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By treating compound (V) with a bisboronic acid derivative it is possible to obtain a polymeric structure.

The method includes three steps: Pd-catalyzed Suzuki—Miyaura reaction, hydrolysis under basic conditions and Cu-catalyzed N-arylation.

The bis(1,3-dithiolium) dication salts 8a–c have been synthesised in three steps (31–51% overall yields) starting from 1,4-bis(bromomethyl)naphthalene, 9,10-bis(chloromethyl)anthracene and 4,4′-bis(chloromethyl)biphenyl, respectively. The bis(halogenomethyl) compounds 5 were converted into the dipiperidiniumbis(dithiocarboxylate) salts 6, which on alkylation with 3-chlorobutane-2-one yielded bis(dithioesters)7; cyclisation of 7 occurred on treatment with concentrated sulphuric acid to give dication salts 8. Dimethyl 1,3-dithiol-2-ylphosphonate 20, dimethyl 4,5-dimethyl-1,3-dithiol-2-ylphosphonate 21 and dimethyl 1,3-selenathiol-2-ylphosphonate 22 were treated with butyllithium in the presence of a range of carbonyl compounds and quinones, e.g., cyclopentanone, cyclohexanone, benzophenone, acetophenone, benzaldehyde, thioxanthen-9-one, anthraquinone, bianthrone and naphthacene-5,12-quinone to yield Wittig–Horner products, e.g., alkenes 26–34 and the anthracenediylidene derivatives 35, 36, 40–43 and 53. Unsymmetrical derivatives 37–39 were prepared in two steps as follows: anthrone reacted with 2-methylthio-1,3-dithiolium iodides 45 and 46 in pyridine-acetic acid to yield ketones 48 and 49 which were then treated with the Wittig–Horner reagents 23–25. Cyclic voltammetric data for the new tetrathiafulvalene, selenatrithiafulvalene and diselenadithiafulvalene derivatives 35–43and 53, show that these systems undergo two-electron redox behaviour which is observed as a single wave. Complexes of these donors with electron acceptors, e.g. 7,7,8,8-tetracyano-p-quinodimethane (TCNQ), have been obtained, some of which are organic semiconductors.

A range of TCNQ derivatives,viz. 2,5-dichloro-, 2,5-dibromo-, 2,5-dimethoxy-, 2-methoxycarbonyl- and benzo-TCNQ, and 11,11,12,12-tetracyanonaphtho-2,6-quinodimethane (TNAP), have been efficiently synthesised using 2-chlorcbenzyl thiocyanate as the source of electrophilic cyanide in reactions with the corresponding di(cyanomethyl)benzene or di(cyanomethyl)naphthalcne derivatives. The X-ray crystal structure of 2,5-dibrorno-TCNQ has been determined: the molecule is essentially planar with the dicyanomethylene groups bent away from the adjacent bromine atoms. There are close intermolecular Br ⋯ N contacts in the structure.

2-Dimethoxyphosphoryl-5,6-dihydro-1,3-dithiolo[4,5-b][1,4]-2-dithiin (8) and 2-triphenylphosphonio-5,6-dihydro-1,3-dithiolo[4,5-b][1,4]dithiin tetrafluoroborate (9) have been obtained in four steps from 4,5-ethylenedithio-1,3-dithiole-2-thione (4) (ca. 75% overall yield). Deprotonation of (8) and (9) yields the corresponding carbanion (10) and ylide (11) which have been trapped in good yield with glyoxal, cyclopentanone and anthraquinone to afford ethylenedithio-1,3-dithiafulvalenes

The efficient synthesis of three new vinylogous derivatives 6–8 of bis(ethylenedithio)tetrathiafulvalene (BEDT–TTF) is described; cyclic voltammetry establishes that the new donors have significantly lower solution oxidation potentials than that of BEDT–TTF, and the single crystal X-ray structure of compound 8 is described.

Monolithiation of tetrathiafulvalene (2-(1,3-dithiol-2-ylidene)-1,3-dithiole, TTF) followed by reaction with the appropriate p-toluenesulphonyl halide yields monochloro-, monobromo- and monoiodo-TTF (34-48 % yield); tetrachloro-TTF is obtained in 30 % yield by tetralithiation of TTF followed by addition of p-toluenesulphonyl chloride. Cyclic voltammetric data establish that the oxidation potential of TTF is significantly increased upon halogenation.

The efficient synthesis of a range of novel 1,4,2-dithiazine derivatives by ring expansion of the corresponding 1,3-dithiolium cations in the presence of iodine and aqueous ammonia is reported; the eight π-electron 1,4,2-dithiazine ring is folded about the S ⋯ S axis, as shown by single crystal X-ray analysis, and the heterocycle is electrochemically oxidised to yield, sequentially, the radical cation and dication species.

The synthesis and solution electrochemistry of ten new ethanediylidene-2,2′-bis(1,3-dithiole) derivatives (7)–(16) is described; charge-transfer complexes have been obtained with tetracyano- p -quinodimethane (TCNQ).

A range of derivatives of the 8 π-electron 1,4,2-dithiazine system, viz. compounds 11a–d and 19–24, have been synthesised by ring expansion of the corresponding 1,3-dithiolium salts 8a–d and 13–18, respectively, using a mixture of iodine and aqueous ammonia at room temperature. A mechanism is proposed for the reaction. Competing reaction of compound 14 yields the imine 26 as a minor product. Single crystal X-ray analyses of compounds 11a and 23 reveal that the 1,4,2-dithiazine ring adopts a boat conformation with fold angles about the S ⋯ S axis of 50 and 48°, respectively. The 1,4,2-dithiazine heterocycle is oxidised electrochemically to yield the cation radical at E1½ca. 1.0–1.2 V (versus Ag/AgCl); some derivatives are further oxidised to the dication at E2oxca. 1.4–1.7 V.

Transient thionitrosoarenes, ArN=S, (2) that bear a substituent (CN, Br or Me) ortho to the reactive N=S group have been generated by two entirely different routes and intercepted with dimethylbutadiene to afford mixtures of Diels-Alder and ene adducts, (3) and (4), respectively; the ene adduct predominates for each system.

A range of new bis- and tris-TTF derivatives has been prepared using the TTF-thiolate anion 2 as a key intermediate. Thiolate anion 2 reacts with 2-bromoethanol to yield alcohol 3 from which the bis- and tris-TTF systems 4-7 have been obtained by reaction with the appropriate acid chloride. Subsequent reactions of the malonate anion of dimeric TTF 7 yield derivatives 8-10, which include the amphiphilic system 8

The reaction of mono-lithiated tetrathiafulvalene (TTF) with elemental sulfur or elemental selenium at –78 °C yields the transient species TTF-S– Li+ and TTF-Se– Li+, respectively, which have been trapped with a range of alkyl halides to yield new alkylthio- and alkylseleno-TTF derivatives. Reaction of the TTF-thiolate anion with 2-bromoethanol yields 4-(2-hydroxyethylthio)tetrathiafulvalene which is a particularly versatile building block for the synthesis of a range of new mono-functionalised TTF derivatives containing ether, ester, acrylate, urethane and vinylthio groups in the side chain. Onepot syntheses of ethylenedithio-TTF (EDT-TTF) and ethylenediseleno-TTF (EDS-TTF) from TTF are reported. The structure of EDS-TTF has been determined by single crystal X-ray analysis which reveals dimers with molecular planes orthogonal to each other.

The synthesis and solution redox properties of several covalently attached ferrocene and tetrathiafulvalene units are reported, together with the X-ray crystal structure of a 1,1′-bis(1,3-dithiole-2-ylidene)-substituted ferrocene derivative.

Langmuir-Blodgett (LB) films of 1-tert-butyl-1,9-dihydrofullerene-60 are shown to undergo well defined multistage electrochemical reductions to yield the trianion species, with the first two redox waves stable to recycling; these data contrast with those for LB films of the parent system C60.

A range of alkylthionitroso and arylthionitroso compounds have been generated by thermal fragmentation of N-trimethylsilyl-N-chlorothioalkyl(aryl)amine precursors, and intercepted by reaction with dimethylbutadiene to afford Diels-Alder and ene adducts.

5,6- Dimethyl-3-(2-thienyl)-1,4,2-dithiazine 6, and 3,3′-(meta- and para-phenylene)bis(5,6-dimethyl-1,4,2-dithiazines)10 and 12 have been synthesised, by reaction of the corresponding 1,3dithiolium or bis(1,3-dithiolium) salts, 5, 9 and 11, with a mixture of iodine and aqueous ammonia. A range of the 1,4,2-dithiazine derivatives have been desulfurised to yield isothiazoles upon thermolysis in refluxing toluene. Photolysis of the 1,4,2-dithiazines in the presence of dimethyl acetylenedicarboxylate, tetracyanoethylene and norbornene gives Diels–Alder adducts of the intermediate 1,2-dithiones, and nitrile fragments. Grignard reagents react at S-1 of the 1,4,2-dithiazines, fragmenting the ring to afford nitrite and 1,2-dithioethene moieties. The 1,2,3-dithiazine derivatives 28 and 31 have been isolated from the reaction of the 1,2-dithiolium salts with a mixture of iodine and ammonia; desulfurisation of the 1,2,3-dithiazines occurs readily at room temperature to yield isothiazoles.

Strong intramolecular charge-transfer which occurs in fluorenes 2 and 3 from the donor amino group(s) to the acceptor fluorene moiety leading to exceptionally easy rotation around the C(9)C(α) bond has been observed in solution by 1H NMR and UV–VIS spectroscopy; single crystal X-ray analysis of compound 2h shows significant π-bond delocalization along the C(9)–C(14)–N(2) fragment.

1,3-Diselenolium cation salt 1 reacts with ammonia and iodine to afford the novel 1,4,2-diselenazine system 6 (40% yield) which fragments to yield dimethylcyanamide 8 and diselenin 9, presumably via intermediate 1,2-diselenete 7, which is trapped with dimethyl acetylenedicarboxylate to yield the cycloadduct 10.