Chemistry Commons^™

Now For The Science Bit: Implementing Community-Based Learning In Chemistry, Claire M. Mcdonnell, Patricia Ennis, Leslie Shoemaker

Articles

Purpose – The purpose of this paper is to contribute to the understanding of student learning from community engagement by critically assessing the implementation of this pedagogical approach in the context of teaching and learning chemistry and also evaluating the role of personal development in student-community engagement.

Design/methodology/approach – A case study on the implementation since 2007 of community-based learning (also called service-learning) projects in an academic department in Ireland is presented. Analysis of assessment grades, student reflective accounts and evaluation questionnaires informs this work as does a recently completed self-assessment of our activities using Shumer’s Self-Assessment for Service Learning. …

Di-Tert Butyl Chlorosilane, Gráinne Hargaden, Timothy O'Sullivan

Articles

No abstract provided.

Water-Soluble Cuii And Mnii Bis-Phenanthroline Octanedioate Complexes With Unprecedented Nano And Picomolar In Vitro Cytotoxicity As Promising Leads For Chemotherapeutic Drug Development, Andrew Kellett, Mark O'Connor, Malachy Mccann, Orla L. Howe, Alan Casey, Pauric Mccarron, Kevin Kavanagh, Mary Mcnamara, Sean Kennedy, Donald D. May, Philip S. Skell, Denis O'Shea, Michael Devereux

Articles

Dinuclear Cu^II and Mn^II bis-phenanthroline octanedioate complexes exhibit rapid, unprecedented nano and picomolar in vitro cytotoxicity against colorectal cancer lines and are less toxic than cisplatin when examined in vivo. The complexes are potent generators of cellular reactive oxygen species, avid DNA binders and induce O₂ dependent cleavage of DNA. The Cu(II) complex was found to have self-cleaving nuclease activity.

Non Aggregated Colloidal Silver Nanoparticles For Surface Enhanced Resonance Raman Spectroscopy, Aoife Power, John Cassidy, Tony Betts

Articles

Silver nanoparticles with a tuneable l max were produced as colloids by heterogeneous nucleation. The synthesis process is both fast and repeatable, producing stable PVA capped nanoparticles. The colloid’s effectiveness in the SERRS system was investigated using Rhodamine 6G, R6G, Crystal Violet, CV, and Malachite Green, MG, as probe molecules. A clear sensing trend was observed, where the Raman signal emitted was significantly enhanced by the addition of silver nanoparticles. A build up of signal intensity is observed until an optimum ratio is achieved, followed by a decline in signal intensity as the concentration of nanoparticles is further increased. The …

Chromium Salen, Gráinne Hargaden, Pier Giorgio Cozzi

Articles

No abstract provided.

A Practical Photoelectrochemical Cell Using Nonprecious Metal Electrodes, Patrick Enright, Tony Betts, John Cassidy

Articles

Abstract: Photoelectrochemical cells (PECs) can be used to harvest light from the oxidation of dissolved organic matter. Similar to fuel cells but requiring light to operate, PECs contain a light assisted electrode that oxidises electron rich materials (anode); these electrons then flow to a typically Pt cathode where O₂ is normally the electron acceptor. In this work a PEC cell containing inexpensive materials was shown to (a) mineralise typical organic compounds present in waste water and (b) produce electricity from their decomposition. The PEC cell consisted of a TiO₂ coated conducting ink anode exposed to a light source, …

Comment On C.E. Close, M.R. Gleeson And J.T. Sheridan "Monomer Diffusion Rates In Photopolymer Material Part 1. Low Spatial Frequency Holographic Gratings, Vincent Toal, Suzanne Martin, Izabela Naydenova

Articles

COMMENT: on C. E. Close, M. R. Gleeson and J. T. Sheridan “Monomer diffusion rates in photopolymer material.Part I. Low spatial frequency holographic gratings” J. Opt. Soc. Am. B / Vol. 28, No. 4 / April 2011 pp 658- 666 [1]

Water-Soluble Bis(1,10-Phenanthroline) Octanedioate Cu2+ And Mn2+ Complexes With Unprecedented Nano And Picomolar In Vitro Cytotoxicity: Promising Leads For Chemotherapeutic Drug Development, Andrew Kellett, Mark O'Connor, Malachy Mccann, Orla Howe, Alan Casey, Pauraic Mccarron, Kevin Kavanagh, Mary Mcnamara, Sean Kennedy, Donald May, Philip Skell, Denis O'Shea, Michael Devereux

Articles

Dinuclear Cu^II and Mn^II bis-phenanthroline octanedioate complexes exhibit rapid, unprecedented nano and picomolar in vitro cytotoxicity against colorectal cancer lines and are less toxic than cisplatin when examined in vivo. The complexes are potent generators of cellular reactive oxygen species, avid DNA binders and induce O₂ dependent cleavage of DNA. The Cu(II) complex was found to have self-cleaving nuclease activity.

Development And Validation Of A Rapid Multi-Class Method For The Confirmation Of Fourteen Prohibited Medicinal Additives In Pig And Poultry Compound Feed By Liquid Chromatography Tandem Mass Spectrometry, Mark Cronly, Patrice Behan, Barry Foley, Liam Regan, Marella Gallagher, Sean Earley, Paula Shearan, Edward Malone

Articles

A confirmatory method has been developed to allow for the analysis of fourteen prohibited medicinal additives in pig and poultry compound feed. These compounds are prohibited for use as feed additives although some are still authorised for use in medicated feed. Feed samples are extracted by acetonitrile with addition of sodium sulphate. The extracts undergo a hexane wash to aid with sample purification. The extracts are then evaporated to dryness and reconstituted in initial mobile phase. The samples undergo an ultracentrifugation step prior to injection onto the LC-MS/MS system and are analysed in a run time of 26 minutes. The …

Determination Of Threshold Exposure And Intensity For Recording Holograms In Thick Green-Sensitive Acrylamide-Based Photopolymer, Mohammad Sultan Mahmud, Izabela Naydenova, Tzwetanka Bebeva, Raghavendra Jallapuram, Suzanne Martin, Vincent Toal

Articles

For optical data storage applications, it is essential to determine the lowest intensity (also known as threshold intensity) below or at which no data page or grating can be recorded in the photosensitive material, as this in turn determines the data capacity of the material. Here, experiments were carried out to determine the threshold intensity below which the formation of a simple hologram—a holographic diffraction grating in a green-sensitized acrylamide-based photopolymer—is not possible. Two main parameters of the recording layers—dye concentration and thickness—were varied to study the influence of the density of the generated free radicals on the holographic properties …

Rapid Multi-Class Multi-Residue Method For The Confirmation Of Chloramphenicol And Eleven Nitroimidazoles In Milk And Honey By Liquid Chromatography Tandem Mass Spectrometry, Mark Cronly, Patrice Behan, Barry Foley, Liam Regan, Sheila Martin, Michael Doyle, Edward Malone

Articles

A confirmatory method has been developed to allow for the analysis of eleven nitroimidazoles and also chloramphenicol in milk and honey samples. These compounds are classified as A6 compounds in annex IV of council regulation 2377/90 and therefore prohibited for the use in animal husbandry. Milk samples are extracted by acetonitrile with addition of NaCl, while honey samples are first dissolved in water before a similar extraction. Honey extracts undergo a hexane wash to remove impurities. Both milk and honey extracts are evaporated to dryness and reconstituted in initial mobile phase. These are then injected onto an LC-MS/MS system and …

A Systematic Study Of The Effect Of Silver On The Chelation Of Formic Acid To A Titanium Precursor And The Resulting Effect On The Anatase To Rutile Transformation Of Tio2, Nicholas Nolan, Michael Seery, Steve Hinder, Linda Healy, Suresh Pillai

Articles

Anatase to rutile transition in an unmodified synthetic titania usually occurs at a temperature range of 600 – 700 °C. Various methods such as addition of metallic and non-metallic dopants and modifying the precursor have previously been reported to influence the anatase to rutile transition temperature. In the current study, the effect of addition of increasing amounts of silver to the extent of chelation of a formate group to a titanium precursor and the resulting effects on the transformation of anatase to rutile has been studied. The addition of silver (0, 1, 3 and 5 mol %) on the anatase …

Highly Visible Light Active Tio2-Xnx Heterojunction Photocatalysts, Vinodkumar Etacheri, Michael Seery, Steven Hinder, Suresh Pillai

Articles

Nitrogen doped anatase-rutile heterojunctions are successfully synthesized through an ethylene-diaminetetraacetic acid (EDTA) modified sol-gel process.An FT-IR study of EDTA modified TiO2 gel confirms the existence of an ionic intermediate (as indicated by a Δν value of 233 cm-1).Differential scanning calorimetry (DSC), X-ray diffraction (XRD), and Raman spectroscopy are employed to study the phase evolution, phase purity, and crystallite size of samples. Formations of O-Ti-N and N-Ti-N bonds in calcined samples are confirmed using XPS and FT-IR spectro- scopy. AllEDTAmodified samples show significantly higher visible light photocatalytic activity than the unmodified sample. The most active nitrogen doped heterojunction obtained at 400C …

Dual-Action Hygienic Coatings: Benefits Of Hydrophobicity And Silver Ion Release And Surface Analysis, Niall Stobie, Brendan Duffy, John Colreavy, Patrick Mchale, Steven Hinder, Declan Mccormack

Articles

Coatings that demonstrate reduced attachment of crystalline precipitates and the medical device colonising Staphylococcus epidermidis were prepared by the immobilisation of silver doped perfluoropolyether–urethane siloxane thin films on glass substrates. The presence of stratified hydrophobic perfluoropolyether groups protects the coating surface from the attachment of crystalline hydrophilic species such as chlorides and phosphates, whilst silver ion release inhibited attachment of S. epidermidis and subsequent biofilm formation in vitro. The release of silver ions protects the perfluoro groups from the hydrophobic interactions of S. epidermidis cells, which can reduce the hydrophobicity of the protective coating. These coatings also exhibited significant antibacterial …

Structure-Reactivity Relationships Of L-Proline Derived Spirolactams And A-Methyl Prolinamide Organocatalysts In The Asymmetric Michael Addition Reaction Of Aldehydes To Nitroolefins., Fintan Kelleher, Sinead Kelly, John Watts, Vickie Mckee

Articles

L-Proline derived spirolactams and a-methyl prolinamides act as organocatalysts for the asymmetric conjugate addition of aldehydes to nitroolefins in excellent yields, with good diastereoselectivity and enantioselectivity. Furthermore, low catalyst loadings (5 mol%) and a low aldehyde molar excess (1.5 molar equivalents) were achieved.

Single Step Morphology-Controlled Synthesis Of Silver Nanoparticles, Vinodkumar Etacheri, Reenamole Georgekutty, Michael Seery, Suresh Pillai

Articles

Silver nanoparticles having different size and plasmon resonances were synthesized through a single step aqueous based method. The current procedure was based on the reduction of silver ions by ascorbic acid in the presence of sodiumborohydride and trisodium citrate. Triangular colloidal nanoparticles having different plasmon resonances (and hence different size and colours) were synthesized by varying only the concentration of ascorbic acid. These nanoparticles were found to be stable without using any surfactants or polymers. This study revealed a strong correlation between particle growth and concentration of constituent chemicals. Crystallinity and phase purity of the silver samples were investigated through …

Interaction Between Langmuir And Langmuir- Blodgett Films Of 5,11,17,23-Tetra-Tert-Butyl-25,27-Diethoxycarbonyl Methyleneoxy-26,28,Dihydroxycalix[4]Arene And 5,17-(9h-Fluoren-2-Yl)Methyleneamino)-11,23-Di-Tert-Butyl-25,27-Diethoxycarbonyl Methyleneoxy-26,28-Dihydroxycalix[4]Arene With Aqueous Copper And Lithium Ions., Mary Deasy, Fintan Kelleher, Faridah L. Supian, Tim H. Richardson, James P. Ward, Vickie Mckee

Articles

The binding interactions between aqueous copper (Cu2þ ) and lithium (Li þ ) ions and Langmuir monolayers and Langmuir-Blodgett (LB) multilayers have been investigated by studying surface pressure-area (Π-A) isotherms and surface potential-area (ΔV-A) behavior in order to find the effective dipole moment, μ^, of the calixarene molecules in the uncomplexed and complexed states. The orientation of both calix[4]arenes, namely, 5,11,17,23-tetra-tert-butyl- 25,27-diethoxycarbonyl methyleneoxy-26,28-dihydroxycalix[4]arene and 5,17-(9H-fluoren-2-yl)methyleneamino)- 11,23-di-tert-butyl-25,27-diethoxycarbonyl methyleneoxy-26,28-dihydroxycalix[4]arene, is such that the plane of the calix ring is parallel with the plane of the water surface regardless of the ion content of the subphase. The Gibbs equation was used to interpret …

Corrosion Protection Properties Of Various Ligand Modified Organic Inorganic Hybrid Coating On Aa 2024-T3, Rajath Varma, John Cassidy, Mohamed Oubaha, Colette Mcdonagh, John Colreavy, Brendan Duffy

Articles

The inclusion of zirconium precursors to prepare organosilane solgel coatings improves the corrosion protection performance of the coatings on aluminium and steel. The inherent differences in the hydrolysis rates of the silane and zirconium precursors, various ligands were used to control the hydrolysis by decreasing the number of reactive alkoxide group. Hybrid sols were synthesised using 3-(trimethoxysilyl) propylmethacrylate (MAPTMS) and zirconium n-propoxide chelated with organic ligands including different organic acids, acetyl acetone and 2 2’ bipyridyl. The effects of zirconia inclusion on the properties of the coatings were compared on the aerospace alloy AA 2024-T3. Electrochemical analysis and salt spray …

Corrosion Protection Of Aa 2024-T3 Aluminium Alloys Using 3, 4-Diaminobenzoic Acid Chelated Zirconium-Silane Hybrid Sol-Gels, P.C. Rajath Varma, John Colreavy, John Cassidy, Mohamed Oubaha, Colette Mcdonagh, Brendan Duffy

Articles

Organic-inorganic polymers formed by hydrolysis/condensation reactions of alkoxide precursors, such as organically modified silanes (Ormosils) have found applications as electronic, optical and protective coatings. Such coatings possess important characteristics such as chemical stability, physical strength and scratch resistance. Further performance improvement is achieved through the incorporation of zirconium and titanium based nanoparticles, also formed through the sol-gel process. However due to the inherent difference in the reactivity of the precursors, the hydrolysis of each precursor must be carried out separately before being combined for final condensation. Zirconium precursors are commonly chelated using acetic acid or acetyl acetonate prior to hydrolysis, …

Silver Nanoparticle Polymer Composite Based Humidity Sensor, Aoife Power, Tony Betts, John Cassidy

Articles

Silver nanoparticles were synthesised by a chemical reduction process in order to produce an aqueous colloidal dispersion. The resulting colloids were then characterised by a combination of UV-Vis spectroscopy, dynamic light scattering, X-ray diffraction and transmission electron microscopy and the nanoparticles were found to have an average diameter of 20–22 nm. The Ag/polymer nanocomposites were then applied to platinum interdigital electrodes as sensor coatings and the capability of the resulting sensor as a humidity detector investigated. With the application of 1 V, a current developed which was found to be directly proportional to humidity levels. The sensor gives a reversible, …

Rapid Microwave Synthesis Of Mesoporous Tio2 For Electrochromic Displays, Suresh Pillai, Declan Mccormack, Pradeepan Periyat, Nigel Leyland, David Corr, John Colreavy

Articles

No abstract provided.

The Antioxidant Properties Of Whey Permeate Treated Fresh-Cut Tomatoes, Lubna Ahmed, Ana Belen Martin-Diana, Daniel Rico, Catherine Barry-Ryan

Articles

The aim of this research was to analyse the effects of three types of cheese whey permeate treatment on the antioxidant properties of fresh-cut tomatoes. Tomatoes were treated with whey permeate concentrate (PC), delactosed permeate (DP) and delactosed concentrate (DC), stored at 4 C for 10 days and compared to samples treated with the industry standard, chlorine (120 ppm). Samples treated with DP retained significantly higher antioxidant activity (FRAP) and total phenols (TP), when compared with those treated with PC and DC. DP showed significantly higher results than chlorine for DPPH, FRAP and TP. In DPPH assay, all whey permeate-treated …

Spectroscopic Investigation Of The Anatase-To-Rutile Transformation Of Sol-Gel Synthesised Tio2 Photocatalysts, Nicholas Nolan, Suresh Pillai, Michael Seery

Articles

Among the three major phases in titania, anatase is reported to be a better photocatalytically active phase. Anatase to rutile transformations, under normal conditions, usually occurs at a temperatue range of 600- 700 °C. Various chemical additives have previously been employed to extend the anatase transition to higher temperatures. Effect of employing various concentrations of formic acid and water on phase transition has systematically been studied by XRD, FTIR and Raman spectroscopy. A considerably higher anatase phase (41%) has been obtained at 800 ºC and 10% anatase composition is retained after annealing the materials at 900 ºC for the optimised …

One-Pot Synthesis Of Anionic (Nitrogen) And Cationic (Sulfur) Codoped High-Temperature Stable, Visible Light Active, Anatase Photocatalysts, Suresh Pillai, Declan Mccormack, Steven Hinder, Pradeepan Periyat

Articles

No abstract provided.

Influence Of Magnesium Nitrate On The Corrosion Performance Of Sol-Gel Coated Aa2024-T3 Aluminium Alloy, Rajath Varma, Brendan Duffy, John Cassidy

Articles

Traditional anti-corrosion technology has relied heavily on using reducible metal species, predominantly hexavalent chromium (Cr(VI)), for protecting reactive metal alloys such as aluminium which is extensively used in the aerospace sector. However, the impending changes in the use of Cr(VI) in Europe and the United States have forced aerospace manufacturers to examine alternative materials for protecting aluminium. One of the most promising alternatives being investigated are organosilane based sol-gels containing anticorrosion additives. In this work the anti-corrosion properties of magnesium (II) nitrate (Mg(NO3)2) as a inhibitor was investigated at different concentrations (0.1% - 1.0 wt %) in a methyltriethoxysilane (MTEOS) …

Silver Doped Perfluoropolyether-Urethane Coatings: Antibacterial Activity And Surface Analysis, Niall Stobie, Brendan Duffy, Steven Hinder, Patrick Mchale, Declan Mccormack

Articles

The colonisation of clinical and industrial surfaces with pathogenic microorganisms has prompted increased research into the development of effective antibacterial and antifouling coatings. There is evidence that implanted biomedical surfaces coated with metallic silver can be inactivated by hysiological fluids, thus reducing the bioactivity of the coating. In this work, we report the biofilm inhibition of Staphylococcus epidermidis using a roomtemperatureprocessedsilver dopedperfluoropolyether-urethane coating. The release of silver ions from these fluoropolymers over a six-day period inhibited bacterial encrustation – as observed by scanning electron microscopy (SEM). X-ray photoelectron spectroscopy (XPS) analysis indicated differences in carbon, fluorine and sodium surface composition …

Effect Of Organic Chelates On The Performance Of Hybrid Sol–Gel Coated Aa2024-T3 Aluminium Alloys, Rajath Varma, John Colreavy, John Cassidy, Mohamed Oubaha, Colette Mcdonagh, Brendan Duffy

Articles

Sol–gels are organic–inorganic polymers formed by hydrolysis/condensation reactions of alkoxide precursors, primarily silanes, which have found applications as electronic, optical and protective coatings. These coatings possess important characteristics such as chemical stability, physical strength and scratch resistance. Further performance improvement is achieved through the incorporation of zirconium and titanium based nanoparticles, also formed through the sol–gel process. However due to the inherent difference in the reactivity of the precursors, the hydrolysis of each precursor must be carried out separately before being combined for final condensation. Zirconium precursors are commonly chelated using acetic acids, prior to hydrolysis, to lower the hydrolysis …

One-Pot Synthesis Of Anionic (Nitrogen) And Cationic (Sulfur) Codoped High-Temperature Stable, Visible Light Active, Anatase Photocatalysts, Suresh Pillai, Declan Mccormack, Steven Hinder, Pradeepan Periyat

Articles

No abstract provided.

Working Report On The Status Quo Of Nanomaterials Impact On Health And Environment, Harald Krug, Margarita Apostolova, Marite Arija Bake, Gordon Chambers, Horia Chiriac, Eva Herzog, Victoria Hand, Jürgen Höck, Peter Hoet, Nicoleta Lupu, Declan Mccormack, Maja Remskar, George Robillard, Jamila Smisterova, Jan Stetkiewicz, Speranta Tanasescu, Aris Tsatsakis, David Vaughn, Peter Wick, Jörg Wörle-Knirsch

Articles

Nanotechnology is regarded as one of the key technologies of the future and associated with high expectations by politics, science and economy. Artificially produced nanosized particles and nanoscale system components have new properties which are of importance for the development of new products and applications. Such new properties of materials and substances result from the special properties of surfaces and interfaces and in part, from the geometric shape of the material. In theory nanoparticles (NPs) can be produced from nearly any chemical; however, most NPs that are currently in use today have been made from transition metals, silicon, carbon (single-walled …

Real-Time Plasma Controlled Chemistry In A Two-Frequency, Confined Plasma Etcher, Vladimir Milosavljevic, Albert R. Ellingboe, Cezar Gaman, John V. Ringwood

Articles

The physics issues of developing model-based control of plasma etching are presented. A novel methodology for incorporating real-time model-based control of plasma processing systems is developed. The methodology is developed for control of two dependent variables (ion flux and chemical densities) by two independent controls (27 MHz power and O2flow). A phenomenological physics model of the nonlinear coupling between the independent controls and the dependent variables of the plasma is presented. By using a design of experiment, the functional dependencies of the response surface are determined. In conjunction with the physical model, the dependencies are used to deconvolve the sensor …