Chemistry Commons^™

Preparation And Rapid Analysis Of Antibacterial Silver, Copper And Zinc Doped Sol–Gel Surfaces, Brendan Duffy, Swarna Jaiswal, Patrick Mchale

Articles

The colonisation of clinical and industrial surfaces with microorganisms, including antibiotic-resistant strains, has promoted increased research into the development of effective antibacterial and antifouling coatings. This study describes the preparation of metal nitrate (Ag, Cu, Zn) doped methyltriethoxysilane (MTEOS) coatings and the rapid assessment of their antibacterial activity using polyproylene microtitre plates. Microtitre plate wells were coated with different volumes of liquid sol–gel and cured under various conditions. Curing parameters were analysed by thermogravimetric analysis (TGA) and visual examination. The optimum curing conditions were determined to be 50–70C using a volume of 200ul. The coated wells were challenged with Gram-positive …

Existence Of A Minimizer For The Quasi-Relativistic Kohn-Sham Model, Carlos Argáez García, Michael Melgaard

Articles

We study the standard and extended Kohn-Sham models for quasi-relativistic N-electron Coulomb systems; that is, systems where the kinetic energy of the electrons is given by the quasi-relativistic operator (see article) . For spin-unpolarized systems in the local density approximation, we prove existence of a ground state (or minimizer) provided that the total charge Z of K nuclei is greater than N-1 and that Z is smaller than a critical charge (see article).

Characterization And Electrochromic Properties Of Poly(2,3,5,6-Tetrafluoroaniline): Progress Towards A Transparent Conducting Polymer, Lavinia Astratine, Edmond Magner, John Cassidy, Tony Betts

Articles

Electrochromic films of poly(2,3,5,6-tetrafluoroaniline) (PTFA) were formed on ITO substrates from aqueous solutions utilising perchloric acid (HClO₄) as dopant. Electrochemical and spectroscopic characterization of PTFA films was performed in background electrolyte and in solutions with the addition of tetrahydrofuran. When the PTFA film was removed from its growth medium, a significant decrease in the faradaic current was observed. The faradaic response increased on addition of tetrahydrofuran which facilitates ion movement through the polymer matrix. PTFA films deposited on ITO substrate were orange and light orange in the oxidized and reduced forms, respectively. The films were ca. 25 nm …

Structure-Reactivity Studies Of Simple 4-Hydroxyprolinamide Organocatalysts In The Asymmetric Michael Addition Reaction Of Aldehydes To Nitroolefins, Fintan Kelleher, John Watts, Lien Luu, Vickie Mckee, Ed Carey

Articles

A series of simple 4-hydroxyprolinamides was synthesised and they were found to act as organocatalysts for the asymmetric conjugate addition of aldehydes to nitroolefins in excellent yields (98%), with complete diastereoselectivity (99:1, syn:anti) and enantioselectivity (98% e.e. for syn). Furthermore, the use of low catalyst loadings (5 mol%) and a low aldehyde molar excess (1.5 equivalents) were achieved.

The Driving Forces Of Change In Energy-Related Co2 Emissions In Ireland: A Multi-Sectoral Decomposition From 1990 To 2007, Tadhg O'Mahony, Peng Zhou, John Sweeney

Articles

Ireland recorded significant growth in energy-related carbon emissions from 1990 to 2007 as the country underwent rapid economic development. Using the LMDI decomposition analysis method, this paper aims to identify and analyse the driving forces of CO2 emissions in eleven final energy consuming sectors. This multi-sectoral analysis is based on four economic sectors, the residential sector and gives a detailed representation of transport in keeping with UNFCCC recommendations. Scale, structure and intensity effects are explored and substantial heterogeneity in sectoral performance is observed. Scale growth in economic and transport activity was considerable. Some improvements in energy intensity were recorded in …

Functionalized Ruthenatricarbadecaborane Via Selective Cage Iodination And Sonogashira Coupling Reactions, Ariane Perez-Gavilan, Larry Sneddon, Patrick J. Carroll

Articles

Selective iodination of the cyclopentadienylruthenium tricarbadecaboranyl complexes 1-(η5-C5H5)–2-Ph–closo-1,2,3,4-RuC3B7H9 (1) and 1-(η5-C5(CH3)5)–2-Ph–closo-1,2,3,4-RuC3B7H8 (2) to form their mono-iodo derivatives, 1-(η5-C5H5)–2-Ph–6-I–closo-1,2,3,4-RuC3B7H9 (3) and 1-(η5-C5(CH3)5)–2-Ph–6-I–closo-1,2,3,4-RuC3B7H8(4), was achieved in 90% yields by their reactions with ICl in CH2Cl2 solutions. Also isolated in trace amounts from the reaction with 2 was the di-iodo 1-(η5-C5(CH3)5)–2-Ph–6,11-I2–closo-1,2,3,4-RuC3B7H7, (5) complex. The sonication-promoted Sonogashira coupling reaction of 3 with terminal acetylenes catalyzed by Pd(dppf)Cl2/CuI yielded the functionalized ruthenatricarbadecaboranyl complexes 1-(η5-C5H5)–2-Ph–6-(Ph-C≡C)–closo-1,2,3,4-RuC3B7H8 (6), 1-(η5-C5H5)–2-Ph–6-[CH3CH2C(O)OCH2-C≡C]–closo-1,2,3,4-RuC3B7H8 (7), …

Preparation And Characterization Of A Composite Of Gold Nanoparticles And Single-Walled Carbon Nanotubes And Its Potential For Heterogeneous Catalysis, Anne Shanahan, James Sullivan, Mary Mcnamara, Hugh Byrne

Articles

A single-walled carbon nanotube-supported gold nanoparticle composite was prepared and characterized by X-ray diffraction, scanning transmission electron microscopy/scanning electron microscopy/transmission electron microscopy, energy-dispersive X-ray analysis, atomic absorption spectroscopy, nitrogen adsorption, Raman spectroscopy, and ultraviolet-visible spectroscopy. The Au particles were found to be crystalline, with a well-defined and narrow particle-size distribution, centered around 7 nm. The activity and selectivity of the composite for solventless aerobic oxidation of a secondary alcohol were examined, and a conversion efficiency of 95% was obtained.

Human Heuristics: Understanding The Impacts For Pharmaceutical Quality Risk Management, Nuala Calnan (Editor)

Conference Papers

This paper addresses the influence of human heuristics (Biases) on the assessment of risk. A core principle underpinning effective Risk Management is the principle that Risk Management explicitly addresses uncertainty i.e., that it explicitly takes account of uncertainty, the nature of that uncertainty, and how it can be addressed. Heuristics are cognitive behaviours which come into play when we make judgements in the presence of uncertainty. How these behaviours are manifested is still the subject of much research, but there is evidence in the literature that heuristics are a source of significant bias and errors in judgement. Awareness of the …

The Preparation And Characterisation Of Silver Nanomaterials And Their Application In Sensing Techniques, Aoife Power

Doctoral

In this work the impact of nanomaterial, specifically silver nanostructures, on sensing techniques is investigated. The work can be divided in to three sections, preparation and characterisation of silver nanoparticles, their application as a nanocomposite based chemiresistor humidity sensing device and finally their application within the surface enhanced (resonance) Raman spectroscopy, SE(R)RS, technique. In the first study silver nanoparticles were prepared as aqueous colloidal dispersions. The colloids were of either a defined diameter (average diameter ~ 20 nm) with high silver loading or lower loaded colloids of tuneable morphology and hence optical properties. In a subsequent study the high load …

Benchmarking The Pharmaceutical Industry: A Briefing On An Irish Research Study, Nuala Calnan (Editor)

Conference Papers

This paper presents an Irish research study currently being undertaken by the Pharmaceutical Regulatory Science Team at the Dublin Institute of Technology (DIT) into the impact of new pharmaceutical regulatory guidance on the development and manufacture of medicinal drug products.

It launches a Pharmaceutical Industry Benchmarking Questionnaire designed to assess the impact and level of implementation of the ICH Tripartite Quality Guidance Q8, Q9 and Q10.

Synthesis And Characterisation Of Macrocycles Containing Both Tetrazole And Pyridine Functionalities, Adrienne Fleming, Jackie Gaire, Fintan Kelleher, John Mcginley, Vickie Mckee

Articles

The syntheses of tetra-tetrazole macrocycles containing at least one 2,6-bis(tetrazole)pyridine unit, linked by a variety of n-alkyl (n = 3, 5, 7 or 9 carbon atoms) chain lengths, are described. There has been no previous incorporation of the pyridine moiety into a tetra-tetrazolophane macrocycle. The crystal structure of one such tetra-tetrazole macrocycle has also been structurally characterised and revealed a bowl-shaped conformation.

Synthesis, Co-Polymerisation And Electrochemical Evaluation Of Novel Ferrocene-Pyrrole Derivatives, Mary Deasy, Eithne Dempsey, Geok Hong Soon, Oliver Worsfold

Articles

New ferrocene derivatives, ((4-(1H-pyrrol-1-yl)phenoxy)carbonyl) ferrocene (4) and (6-(4-(1H-pyrrol-1-yl)phenoxy)hexyl) ferrocene (7) were synthesised, characterised and electrochemically evaluated as redox active films formed via anodic oxidation with pyrrole. Thin film studies were conducted and films formed from both compounds resulted in a stable Fe ^II/III redox couple with E^o = 0.04V and 0.36V vs. Ag/Ag⁺ for (7) and (4) respectively. Both potential sweeping and chronocoulometry were employed for film formation with the former resulting in controllable, reproducible film deposition. Growth conditions and solution concentrations were varied in the case of both compounds in order to assess …

Application Of Niobium Enriched Ormosils As Thermally Stable Coatings For Aerospace Aluminium Coatings, P.C. Rajath Varma, Mohamed Oubaha, Pradeepan Periyat, Colette Mcdonagh, Brendan Duffy

Articles

The aim of this experimental research is to study the ability of niobium rich sol-gel coatings to withstand thermal stress, while remaining impermeable to corrosive agents for the protection of aerospace alloys. The coating material is developed via polymeric sol-gel synthesis employing 3-(trimethoxysilyl)propylmethacrylate (MAPTMS) and niobium ethoxide precursors as a source of silicon and niobium, respectively. The beneficial effect of niobium inclusion within coating was characterised spectroscopically, calorimetrically and electrochemically. The thermal cycling effects of the coating were studied using microscopic and accelerated test methods. Electrochemical tests showed that corrosion current of the material was 2 orders lower in magnitude …

Crystallisation And Phase Transition Characteristics Of Sol-Gel-Synthesized Zinc Titanates, Suresh Pillai, Michael Seery, Nicholas Nolan

Articles

No abstract provided.

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.

Enhancing The Learning Experience: Learning For The Unknown Future, Barry Ryan

Conference papers

In this presentation the effects of an altered teaching methodology, in which the "student as producer" approach was adopted, are outlined. Currently, many students exist as knowledge consumers; however, Neary and Winn (2009) have suggested the positive effect on students learning through the inclusion of research-like activities at the core of the undergraduate curriculum; the students act as "producers" of knowledge.

Integrating Formative Feedback Into Individual And Group Assessments In A First Year Organic Chemistry Module, Barry Ryan, Julie Dunne

Conference papers

It is common for science undergraduates, particularly first year students, to remark that they do not receive appropriate support in their transition from second level to third level education; particularly in effective scientific laboratory report writing, new subject area preparedness and technical ‘know-how’ [1]. This is compounded by the insufficient, or inappropriate, feedback offered to students in these problem areas. The pedagogical emphasis often focuses on quantity rather than quality; both in report writing and content delivered. This publication describes an assessment methodology redesign to, firstly, incorporate on-line formative feedback and; secondly, to introduce one-to-one and one-to-group lab report feedback …

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 …

Sol-Gel Synthesis And Characterisation Of Novel Metal Oxide Nanomaterials For Photocatalytic Applications, Nicholas T. Nolan

Doctoral

This thesis presents a study of the effect of chemical modifiers and dopants on both the anatase to rutile transformation and also the photocatalytic efficiency of semiconductor nanomaterials. The main focus of the work is based on the crystallisation and phase transformation of the widely investigated semiconductor metal oxide, titanium dioxide (TiO2) Of the three polymorphs associated with titanium dioxide, anatase is widely regarded as the most effective photocatalyst. Typically anatase will transform to rutile in the temperature range 600 – 700 °C however, modification of a titanium precursor with a chelating agent can result in extended transformation temperature. The …

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 …