Copolymers of 2-(9H-carbazol-9-yl)ethyl 2-methylacrylate and 4-[5-(4-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]phenyl 2-methylacrylate: correlating hole drift mobility and electronic structure calculations with electroluminescence.

Methacrylate monomers functionalized with pendant carbazole and oxadiazole moieties were copolymerized into random copolymers with varying carbazole/oxadiazole ratios. Specifically, the monomers of 2-(9H-carbazol-9-yl)ethyl 2-methylacrylate (CE) and 4-[5-(4-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]phenyl 2-methylacrylate (tBPOP) were copolymerized in various ratios, and the inherent hole drift mobilities were assessed through time-of-flight techniques. At a field strength of 345 kV/cm, the homopolymer PCE exhibited a hole mobility of 5.9 x 10(-7) cm(2)/V.s, which was approximately twice the value of the technologically important poly(9-vinylcarbazole), which exhibited a value of 2.8 x 10(-7) cm(2)/V.s. The range of hole mobilities in the copolymers varied from 2.4 x 10(-8) cm(2)/V.s for copolymers containing 50 mol % of the carbazole-containing monomer residue to 3.0 x 10(-7) cm(2)/V.s for copolymers that incorporated 88 mol % of the residue. Density functional theory (B3LYP/6-21G*) and optical absorption derived highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energies of CE were -5.39 and -1.94 eV, respectively, while the corresponding oxadiazole monomer (tBPOP) had a HOMO energy of -5.99 eV and a LUMO energy of -2.23 eV. The mean luminous efficiency of coumarin 6 doped single-layer devices constructed from the poly(CE-co-tBPOP) copolymers indicated a relatively flat efficiency of ca. 0.25 cd/A over a wide carbazole mole fraction content of 0.30-0.70.

The electrochemically-tuneable interactions between flavin-functionalised C60 derivatives and 2,6-diethylamidopyridine.

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

Model systems for flavoenzyme activity: site-isolated redox behavior in flavin-functionalized random polystyrene copolymers.

[reaction: see text] A model system has been developed to study the redox behaviors of flavin derivatives appended onto random polystyrene copolymers through "click" chemistry strategies. The results demonstrate that flavin units attached onto polymers exhibit site-isolated redox behaviors, yielding new materials with electrochemically tunable associations (K(a)(ox) = 450 M(-)(1), K(a)(red) = 18,200 M(-)(1)) to complementary diamidopyridine (DAP) functionality.

Model systems for flavoenzyme activity: a tuneable intramolecularly hydrogen bonded flavin-diamidopyridine complex.

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

Molecular recognition in a uradinyl-functionalized stable radical.

Stable radical 2-(6-uradinyl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole-1-oxyl (1) binds to hydrogen-bonding complement 2,6-di(propylamido)pyridine (DAP) in chloroform with Ka=220 M(-1) at 33 degrees C; ESI-MS shows not only 1:DAP complementary dyad formation, but also 1:(DAP)2 formation at higher concentrations of DAP.

Cationic polyhedral oligomeric silsesquioxane (POSS) units as carriers for drug delivery processes.

Quaternary ammonium functionalized polyhedral oligomeric silsesquioxane (OctaAmmonium-POSS) units, widely employed as additives in ceramic and polymeric systems, possess many attributes which make them attractive as biocompatible drug carriers: nanoscale size, three-dimensional functionality, efficient cellular uptake, low toxicity, and high solubility.

Proton transfer versus redox modulation in thiourea-phenanthrenequinone molecular and polymeric complexes.

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.

Model systems for flavoenzyme activity: interplay of hydrogen bonding and aromatic stacking in cofactor redox modulation.

[structure: see text] A model system has been developed to study the synergy between aromatic stacking and hydrogen bonding in the binding of a flavin derivative. The results show that the identity of both the hydrogen bonding and pi-stacking units strongly determine the overall receptor affinity for flavin in both the oxidized and radical anion forms.

Redox modulation of benzene triimides and diimides via noncovalent interactions.

[reaction: see text] Mellitic triimides undergo three sequential one-electron reduction processes whose potentials are significantly lowered in the presence of alkyl thioureas. The two sequential reductions of benzene diimides are similarly stabilized. Calculation of the relative free energy change between the different electronic states of the imide acceptors and their corresponding alkyl thiourea complexes indicates dramatic increases in hydrogen bond strength with increasing acceptor charge density.

Self-assembly of gold nanoparticles through tandem hydrogen bonding and polyoligosilsequioxane (POSS)-POSS recognition processes.

Diaminopyridine-functionalized polyhedral oligomeric silsequioxanes (POSS-DAP) self-assemble with complementary thymine-functionalized Au nanoparticles (Thy-Au) into well-defined spherical aggregates, providing highly structured nanocomposites.

Surface modification via 'lock and key' specific self-assembly of polyhedral oligomeric silsequioxane (POSS) derivatives to modified gold surfaces.

Diaminopyridine (DAP) functionalized POSS derivatives self-assemble on thymine functionalized monolayers on gold surfaces affording hybrid inorganic/organic surfaces.