The first stopperless TTF containing molecular shuttle is described.

The convergent synthesis of (TTF)(x)(AQ)(y) (TTF = tetrathiafulvalene; AQ = anthraquinone) polyester dendrimers is reported; the molecules undergo clean amphoteric redox behaviour with reversible switching between cationic and anionic states being achieved under electrochemical control; the higher generation system (TTF)(8)(AQ)(4) displays an intradendrimer charge-transfer interaction in solution.

Recent developments in the functionalisation of tetrathiafulvalene (TTF) have enabled TTF units to be covalently linked into macromolecular systems. Convergent syntheses of dendrimers containing TTF units are presented, including a (TTF)(13) system in which TTF units are emplaced at all layers of the structural hierarchy, Thin layer cyclic voltammetry has established that the redox activity of TTF is retained in these macromolecules: sequential oxidation to the radical cation and dication occurs for all the TTF units, yielding highly-charged species in solution. Macromolecules comprising four and eight TTF units built around a phthalocyanine core are also described. These materials present novel architectures with the key property of multielectron redox activity.

The convergent synthesis of a range of aryl ester dendrimers with peripheral tetrathiafulvalene (TTF) units is reported. 4-( Hydroxymethyl)-TTF and 4,5-(2-hydroxymethylpropane-1,3-diyldithio)-TTF have been used as the starting TTF reagents. The core reagents are benzene-1,3,5-tricarbonyl trichloride, terephthaloyl chloride, biphenyl-4-4'-dicarbonyl chloride and 4,4'-oxybis(benzenecarbonyl chloride). Dendrimers comprising up to 12 TTF units have been characterised by elemental analysis, plasma desorption mass spectrometry, H-1 NMR spectroscopy and solution electrochemistry. Cyclic voltammetry (CV) and ultra microelectrode CV studies show that the TTF dendrimers display nearly ideal redox behaviour for the TTF system with no significant interaction between the TTF units. Thin layer cyclic voltammetric studies show that all the TTF units of these systems undergo two, single-electron oxidations. The dendrimers form charge-transfer complexes upon reaction with iodine in solution. Intermolecular interactions of the TTF radical cations are observed in the UV-VIS spectra of some of the oxidised derivatives.

The autopolymerization of styrene, styrenic derivatives, and styrene/(meth)acrylate comonomer mixtures in the presence of stable nitroxide free radicals has been shown to be a ''living'' process. Molecular weight can be controlled by varying the ratio of vinyl monomer to TEMPO and low-polydispersity materials are obtained. Significantly, a de finite incubation period is observed during these polymerizations, and the length of this incubation period increases with increasing amounts of TEMPO. The structures of the in situ generated unimolecular initiators which are formed during this incubation period correspond to those expected from a Mayo mechanism for the autopolymerization of styrene. The isolated and purified adducts, 4 and 5, were shown to be effective unimolecular initiators leading to low-polydispersity, controlled molecular weight polymers.

The complexation of TTF 2 and cyclobis(paraquat-p-phenylene) 1(4+) has been studied by cyclic voltammetry and by spectroelectrochemistry: shifts in the redox potentials for the TTF and the 1(4+) components of 45 and 30 mV, respectively, occur upon complexation. Decomplexation of 2.1(4+). upon oxidation of the TTF unit to the cation radical species has been monitored by spectroelectrochemistry. The complexation/decomplexation process is highly reversible over at least 10 electrochemical cycles, and this process is accompanied by a color change of the solution from dark green (complexed) to pale brown (uncomplexed) which is clearly visible to the naked eye.

Solid-phase organic synthesis is now a prevalent activity in drug discovery. In keeping with this keen interest is the need to develop reliable automated synthesis instrumentation as well as polymeric supports and linkers suitable for the full range of organic synthesis applications. In this paper, we review our activities in the development of new and enabling tools for automated chemical synthesis, including the following: (i) new solid supports such asArgoGel ™ (PS-PEG-based) andArgo-X203 (PS-based); and (ii) theNautilus™2400 system, a fully closed and inert automated chemistry development workstation. Selected chemistry optimization and synthesis examples performed on the Nautilus and new solid supports will be described.

The synthesis of new hyper-branched esters substituted with peripheral tetrathiafulvalene (TTF) groups is described. The use of a 4,4′-diphenylether core provides compounds 12–14 which are shelf-stable and possess good solubility in organic solvents. The oligomeric TTF systems display reversible redox behaviour and semiconducting charge-transfer complexes are formed with tetracyano-p-quinodimethane (TCNQ).

The fundamental requirements for the synthesis of dendrimers and hyperbranched macromolecules is examined. Examples of the divergent and convergent approaches are presented and a comparison of both methods with respect to each other and also the one-step procedure for hyperbranched macromolecules is made. The structural similarities and differences between dendrimers and hyperbranched macromolecules are described and the effect of this on the physical properties of these novel three-dimensional materials is discussed. Finally, a comparison of these materials with linear polymers is examined.

Reversible multielectron transfers are observed in dendrimers containing tetrathiafulvalene (TTF) units. The synthesis of compounds such as 1 will pave the way for investigations into charge-transfer interactions in dendrimers.