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The time-delayed forwards scattering mechanism recently observed by Althorpe et al. [1] for the H + D2 (v=O, j=O) --? HD(v'=3, j'=O) + D reaction was analysed using the quasi-classical trajectory (QCT) methodology. QCT's were found to reasonably match the quantum snapshots of Althorpe, without the quantum effects. Trajectories were analysed on the fly to investigate the motions of the atoms during the reaction. The dominant reaction mechanism progresses from hard collinear impacts, leading to direct recoil, to glancing impacts. The increased time required for forward scattered trajectories is due to the rotation of the HDD complex. Forwards scattered trajectories display symmetric stretch vibrations of the HDD complex, indicating the presence of a resonance or a quantum bottleneck state. Reactive scattering in the HD(v'=O, j'=O) product channel was found to be governed by two unexpected and dominant new mechanisms, and not by direct recoil as is generally assumed. The new mechanisms involve strong interaction with the conical intersection, an area of the potential energy surface not previously thought to have much effect upon reactive scattering. Initial investigations indicate up to 56% of reactive scattering could be the result of these mechanisms.UV Cavity Ring-Down Spectroscopy of 1, 4-bis(phenylethynyl}benzene The torsional motion of 1, 4 bis(phenylethynyl)benzene (BPEB), a prototype molecular wire, is important for switching in molecular electronics. Cavity ring-down spectroscopy was used to record the torsional spectra of BPEB and 1, 4-bis(phenylethynyl) 2,3,5,6-tetradeuterobenzene in the gas phase. The spectra were modelled using a simple cosine potential. The experimental torsional barrier is very similar to the two ring system, Tolane. It was found that DFT calculations completely overestimate the torsional barrier.IV

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Studies were undertaken to develop a general and practical room temperature protocol for the Buchwald-Hartwig reaction, whereby any aryl halide might be coupled with any N-H moiety using Pd-NHC (AT-Heterocyclic Carbene) catalysis. Efforts using imidazolium salts, where the Pd-NHC complex is formed in situ, resulted in high- yielding reactions of aryl bromides and secondary cyclic amines within 7 h at room temperature, with yields typically in the range of 78-89%. However, only modest yields were obtained with primary amines, secondary acyclic amines and aryl chlorides. Subsequent research with an isolated (NHC)Pd(R-allyl)Cl complex enabled the efficient high-yielding coupling of a wider range of substrates (including aryl chlorides) in as little as 1 min. The commercially-available base lithium hexamethyldisilazide (LHMDS) was found to be key to the success of both protocols. Additionally, intramolecular Heck reactions of benzyl halides with pendant olefin chains have also been performed to afford several seven-membered rings with the use of a commercial laboratory microwave reactor. It was possible to effect the cyclisation of 2-(A-homoallyltosylamino)benzyl chloride and (2-chloromethylbenzyl)malonic acid diethyl ester in yields of 98% and 95% respectively yield within 20 min at 90°C. 2-Homoallyloxybenzyl chloride also underwent reaction in 33% yield at 140°C.

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