Substitution at an octahedral metal centre

vi, 211 leavesThis thesis contains most of the observations, experiments and conclusions resulting from work on the substitution reactions of some octahedral metal complexes. It is divided into four parts. The first chapter is a summary of the effects which are expected to control the rates of inorganic nucleophilic substitutions. The results discussed are those which the author considers are peculiarly inorganic rather than organic; although some overlap is inevitable. It is not intended to be a literature review, and is restricted mainly to octahedral systems. A discussion of the reactions of square planar complexes is not given, nor is any discussion made in regard to electron transfer reactions. The succeeding three chapters have their individual introductions. The intended purpose of these introductions is to give a brief survey of the previous work carried out on the particular problem under investigation. It was hoped by this to indicate clearly that a problem existed, and that it might be solved by the experiments that have been carried out. It was considered that the nature of the chosen topics did not warrant one long-, review type and perhaps perfunctory general introduction at the beginning of the thesis

Di-μ-oxido-bis­[(1,4,8,11-tetra­aza­cyclo­tetra­decane-κ4 N,N′,N′′,N′′′)dimangan­ese(III,IV)] bis­(tetra­phenyl­borate) chloride acetonitrile disolvate

The title compound, [Mn2O2(C10H24N4)2](C24H20B)2Cl·2CH3CN, is a mixed-valent MnIII/MnIV oxide-bridged mangan­ese dimer with one chloride and two tetra­phenyl­borate counter-anions. There are two non-coordinated mol­ecules of acetonitrile in the formula unit. A center of inversion is present between the two metal atoms, and, consequently, there is no distinction between MnIII and MnIV metal centers. In the Mn2O2 core, the Mn—O distances are 1.817 (3) and 1.821 (3) Å. The cyclam ligand is in the cis configuration. The chloride counter-anion resides on a center of symmetry, whereas the tetra­phenyl­borate counter-anion is in a general position. The cyclam ligand is hydrogen bonded to the acetonitrile as well as to the chloride anion. One of the phenyl rings of the anion and the acetonitrile solvent molecule are each disordered over two sets of sites

Crystallographic coincidence of two bridging species in a dinuclear CoIII ethynyl­benzene complex

In the title compound, trans,trans-[μ-(m-phenyl­ene)bis­(ethyne-1,2-di­yl)]bis­[chlorido(1,4,8,11-tetra­aza­cyclo­tetra­deca­ne)cobalt(III)]–trans,trans-[μ-(5-bromo-m-phenyl­ene)bis­(ethyne-1,2-di­yl)]bis­[chlorido(1,4,8,11-tetra­aza­cyclo­tetra­deca­ne)cobalt(III)]–tetra­phenyl­borate–acetone (0.88/0.12/2/4), [Co2(C12H4)Cl2(C10H24N4)2]0.88[Co2(C10H3Br)Cl2(C10H24N4)2]0.12(C24H20B)2·4C3H6O, with the exception of the acetyl­ene and bromine groups, all atomic postitions are the same in the two compounds and are modeled at full occupancy. The CoIII ions are six-coordinate with acetyl­ide and chloride ligands bound to the axial sites and the N atoms from the cyclam rings coordinated at the equatorial positions. N—H⋯O and N—H⋯Cl hydrogen-bonding interactions help to consolidate the crystal packing

2,2′-[4,10-Bis(carb­oxy­meth­yl)-4,10-diaza-1,7-diazo­niacyclo­dodecane-1,7-di­yl]diacetate dihydrate

In the title compound, C16H28N4O8·2H2O, the 12-membered macrocycle has twofold crystallographic symmetry and the asymmetric unit comprises one half-mol­ecule. The four carbox­yl/carboxyl­ate groups reside on the same side of the macrocycle. The mol­ecule is a double zwitterion with two of the carb­oxy­lic acid H atoms transferred to the two N atoms on the opposite sides of the macrocycle, resulting in both N atoms having positive charges and leaving the two resulting carboxyl­ate groups with negative charges. The two remaining carb­oxy­lic acid groups and the carboxyl­ate groups form O—H⋯O hydrogen bonds with the crystal water mol­ecules. The H atoms bound to the N atoms within the macrocyle are engaged in two equivalent hydrogen bonds with the adjacent N atoms

Development and evaluation of an innovative model of inter-professional education focused on asthma medication use

BACKGROUND: Inter-professional learning has been promoted as the solution to many clinical management issues. One such issue is the correct use of asthma inhaler devices. Up to 80% of people with asthma use their inhaler device incorrectly. The implications of this are poor asthma control and quality of life. Correct inhaler technique can be taught, however these educational instructions need to be repeated if correct technique is to be maintained. It is important to maximise the opportunities to deliver this education in primary care. In light of this, it is important to explore how health care providers, in particular pharmacists and general medical practitioners, can work together in delivering inhaler technique education to patients, over time. Therefore, there is a need to develop and evaluate effective inter-professional education, which will address the need to educate patients in the correct use of their inhalers as well as equip health care professionals with skills to engage in collaborative relationships with each other. METHODS: This mixed methods study involves the development and evaluation of three modules of continuing education, Model 1, Model 2 and Model 3. A fourth group, Model 4, acting as a control. Model 1 consists of face-to-face continuing professional education on asthma inhaler technique, aimed at pharmacists, general medical practitioners and their practice nurses. Model 2 is an electronic online continuing education module based on Model 1 principles. Model 3 is also based on asthma inhaler technique education but employs a learning intervention targeting health care professional relationships and is based on sociocultural theory. This study took the form of a parallel group, repeated measure design. Following the completion of continuing professional education, health care professionals recruited people with asthma and followed them up for 6 months. During this period, inhaler device technique training was delivered and data on patient inhaler technique, clinical and humanistic outcomes were collected. Outcomes related to professional collaborative relationships were also measured. DISCUSSION: Challenges presented included the requirement of significant financial resources for development of study materials and limited availability of validated tools to measure health care professional collaboration over time

Conformational study of an artificial metal-dependent regulation site for use in designer proteins

This report describes the dimerisation of glutathione, and by extension, other cysteine-containing peptides or protein fragments, with a 5, 5’-disubstituted-2, 2’-bipyridine or 6, 6”-disubstituted-2, 2’:6’,2”-terpyridine unit. The resulting bipy-GS(2) and terpy-GS(2) were investigated as potential metal ion dependent switches in aqueous solution, and were found to predominantly adopt the transoïd conformation at physiological pH. Metal complexation with Cu(II) and Zn(II) at this pH has been studied by UV/Vis, CD, NMR and ion-mobility mass spectrometry. Zn(II) titrations are consistent with the formation of a 1:1 Zn(II):terpy-GS(2) complex at pH 7.4, but bipy-GS(2) was shown to form both 1:1 and 1:2 complexes with the former being predominant under dilute micromolar conditions. Formation constants for the resulting 1:1 complexes were determined to be log K(M) 6.86 (bipy-GS(2)) and 6.22 (terpy-GS(2)), consistent with a higher affinity for the unconstrained bipyridine, compared to the strained terpyridine. Cu(II) coordination involves the initial formation of 1:1 complexes, followed by 1.5Cu:1bipy-GS(2) and 2Cu:1terpy-GS(2) complexes at micromolar concentrations. Binding constants for formation of the 1:1 complexes (log K(M) 12.5 (bipy-GS(2)); 8.04 and 7.14 (terpy-GS(2))) indicate a higher affinity for Cu(II) than Zn(II). Finally, ion-mobility MS studies detected the free ligands in their protonated form, and were consistent with the formation of two different Cu adducts with different conformations in the gas-phase. We illustrate that the bipyridine and terpyridine dimerisation units can behave like conformational switches in response to Cu/Zn complexation, and propose that in future these can be employed in synthetic biology with larger peptide or protein fragments, to control large scale folding and related biological function

Electrocatalytic urea mineralization in aqueous alkaline medium using NiIIcyclam-modified nanoparticulate TiO2 anodes and its relationship with the simultaneous electrogeneration of H2 on Pt counterelectrodes

NiIIcyclam-modified nanoparticulate TiO2-coated ITO electrodes (ITO/TiO2//NiIIcyclam) were prepared by electropolymerization of NiIIcyclam monomers to TiO2-coated ITO electrodes (ITO/TiO2) to improve electrocatalytic urea CO(NH2)2 oxidation in alkaline aqueous solutions. A high value adding secondary effect was the collection of electrons at Pt cathodes, to simultaneously generate H2 from water reduction. NiIIcyclam-modified ITO electrodes (ITO//NiIIcyclam) were also prepared by electropolymerization of NiIIcyclam monomers to bare ITO electrodes (ITO) for comparison purposes. In the presence of the TiO2 nanoparticles, the urea mineralization on NiIIcyclam coatings was doubled (23.95% – organic carbon removal at 120 min of electrolysis) compared to those without TiO2 nanoparticles (13.02% – organic carbon removal at 120 min of electrolysis). In agreement, the faradaic efficiency for H2 generation at the Pt cathode, electrically connected to an anode having TiO2 nanoparticles (0.99 at 120 min of electrolysis), was also twice as effective than that observed when the same Pt cathode was electrically connected to an anode without TiO2 nanoparticles (0.46 at 120 min of electrolysis). The experimental results indicated that the poisoning of NiII centers (which is caused by an excessive production of CO intermediates during the urea oxidation on both NiIIcyclam-modified anodes) was strongly inhibited in the presence of the nanoparticulate TiO2|NiIIcyclam junction. A final comparison between our results and those reported in selected publications revealed that the NiIIcyclam-modified nanoparticulate TiO2-coated ITO anodes here developed, constitutes a promising electrocatalytic system for performing direct urea mineralization at a relative short electrolysis time. Furthermore, the combination of the following phenomena: (a) effective charge separation on the semiconducting ITO|nanoparticulate TiO2 junctions, (b) remarkable capabilities of the nanoporous TiO2 films for tuning the load of OH� anions demanded by the urea oxidation and, (c) outstanding capabilities of the TiO2 nanoparticles for capturing CO intermediates (at Ti3+ donor sites), successfully promoted the enhancement of the electron external transport to Pt cathodes, and consequently improved the faradaic efficiency associated to the cathodic generation of H2