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Microporous polymers containing tertiary amine functionality for gas separation membrane fabricationMalpass-Evans, Richard January 2014 (has links)
This research reported in this thesis is based on the synthesis of novel polymers of intrinsic microporosity (PIMs) with the aim of fabricating membranes for gas separation applications. PIMs are composed of rigid and awkwardly-shaped monomeric segments which lack the conformational and rotational freedom needed to pack space efficiently. As a result these polymers display high BET surface areas and display excellent gas permeabilities when solution-cast into films which can be used as gas separation membranes. This thesis describes the synthesis of a range of aromatic diamine, tetraamine, dianhydride, and dicarboxylic acid monomers that conform to the PIM design concept, featuring rigid and contorted architectures. These monomers were then used to synthesise five classes of polymer featuring tertiary amine functionality. Structure-property relationships were established between these polymers and BET surface area measurements. Polymers that displayed adequate film forming properties were also evaluated by our collaborators at The Institute of Membrane Technology for their gas transport parameters. Chapter 6 describes the synthesis of a new class of polymer, Tröger's Base PIMs, featuring a novel polymerisation reaction using chemistry first reported 127 years ago. One of these polymers, DMEA.TB, displays a BET surface area of 1028 m2/g which is the highest recorded for any soluble polymer to date. DMEA.TB places gas permeation data for technologically important gas pairs far over the present Robeson upper bound and has unrivalled potential to separate mixtures containing hydrogen. Chapter 7 deals with quaternerisation and subsequent ion exchange of selected Tröger's Base polymers. Chapter 8 discusses the synthesis of three novel polyimides using highly rigid and contorted ethanoanthracene monomers containing methyl groups that restrict rotation around polymer segments. These polymers display only moderate gas permeation characteristics and possess BET surface areas of up to 694 m2/g. Chapter 9 describes the synthesis of a new class of zwitterionic polysquaraines however, these polymers were shown to be non-porous due to strong ionic/hydrogen bonding. Chapter 10 describes the synthesis of polybenzimidazoles using the PIM design concept but it was found that extensive hydrogen bonding reduces free volume, forming non porous solids. Chapter 11 describes the synthesis of novel polypyrrolones with surface areas of up to 284 m2/g however, film formation was not possible with these materials. Chapter 12 features a brief investigation onto the cross-linking of a Tröger's Base membrane using hydrolysed PIM-1 as polyanionic counterion.
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Soil chemistry of heavy metals under contrasting vegetation coversMacIver, Vicki January 2000 (has links)
The site of study (Pollok Park, Glasgow) features soil under both a coniferous canopy (predominantly Corsican Pine) and a deciduous canopy (predominantly Beech). There is a clear segregation between the two vegetation types which enables a direct comparison into the contribution of canopy type to the heavy metal distribution in soil. Average total metal contents of cores extracted from the two soil types indicated that the deciduous cores have a greater total content of Cr, Cu, Fe, and Mn, and that the two core types contain approximately the same Pb and Zn content. Concentration profiles for Cr, Cu, Fe, Mn, Pb and Zn were established for the two soil types. They showed enrichment of Cr, Cu, Pb and Zn at the surface. Correlation graphs [LOI vs. metal (Cr, Cu, Pb and Zn)] showed there to be a correlation between organic matter content and concentrations of these metals. Molar ratios (carbon : metal [Cr, Cu, Pb and Zn]) were estimated from the correlation graphs. In each case, these were found to be of considerable value, indicating that perhaps these metals are complexed by large organic molecules. Mn and Fe showed no enrichment to the surface and no correlation with organic matter. Speciation studies (Modified BCR sequential extraction procedure and cupric ISE investigations) were conducted on the surface soil (top 5cm), litter and leaves taken from below both vegetation types (deciduous and coniferous) in order to gain an understanding of soil-metal associations. The deciduous and coniferous soils were found to have virtually identical fractionation patterns of Cr, Cu, Pb and Zn (Modified BCR sequential extraction).
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The hydrogenation of nitrobenzene over metal catalystsGelder, Elaine A. January 2005 (has links)
The catalytic hydrogenation of nitrobenzene is an industrially important reaction used in the commercial production of aniline for use in the polyurethane industry. A mechanism for the reaction was first proposed by Haber in 1898 and has been widely accepted despite never being fully delineated. During this study the nitrobenzene hydrogenation reaction was investigated, over a range of metal catalysts, to probe the mechanism of hydrogenation and catalyst deactivation. Initial investigations over Pd/C catalysts revealed the reaction to be sensitive to the solvent and the nature of the carbon support. However more importantly it was shown that the first intermediate in Haber’s scheme, nitrosobenzene, could not act as an intermediate to nitrobenzene hydrogenation. As a result, a new reaction mechanism was proposed where the hydrogenation of nitrobenzene and nitrosobenzene proceed via separate mechanistic routes, linked by a common adsorbed intermediate; the surface concentration of this adsorbed species controls the hydrogenation pathway followed. Further investigation over Raney nickel suggests this mechanism to be valid over other metals and not specific to palladium. A series of novel bimetallic catalysts were also prepared for use in this study. Characterisation of these catalysts was carried out to determine the nature of the metal-metal interaction on the surface. the evidence suggests mixed metal particles may have been formed on some catalysts. The activity of these catalysts was found to be greatly enhanced following pre-treatment with water vapour in a hydrogen atmosphere. It was postulated that partial oxidation of the metal active sites was occurring and that these systems were more active due to the enhanced adsorption of nitrobenzene. The copper nickel/systems were found to show enhanced catalytic activity, whereas all systems containing cobalt displayed irreversible deactivation following water treatment, which was attributed to the formation of irreducible cobalt aluminium spinel from the CoO formed on the surface.
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Catalysis over molybdenum containing nitride materialsMcKay, David January 2008 (has links)
Reactions involving nitrogen transfer/ fixation are of great industrial interest, as novel processes could help industries meet their increasingly challenging economic and environmental targets. An example of this could be the direct synthesis of aniline from benzene, which would avoid the lengthy, uneconomic, and environmentally unfriendly process currently employed. This work explores the reactivity of bulk and supported transition metal nitride catalysts, with particular emphasis on the possible reactivity of lattice nitrogen within bulk nitride catalysts. The experimental work has focussed on two main objectives: determining the most active transition metal nitride catalyst for ammonia synthesis, and hydrogenating these materials to in the absence of N2 to produce reactive NHx species. These materials were then tested for the possible direct synthesis of aniline from benzene by entrapment of reactive NHX species. The second objective was to achieve nitrogen reactivity with nitride catalysts akin to the Marsvan Krevelen mechanism observed in oxidation catalysis. It has been shown that the binary nitrides, γMo2Nand βMo2N0.78, have comparable ammonia synthesis activities although measurements indicate that βMo2N0.78 may have a much greater activity on a surface area normalised basis. Meanwhile the δMoNphase has an intermediate surface area, but very low activity. The influence of morphology in the ammonia synthesis reaction was investigated by testing nanorod forms of βand γphase molybdenum nitrides and comparing their ammonia synthesis activities with molybdenum nitride powders. Morphology was found to have little effect on the reaction and the influence of structure sensitivity is thought to be limited in this case. What was apparent, was that the highly specific temperature programmed reaction synthesis required to prepare γMo2Nproduced an ammonia synthesis catalyst with no catalytic advantage over one that is prepared in mixtures of H2/N2 (βMo2N0.78). The influence of preparation on the ammonia synthesis activity of ternary nitride catalysts was also investigated by preparing materials in NH3 or H2/N2 atmospheres. Treatment of iron and cobalt molybdenum oxide under H2/N2 was not sufficient to yield a pure phase nitride, however NiMoO4 was fully reduced to Ni2Mo3N. Co3Mo3N, prepared using NH3, was the most active of the ternary nitride catalysts tested, and preparing the materials in H2/N2 failed to increase the activity, with the exception of Ni2Mo3N. Reaction of Co3Mo3N with H2/Ar significantly decreased the nitrogen content of the material, and it is believed that a previously unknown eta12 Co6Mo6N phase has been formed as a result of the nitrogen removal. Hydrogen was shown to be essential to induce this change, despite the fact that most of the eliminated N ended up in the form of N2. Prolonged treatment with H2/Ar at elevated temperature did not remove any additional nitrogen. It is believed that the incomplete loss of nitrogen is a direct consequence of the migration of nitrogen between crystallographic sites as the stoichiometry is reduced. In the case of iron and nickelmolybdenum nitrides the loss of nitrogen was evidenced by combustion analysis, however no new phases of material were formed. Similar experiments, with conducted with different molybdenum nitride polymorphs have shown the removal of nitrogen with a mixed phase of constituent metal and nitrided species, with only βMo2N0.78 fully decomposing to the pure metal. The loss of nitrogen, and hence its potential for reaction, is evident. However, in all cases the predominant form of lost nitrogen is N2, which is believed to be a consequence of the thermodynamics of ammonia decomposition at higher temperatures. Restoration of stoichiometry by treatment with H2/N2 has been observed for a number of materials, i.e. Co3Mo3N, γMo2N. In the case of Co6Mo6N, the NH3 synthesis activity has been found to be comparable with Co3Mo3N. HZSM5 supported nitride catalysts were also tested for ammonia synthesis and it was observed that the introduction of iron as a dopant has significant promotional effects. XPS evidence confirmed the presence of Fe0 in the material, in addition to the molybdenum (oxy)nitride species observed for MoO3/HZSM5. FTIR spectroscopy was used to conduct isotopic nitrogen exchange experiments over nitrided HZSM5 and MoO3/HZSM5. Under the conditions of the experiment, it was shown that the presence of “molybdenum nitride” facilitated the exchange of 15N2 with zeolite framework NHx species. This shows that supported γMo2Nspecies can be a source of reactive and mobile Nspecies, potentially opening up possibilities for its application as a source of spillover nitrogen. A potential route for the direct synthesis of aniline from benzene by hydrogenating ternary nitrides with benzene in the feed, trapping the possible reactive nitrogen species, was investigated. GCMS data showed the no reaction occurred, as only benzene was found in the David Mckay Abstract iv product condensate. In all cases a significant amount of carbon was incorporated/ deposited on the catalysts. In the case of the cobalt molybdenum sample, the XRD data confirmed the conversion of nitride to the carbide, however postreaction XRD of the iron and nickel samples did not indicate carbide formation.
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New approaches for the synthesis of unusual amino acidsFanning, Katherine Nora January 2008 (has links)
The thermal and metal-catalysed aza-Claisen rearrangement of allylic trichlororacetimidates has found widespread application in the synthesis of nitrogen-containing molecules including alkaloids, antibiotics and unnatural amino acids. We have recently investigated the use of this reaction for the rearrangement of chiral molecules. This has led to the development of a highly diastereoselective, ether-directed palladium(II)-catalysed process which has been used for the synthesis of β-hydroxy-α-amino acids. To expand the scope and understanding of the rearrangement, a number of analogues of 1 have been synthesised and subjected to a palladium(II)-catalysed rearrangement. Gizzerosine ((S)-2-amino-9-(4-imidazolyl)-7-azanonanoic acid) is a potent agonist for the H2-receptor. It brings about gizzard erosion and ulceration in broiler chickens. This disease is colloquially known as ‘Black Vomit’ due to bleeding of lesions and subsequent regurgitation. Its biological profile suggests it could be a promising drug candidate for gastric achlorhydria and osteoporosis, although only small amounts can be isolated from fish meal for biological studies. A short and highly efficient synthesis has been developed in ten steps and 31% overall yield. Protein-protein inteactions are the key to organising cellular processes in space and time. Protein-protein interactions are involved in viral fusion and so are promising targets for anti-viral drugs. Photoactivatable amino acids have been used to identify these interactions. Activation by ultraviolet light induces covalent cross-linking (known as photo cross-linking) of the interacting proteins which can be detected with high specificity by simple western blotting. Significant progress has been made towards the development of a stereoselective synthesis of photoactivatable amino acids incorporating a diazirine ring, such as photo-leucine, which generate a reactive carbene after the light induced loss of nitrogen.
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Analysis of the potato sprout inhibitor 1, 4-dimethylnapthalene : HPLC method development and applicationsOteef, Mohammed Dhafer Y. January 2008 (has links)
1,4-Dimethylnaphthalene (1,4-DMN) is a pesticide used for inhibiting the sprouting of stored potatoes, and therefore prolonging the storage time. It is registered for commercial use in different parts of the world (e.g. USA and New Zealand) and its registration process in the EU is at an advanced stage. Limited information is available regarding the behaviour and fate of this pesticide in the environment, and therefore, various studies are required in this field. In such studies, analytical methods for the determination of 1,4-DMN in the different environmental samples are a core element. This work aims to contribute to the knowledge about this pesticide, particularly in the analytical and environmental aspects. Several methods were developed in this work for the determination of 1,4-DMN in environmental samples. HPLC was selected for the final separation and quantification. The development of HPLC separation methods for 1,4-DMN and other related compounds were achieved by the practical step-by-step approach, the use of chromatographic-simulation software, or by a combination of the two approaches. A mixture of seven dimethylnaphthalene isomers and other related naphthalene compounds was used to study the behaviour of these compounds toward the different chromatographic conditions in reversed-phase HPLC with UV detection. This study provides a good understanding of the effect of different chromatographic conditions on the HPLC separation of the compounds studied, and forms a background for the subsequent work in method development. Optimised methods for the separation of this mixture were finally achieved which provide good separation of most of the mixture’s components. In the light of the above study, an HPLC-UV separation method for routine analysis of 1,4-DMN was developed and validated. This method provides good linearity (r2 > 0.999) in the range 0.2 –300 µg/ml, and good precision with %RSD values of 3.45 % and 0.37 % for 0.02 (method LOD) and 50 µg/ml levels. The method was found to be accurate by comparing it statistically to a gas chromatographic method. The two methods were found to produce results which were not significantly different (at the 5% level) by using a regression test. Several extraction procedures were then compared for their efficiency in extracting 1,4-DMN residues in potato samples, and also for their suitability for routine HPLC analysis. A final HPLC method (TMP/Heat method) for the analysis of 1,4-DMN residues in potato samples was then achieved and validated. This method is based on extracting 1,4-DMN from potato peel with a mixture of ethanol and 2,2,4-trimethylpentane (7:3) by heating at 50 oC. A liquid-liquid extraction is achieved (in the same extraction flask) with the water derived from the fresh peel, to end up with 1,4-DMN concentrated in the 2,2,4-trimethylpentane layer. The evaluation of the volume of this layer, in addition to the correction of any loss of 1,4-DMN during the analysis, was achieved by using 2-methylnaphthalene as an internal standard. 2-methylnaphthalene was selected as a suitable internal standard for 1,4-DMN analysis after comparing it with several other compounds (2-ethylnaphthalene, 1-ethylnaphthalene and n-butylbenzene) for the similarity of their behaviour to 1,4-DMN in the extraction and chromatographic separation processes. An aliquot of the 2,2,4-trimethylpentane layer was then analysed directly by HPLC. This method was validated in the range 0.015 to 3 µg/g of potato fresh weight. It was found to have adequate speed, detection sensitivity (LOQ of 0.015 µg/g of potato fresh weight), accuracy (recovery between 90.3 to 106 %) and precision (%RSD between 1.7 to 10.5 %) for routine analysis of 1,4-DMN residues in treated potatoes. For the determination of natural 1,4-DMN in potatoes, a new analytical method was developed for the extraction and quantification of 1,4-DMN at trace levels. The method (ACN/PROP method) uses the advantage of injecting large volumes (100 µl) of the extracts containing 1,4-DMN directly to the HPLC as a means of enhancing the detection sensitivity. This advantage was achieved by using a mixture of acetonitrile : 2-propanol (7:3) as the extraction solution, which is compatible with the mobile phase and miscible with the water derived from potato peel. The resulting extracts were ready for direct analysis with HPLC with no further clean up. In addition, a high ratio of sample : solvent (1:1) was used for further enhancement of the detection sensitivity. This method was validated at 7.5 and 15 µg/kg of potato fresh weight. It was found to be adequate for trace analysis of 1,4-DMN in potatoes with a limit of quantification of 4.5 µg/kg of potato fresh weight, recovery values between 86.4 to 87.1 % and a precision expressed by %RSD between 4.0 to 7.9 %. The ACN/PROP method was used for the determination of the natural levels of 1,4-DMN in potato peel and flesh, in addition to some other plant materials. A small peak was detected in the chromatogram of potato peel extracts, at the right retention time for 1,4-DMN, with an area equivalent to a level of about 4 µg/kg of potato fresh weight. However, it was not possible to confirm the identity of this peak due to its low level and the high background noise. There was no sign of the presence of 1,4-DMN in any of the rest of the plant materials analysed which were potato flesh, apples, orange, celery, spring onion, carrots, rhubarb and poppy seeds. A headspace method and preliminary work using Soxhlet extraction were also examined for the determination of natural 1,4-DMN in potatoes. However, some shortcomings in the development of the methods obstructed the achievement of adequate results. The ACN/PROP method was also optimised for rapid routine analysis of the residues of 1,4-DMN in treated potatoes. The optimised method was validated in the range of 0.03 to 3 µg/g of potato fresh weight, and found to provide good accuracy (recovery between 89.6 to 93.2 %) and precision (%RSD between 1.6 to 7.3 %). In addition, it is a rapid, easy and straightforward procedure. Because of its advantages, this method was used for different applications regarding the distribution and removal of 1,4-DMN residues in treated potatoes. To investigate the distribution and removal of 1,4-DMN residues, potato tubers treated and stored for about 18 weeks under commercial storage conditions were analysed for 1,4-DMN residues. 1,4-DMN residues in individual tubers were in the range of 0.63 to 1.16 µg/g fresh weight after 18 weeks of storage with a low variability factor of about 1.5. The residues were found to be concentrated in the peel layer of the tuber and have relatively even distribution across the different parts of the tuber surface. Washing 1,4-DMN-treated potatoes with water and some other solutions was found to remove insignificant amounts of 1,4-DMN residues from potato tubers. In contrast, heating the peel of 1,4-DMN-treated potatoes in an oven at 75 ± 5 oC removed up to 96 % of 1,4-DMN residues.
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New routes to single molecule magnetsGalloway, Kyle W. January 2009 (has links)
Structural and magnetic studies of citrate coordination clusters are presented for reaction systems involving cobalt(II), copper(II) and nickel(II). The cobalt(II) compounds incorporate cubane structural motifs that are of particular interest for the generation of single molecule magnet (SMM) behaviour. The product family includes a Co4 SMM cluster, a Co6 SMM cluster and a 3D network of linked SMM units. A new route to the erinaceous Co6 cluster crystals is reported, which allows further investigation of the hydration dependent magnetic behaviour of the samples. The structures of a range of copper(II) cluster sizes are described, including a monomer, dimers, trimers and a tetramer. Correlations between structure and magnetic properties are discussed, including the important structural role of the citrate ligand. Two types of citrate-based copper(II) dimers are shown to undergo unusual structural transformations at high pressure. Initial results of the development of 3d-4f systems based on cobalt(II) and copper(II) are described, including a discussion of reaction methodology. Finally, a brief examination of the nickel(II) citrate system includes an overview of the complicated synthetic conditions, then considers the magnetic properties of the nickel(II) analogue of the Co4 cluster.
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Characterisation of macromolecules using electrospray ionization and Fourier transform ion cyclotron resonance mass spectrometryMcDonnell, Liam Andrew January 2001 (has links)
Multipole storage-assisted dissociation (MSAD), in which ions are stored for extended periods of time in a multipole ion-trap, represents one of the most recent and simplest methods by which structurally informative fragments can be obtained. A potential array investigation of MSAD is reported. It was found that the average kinetic energy of the ion was similar to the energy of a single IR photon and the average kinetic energy of an ion during sustained off-resonance irradiation collision-induced dissociation (SORICID), thus explaining the similar fragments that have been obtained using these techniques. The ion's average kinetic energy and its collision frequency was investigated as a function of the ion's charge, mass and mean free path, the space charge present in the hexapole ion trap and the applied radio frequency (RF) potential. All but one of the dependencies, namely the RF potential dependence, were in agreement with experimental results. The disagreement between the experimental results and the simulation results was due to the rate of charge accumulation depending on the applied RF potential. Without prior isolation, MSAD is limited in that it does not permit the isolation of a parent ion and the detection of all fragment ions. Collision-induced dissociation (CID) inside a Fourier transform ion cyclotron resonance (FTICR) cell permits the isolation, fragmentation and detection of all daughter ions. Furthermore the inherent advantages ofFTICR mass spectrometry, higher resolution and mass accuracy, are also afforded to the fragment ions as well as the initial parent ions. Using this technique, all of the components of a commercially available polymeric dye were assigned and the more intense components structurally characterised. This structural characterization highlighted new information regarding the low-energy multiple collision CID of substituted polyesters. Included in these findings was the charge-induced nature of the 1,4-H rearrangement, the participation of amino groups in the fragmentation mechanisms the collisional ring opening of a cyclic polymer. The two previous techniques involve collisions with neutral atoms to increase the internal energy (vibrational) of the ion to obtain the structurally informative fragments. In a similar manner, the fragments obtained after electronic excitation provide a powerful tool with which the electronic structure of molecules can be studied. An ion imaging study of HCI (2+ 1) resonance-enhanced multiphoton ionisation (REMPI) revealed new predissociation channels, an electronic-vibrational-rotational state dependence of the angular distribution of the fragments and vibrational state dependent HCI+ photodissociation. The additional predissociation channels continued the pseudoRydberg continuum of the superexcited states responsible for the previously detected predissociation channels. The complicated angular distribution behavior of the fragments is thought to reflect the diabatic state character of the resonant state, which then determines which superexcited states are accessible.
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Separations by continuous column crystallisationGladwin, R. P. January 1975 (has links)
A continuous column crystalliser has been designed and built using a Schildknecht-type Archimedean transportation screw within a stainless steel jacket. Problems concerned with the surface finish on the inner walls of the jacket which affect crystal transportation have been investigated, leading to effective operation of the apparatus. The process of column crystallisation may be considered as a multistage separation and purification technique; it is applicable to both aqueous and organic systems. In the present work the examination has been undertaken by firstly continuously crystallising a flow of feed solution in the column. Thesecrystals are transported along the screw, melted and some of the melt liquid allowed to flow countercurrently to the crystals thus washing them by reflux. The remainder of the melt liquid is removed as pure product, the impure product provided by the now impure reflux liquid being removed from the opposite extremity of the column. Separations in aqueous solutions which have been investigated include the desalination of brine, concentration of metal salts, the extraction of deuteriai.moxide from a heavy water/water mixture and the concentration of ethanol in water. The purification of organic solvents included the removal of cyclohexane from benzene and the extraction of para-xylene from 0-, m-, p-xylene and ethylbenzene. The unit operations involved in column crystallisation fall into the categories of heat transfer, mass transfer and mixing. In order to examine how dependent the efficient operation of the column is on these factors, the system has been optimised for organic, aqueous and mixed organic/aqueous cases. The variables studied including:- (a) the speed of rotation of the transportation screw (b) the length of the column (c) the attitude of the column (ie crystals transported upwards or downwards). (d) the position of the feed into the column (e) the ratio of the products removal rates (f) the rate of production of crystals Since the scale-up of equipment is an ultimate aim of the present investigation it is necessary to study the results mathematically. Where possible, this examination has been undertaken thus establishing the major factors involved in the separation and purification scheme. It should also be possible to determine whether absolute optimisation of operation is attainable - i.e. does separation increase as the crystal rate increases to infinity or is an optimum separation eventually attained?
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Synthesis, structure and mechanism of polyoxometalate self-assembly : towards designed nanoscale architecturesWilson, Elizabeth Frances January 2009 (has links)
Cryospray (CSI-) and electrospray mass spectrometry (ESI-MS) techniques have been utilised to investigate the key features of the ‘in-solution’, self-assembly processes by which complex polyoxometalate systems, such as ((n-C4H9)4N)2n(Ag2Mo8O26)n and ((n- C4H9)4N)3[MnMo6O18((OCH2)3CNH2)2], are formed. CSI-MS monitoring of the rearrangement of molybdenum Lindqvist anions, [Mo6O19]2-, in the presence of silver(I) ions, into a silver-linked β-octamolybdate structure, has allowed elucidation of the role of small isopolyoxomolybdate fragments and AgI ions in the assembly process. The observation of higher mass fragments, each with increasing organic cation contribution concomitant with their increasing metal nuclearity, has supported the previously proposed hypothesis that the organic cations have a structure-directing role in promoting the mode of POM structure growth in solution. The combined use of UV/vis spectroscopy and real-time CSI-MS monitoring of the reaction solution allowed correlation between the decreasing Lindqvist anion concentration and increasing β-octamolybdate anion concentration. Furthermore, UV/vis spectroscopy was used to show that the rate of decrease in Lindqvist anion concentration, and therefore, the inter-conversion of Lindqvist into β-octamolybdate anions, decreases as the carbon chain length of the alkylammonium cations in the system increases. This approach was extended to use ESI-MS monitoring in examining the formation of the more complex, organic-inorganic, Mn-Anderson polyoxomolybdate structure ((n- C4H9)4N)3[MnMo6O18((OCH2)3CNH2)2]. In this investigation, ESI-MS was used to monitor the real-time, ‘in-solution’ rearrangements of α-octamolybdate anions, [α- Mo8O26]4-, and coordination of manganese(III) cations and tris(hydroxymethyl)aminomethane (TRIS) groups in the formation of the Mn-Anderson- TRIS structure. These investigations have led to the proposal that the rearrangement of [α- Mo8O26]4- anions occurs first through decomposition to [Mo4O13]2- cluster species, i.e. halffragments of the octamolybdate anion; followed by decomposition to smaller, stable isopolyoxomolybdate fragment ions such as dimolybdate and trimolybdate fragment ions. It has then been proposed these fragments subsequently coordinate with the tripodal TRIS ligands, manganese ions, and further molybdate anionic units to form the final, derivatized Mn-Anderson-TRIS cluster. Investigations into the encapsulation of the high oxidation state heteroanion templates {IVIIO6} and {TeVIO6} within polyoxomolybdate clusters, have led to the isolation and characterization of two new, molybdenum Anderson-based POM architectures, i.e. Cs4.67Na0.33[IMo6O24]·ca7H2O and Na4((HOCH2CH2)3NH)2[TeMo6O24]·ca10H2O. The use of coordinating caesium and sodium cations allowed the formation of a closely-packed structure composed of the periodate-centred Anderson clusters arranged into two layers, which then form a repeating ABAB pattern through the lattice. In contrast, the main building-blocks of the tellurium-based cluster system features the [TeMo6O24]6- anions and two coordinated cation arrangements, each composed of a {Na2} dimer and coordinated TEAH+ cation. The presence of this structural motif, and its inter-connection with adjacent clusters, has led to chain-like packing arrangements within the greater lattice structure. The introduction of three aromatic, phenanthridinium-based cations into polyoxometalate systems has led to the isolation and characterization of three new POM architectures with emergent photoactivity. The polyoxometalate framework in each is composed of tungsten Keggin clusters, i.e. [PW12O40]3-, which are introduced into the systems as pre-formed building-blocks. Two of the compounds use derivatives of Dihydro-Imidazo- Phenanthridinium (DIP) molecules as cations, i.e. (DIP-1)[PW12O40]·5DMSO·ca1H2O and (DIP-2)[PW12O40]·5DMSO·ca4H2O, whereas the final compound uses an Imidazo- Phenanthridinium (IP) molecule as the cationic unit, i.e. (IPblue)3[PW12O40]·4DMSO. The use of these cations, which have different steric bulk, geometry and charge states, has led to the formation of interesting packing arrangements within the lattice structures of all three compounds. Additionally, further characterization of these compounds has revealed they all possess emergent photoactivity, in the form of intermolecular charge transfer bands in the solid state. Some degree of intermolecular charge transfer in the solution state has also been detected for the DIP-2-based structure.
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