21 and 38, respectively The CV of the conjugated TTFAQ dimer 23 showed two, two-electron oxidation waves corresponding to the sequential formation of 23(2+) and 23(4+) (DeltaE(ox) = 130 mV) providing evidence for a significant intramolecular electronic interaction, i.e. the dication 23(2+) acts as a conjugated donor-pi-acceptor diad, thereby raising the oxidation potential of its partner TTFAQ unit. Spectroelectrochemical studies on 23 support this explanation. A strong intramolecular charge transfer band at lambda(max) 538 nm is seen in the UV-Vis spectra of the TTFAQ-pi-tetranitrofluorene diads 38 and 39. The X-ray crystal structures are reported for compounds 30, 33 and 34. The pyrrolo-TTFAQ moiety adopts a saddle-shape with the central ring of the dihydroanthracene moiety folded along the C(9)...C(10) vector in each case. Significant intermolecular interactions are observed in the structures.

Citation

Christensen, C., Bryce, M., Batsanov, A., & Becher, J. (2003). New strategies and building blocks for functionalised 9,10-bis(1,3-dithiol-2-ylidene)-9,10-dihydroanthracene derivatives, including pyrrolo-annelated derivatives and pi-extended systems with intramolecular charge-transfer. Organic and Biomolecular Chemistry, 1(3), 511-522

Journal Article Type Article
Publication Date 2003-02
Journal Organic and Biomolecular Chemistry
Print ISSN 1477-0520
Publisher Royal Society of Chemistry
Peer Reviewed Peer Reviewed
Volume 1
Issue 3
Pages 511-522