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Electrochemically controlled interactions have been shown to occur between TTF containing dendrimers 1 and 2 and the electron-rich oligomer 3.

Hydrogen bonded interactions are among the most important non-covalent interactions in supramolecular chemistry. The strength, selectivity and directionality inherent in hydrogen bonding processes have allowed the creation of complex and efficient molecular hosts capable of selective binding to a wide variety of complementary guests. Major advances in controlling host-guest complexation have occurred in the last decade, principally through systematic modification of the electrostatic properties and/or geometry of the hosts, thereby fine-tuning the molecular recognition event. More recently, systems have been developed which allow the effectiveness and selectively of hydrogen bonding interactions to be reversibly modulated by an external stimulus, more accurately mimicking biological systems and providing building blocks for the construction of novel advanced materials, sensors and devices. In this review, we highlight some of the methods available for modulating the strength and selectivity of hydrogen bonded interactions in synthetic host-guest systems.

The first example of a redox controlled hydrogen bonded three-pole switch is described, which exploits both electrochemical oxidation and reduction of the host–guest dyad to modulate the intermolecular recognition properties.

Tetralithiation of 2-(1,3-diselenol-2-ylidene)-1,3-diselenole (tetraselenafulvalene, TSF) followed by reaction with 0.8 equivalents of an acid chloride yields monoacyl TSF derivatives. The first amphiphilic TSF derivatives, viz-4-tetradecanoyl-TSF and 4-hexadecanoyl-TSF, are reported. An X-ray crystal structure reveals that the TSF ring system of 4-acetyl-TSF deviates considerably from planarity

The synthesis, electrochemistry and mesogenic properties of novel anthraquinolyl–triphenylenes are described. 1H NMR, UV–vis, solution electrochemistry and molecular modelling studies indicate that an intermolecular charge–transfer interaction occurs between the anthraquinone moiety and the triphenylene nucleus.

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.

Phenanthrenequinone undergoes highly efficient proton transfer processes in the presence of a thiourea-functionalised polystyrene copolymer whereas interactions with a similar benzyl-thiourea monomer show strong redox modulation of the quinone without proton transfer.

Electrochemically tuneable hydrogen bonding interactions are described between a phenyl-urea terminated dendrimer and phenanthrenequinone.

We have demonstrated fluorescence resonance energy transfer facilitated by recognition mediated assembly of quantum dots and a tailor-made fluorescent polymer.

Polymer 4 and its monomeric counterpart 3 exhibit electrochemically tuneable interactions with anthracene polymer 2 and a structurally similar monomer 1 as seen by the variation of the oxidation waves of TTF groups and the fluorescence of the anthracene.

Diaminopyridine dendritic scaffolds encapsulate polymeric flavin via non-covalent interactions and demonstrate isolation of the redox moiety.

A series of poly(N-isopropylacrylamide)s (poly(NIPAM)s) have been synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization from a functionalized chain transfer agent (CTA) bearing either dialkoxynaphthalene or dialkoxyphenylene moieties. After demonstrating the controlled character of the RAFT polymerization in the presence of these CTAs, well-defined functionalized poly(NIPAM)s with low PDIs and similar molecular weights were selected and subjected to lower critical solution temperature (LCST) measurements using UV-vis spectroscopy. We have investigated the complexation of the polymers with the tetracationic cyclophane cyclobis(paraquat-p-phenylene) (CBPQT4+) and specifically the role the counter anion (Cl−, Br−, I−) of the cyclophane has on the LCST. Moreover, we have shown that the addition of a competing end-functionalized naphthalene poly(NIPAM) guest to a (CBPQT4+)–end-functionalized phenylene poly(NIPAM) complex results in the dethreading of the original architecture.

Gold nanoparticles functionalised with a valine-derived formamide have been developed as effective homogenous catalysts for the asymmetric reduction of ketimine 1 with trichlorosilane (or = 84% ee) in toluene. This methodology both simplifies the recovery of the catalyst and its separation from the product, as the nanoparticles can be readily removed and subsequently recycled by precipitation from the reaction mixture.

We describe the role functionality attached to the C(7) position of a family of flavin derivatives has in tuning their redox and recognition properties and the subsequent exploitation of two of these derivatives as a three-component electrochemically controllable molecular switch.

We describe the application of the LCST of a naphthalene-functionalised polyNIPAM derivative as a convenient, tuneable and reversible method to disrupt complex formation with CBPQT(4+) in water.

Three generations of water-soluble flavin dendrons have been synthesized and the role dendrimer generation has on the physical and catalytic properties of these assemblies has been investigated.

We report the synthesis, solid-state and preliminary solution properties of a flavin-based [2]catenane.

We have synthesised a flavin derivative incorporating functionalities that promote intramolecular self-assembly via hydrogen bonding and aromatic interactions.

Monolithiotetrathiafulvalene reacts with the acyl chlorides (IIa) and (IIb), hexadecyl chlorothioformate (IIc), or trimethylsilyl chloride (IId) to produce the monosubstituted tetrathiafulvalenes (IIIa) -(IIId).

We have used mixed monolayer protected gold clusters (MMPCs) to provide flavoenzyme model systems with a high affinity and ability to modulate cofactor reduction potential.

We report the electrochemically tuneable intramolecular hydrogen bonding interactions between a covalently linked flavin-diamidopyridine unit.

We report the electrochemically-tuneable interactions between flavin-functionalised C60 derivatives and a diamidopyridine derivative.

The electrochemically tuneable hydrogen bonding interactions between roseoflavin analogue 2 and apoenzyme mimic 3 are described.

We report the fabrication of flavin-functionalised self-assembled monolayers upon gold electrodes and their subsequent redox modulation via hydrogen bonding to 2,6-diethylamidopyridine.

A stable tetrathiafulvalene (TTF) functionalized self-assembled monolayer has been fabricated from compound 3. The electrochemical adjustment of the guest properties of the TTF moiety of this unit has facilitated the development of surfaces in which the 30 state forms a pseudorotaxane with the electron deficient macrocyclic host cyclobis(paraquat-p-phenylene) 1, and the electrochemically generated dicationic state 32+ forms a pseudorotaxane with the electron rich macrocyclic host 1,5-dinaphtho[38]crown-10 2.

The synthesis and characterisation of the first discotic liquid crystalline tetrathiafulvalenylphthalocyanine is described.

The synthesis and characterisation of the first discotic liquid crystalline derivative of ferrocene are described.

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.

Tetrathiafulvalenyllithium reacts with N-methylisothiocyanate to afford the title compound 3, which is the first example of a neutral tetrathiafulvalene derivative to form a kappa-phase structure.