Gavin O Jones

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Density functional theory (B3LYP) calculations on the transition states for the Huisgen 1,3-dipolar cycloadditions of phenyl azide with acetylene, cyclooctyne, and difluorocyclooctyne are reported. The low activation energy of the cyclooctyne "strain-promoted" cycloaddition (DeltaE = 8.0) compared to the strain-free acetylene cycloaddition (DeltaE = 16.2)(More)
Computational investigations of ligand-directed selectivities in Ullmann-type coupling reactions of methanol and methylamine with iodobenzene by beta-diketone- and 1,10-phenanthroline-ligated Cu(I) complexes are reported. Density functional theory calculations using several functionals were performed on both the nucleophile formation and aryl halide(More)
Nitrogen-based thermoset polymers have many industrial applications (for example, in composites), but are difficult to recycle or rework. We report a simple one-pot, low-temperature polycondensation between paraformaldehyde and 4,4'-oxydianiline (ODA) that forms hemiaminal dynamic covalent networks (HDCNs), which can further cyclize at high temperatures,(More)
The transition states and activation barriers of the 1,3-dipolar cycloadditions of azides with cycloalkynes and cycloalkenes were explored using B3LYP density functional theory (DFT) and spin component scaled SCS-MP2 methods. A survey of benzyl azide cycloadditions to substituted cyclooctynes (OMe, Cl, F, CN) showed that fluorine substitution has the most(More)
A systematic study of acid organocatalysts for the polyaddition of poly(ethylene glycol) to hexamethylene diisocyanate in solution has been performed. Among organic acids evaluated, sulfonic acids were found the most effective for urethane formations even when compared with conventional tin-based catalysts (dibutyltin dilaurate) or(More)
We report efficient syntheses of axially chiral biaryl amides in yields ranging from 80-92%, and with enantioselectivity in the range 88-94% ee employing an asymmetric Suzuki-Miyaura process with Pd(OAc)(2) and KenPhos as ligand. These studies demonstrate that electron-rich and electron-deficient o-halobenzamides can be efficiently coupled with(More)
Combined experimental and computational studies have been performed on the mechanism of formation of poly(hexahydrotriazine) and hemiaminal dynamic covalent network (PHT and HDCN) thermosetting polymers from the reactions of diamines with formaldehyde (Science 2014, 344, 732-735). Results suggest that these polymers are formed by a mechanism involving the(More)
Dynamic covalent materials are stable materials that possess reversible behaviour triggered by stimuli such as light, redox conditions or temperature; whereas supramolecular crosslinks depend on the equilibrium constant and relative concentrations of crosslinks as a function of temperature. The combination of these two reversible chemistries can allow(More)
Aliphatic N-substituted functional eight-membered cyclic carbonates were synthesized from N-substituted diethanolamines by intramolecular cyclization. On the basis of the N-substituent, three major subclasses of carbonate monomers were synthesized (N-aryl, N-alkyl and N-carbamate). Organocatalytic ring opening polymerization (ROP) of eight-membered cyclic(More)
Hemiaminal poly(ethylene glycol) (PEG)-based organogels are formulated in polymerizable solvents. The dynamic-covalent nature of the solvent-H-bonded hemiaminal crosslinks, together with the modification of the crosslinking density of the organogels allows for temperature-dependent viscoelastic control. The shape of uncured gels can be permanently retained(More)