Modeling the framework stability and catalytic activity of pure and transition metal-doped zeotypes

We present a thorough computational study of transition metal-doped zeolite and aluminophosphate (AlPO) frameworks. The structural and electronic chemistry of the dopants is examined with ab initio quantum mechanical calculations, and the results correlated with the Brønsted and Lewis acid strength, and with the redox potential of the dopant ions in the framework. The energetics of doping is provided, and is employed to analyze the mode of dopant incorporation, and its site ordering in the microporous framework. In total, 23 dopant ions are examined in the isostructural framework of chabasite and AlPO-34. These cover most of the isomorphous framework replacements known to occur experimentally, but also framework replacements that have not yet been achieved. In this case, ab initio modeling techniques are employed in a predictive way. Finally, we present a computational study of the alkene epoxidation on titanosilicates, that covers the whole catalytic cycle.     

Creating Employment Opportunities for People with Mental Health Problems: A Feasibility Study for New Initiatives

This paper describes a feasibility study for the development of a network of employment services for people with mental health problems (and others) who are unemployed. It highlights the problems of using debate-orientated, soft OR methods when there are difficulties of open communication between different interest groups. In this case, the interest groups were clients and professionals in the mental health system. To bypass these difficulties, a series of confidential interviews was conducted with stakeholders. The issue of who was to be interviewed was resolved through a rolling programme of recommendations, where each interviewee recommended others until most of the people being recommended were people who had already been seen. This approach allowed for the involvement of many people and agencies who the researchers did not initially suspect might be stakeholders. Having conducted the interviews, the researchers then produced a design in the form of an ‘expert’ report. Although they had serious reservations about taking such an approach instead of simply supporting the expertise of already identified stakeholders, it turned out, upon reflection, that they had made the right decision. The ‘expert’ appoach allowed the views of service users to be taken into account. Also, the rolling programme of recommendations used to determine who should be interviewed actually uncovered hitherto ‘hidden’ stakeholders who were crucial to the success or failure of the whole project.     

Separation and Turbulence Control in Biomimetic Flows

The study of the flow around live marine animals and robotic mechanisms which emulate fish motion has revealed a number of mechanisms of flow control, optimised through evolution to minimize the energy required for steady and unsteady motion underwater. We outline some of the mechanisms used to (a) eliminate separation, (b) reduce turbulence, and (c) extract energy from oncoming vortical flows.     

Application of the copper catalysed N-arylation of amidines in the synthesis of analogues of the chemical tool, blebbistatin

A robust protocol for the CuI-catalysed arylation of amidines is presented. Whilst the initially identified conditions were useful for benzamidine-derived substrates, difficulties were encountered with more complex substrates. This problem was overcome following a change in ligand type, enabling the synthesis of analogues of the chemical tool, blebbistatin.     

Clickable polyglycerol hyperbranched polymers and their application to gold nanoparticles and acid-labile nanocarriers

A one-step, large-scale preparation of alkyne-containing hyper-branched polyglycerols (HPG) is reported. The HPGs undergo click reactions to organic azides allowing a range of applications.     

Dual photochemistry of anthracene-9,10-endoperoxide studied by femtosecond spectroscopy

The dual photochemistry of anthracene-9,10-endoperoxide (APO) was investigated in a fs UV pump-supercontinuum probe experiment, along with anthracene (AC) and anthraquinone (AQ) for comparison. Excitation of APO at 282 nm leads to 100% product formation by two competing photoreaction channels. Cycloreversion generates with a ～25% quantum yield (QY) (1)O(2) and AC vibrationally excited in the singlet electronic ground state (hot AC). 1-2% of the AC is generated in the lowest triplet state, but no AC is generated in electronically excited singlet states. Generation and cooling of hot AC are modeled using solution phase and broadened gas-phase AC absorption spectra at various temperatures. Results indicate ultrafast generation of hot AC within 3 ps, much faster than reported before for derivatives of anthracene endoperoxide, and subsequent cooling with an 18 ps time constant. The homolytic O-O cleavage pathway generates a biradical, which converts into electronically excited diepoxide (DE). Our data indicate a 1.5 ps time constant that we tentatively assign to the biradical decay and DE formation. Cooling of DE in this electronically excited state takes place with a ～21 ps time constant. Excitation of AQ at 266 nm is followed by an ultrafast population of the T(1)(nπ*) triplet state of AQ with a time constant of (160 ± 60) fs.     

Time-resolved CIDNP: an NMR way to determine the EPR parameters of elusive radicals

Chemically Induced Dynamic Nuclear Polarization (CIDNP) of the diamagnetic products of radical reactions is exploited for the purpose of determination of the hyperfine coupling constants (HFCCs) of the radical intermediates. A simple proportionality relation between geminate CIDNP of a nucleus and its HFCC at the radical stage is established. The applicability range of this relation is determined: the relation is fulfilled in the case of a large difference in g-factor between the radicals involved and for the situation where the number of magnetic nuclei in the system is sufficiently large. The validity of the relation was confirmed by CIDNP experiments on radical pairs with precisely known HFCCs. Using the proportionality relation we were able to measure the HFCCs in various short-lived radicals of the amino acids histidine and tryptophan and of the S-N-centered cyclic radical of methionine derived from the methionine-glycine dipeptide in aqueous solution.