COST : action chemistry conference on supramolecular chemistry in water

Scientists and chemists from 18 countries gathered in Malta for the 3rd Scientific Meeting on Supramolecular Chemistry in Water between the 9 − 11th of November 2013 at the Old University Building on St Paul Street in Vallettapeer-reviewe

2015 researcher's mini-symposium

Postgraduate researchers from the Faculties of Science, Engineering, Medicine & Surgery and Health Sciences gathered for a forum to present their research interests. The symposium was held in the afternoon of 30 January 2015 in the Engineering Lecture Theatre. The symposium promoted multi-disciplinary networking between various university faculties. Participants were invited based on research topic diversity and gender balance.peer-reviewe

Medical diagnostics using designed molecules with sense and logic

Luminescent molecules responsive to cations, anions and even small molecules can be designed with the appropriate selectivity and sensitivity for monitoring physiological and pathological levels of analytes. We highlight some recent examples of designed molecules that can sense for a specific analyte or a combination of analytes in blood and in living cells. Furthermore, we demonstrate how molecules can be designed with built-in algorithms according to principles of Boolean logic to perform information processing. The potential future application of molecular systems able to perform multi-analyte sensing as `lab-on-a-molecule' systems for medical and environmental diagnostics is also presented.peer-reviewe

Self-assembly of multi-component fluorescent molecular logic gates in micelles

A recent strategy for developing supramolecular logic gates in water is based on combinations of molecules via self-assembly with surfactants, which eliminates the need for time-consuming synthesis. The self-assembly of surfactants and lumophores and receptors can result in interesting properties providing cooperative e ffects useful for molecular information processing and other potential applications such as drug delivery systems. This article highlights some of the recent advancements in supramolecular information processing using microheterogeneous media including micelles in aqueous solution.peer-reviewe

Dissociative electron transfer to diphenyl-substituted bicyclic endoperoxides : the effect of molecular structure on the reactivity of distonic radical anions and determination of thermochemical parameters

The heterogeneous electron transfer reduction of the bicyclic endoperoxide 1,4-diphenyl-2,3-dioxabicyclo[2.2.1]hept-5-ene (4) was investigated in N,N-dimethylformamide at a glassy carbon electrode. The endoperoxide reacts by a concerted dissociative ET mechanism resulting in reduction of the O-O bond with an observed peak potential of −1.4 V at 0.2 V s−1. The major product (90% yield) resulting from the heterogeneous bulk electrolysis of 4 at −1.4 V with a rotating disk glassy carbon electrode is 1,4-diphenyl-cyclopent-2-ene-cis-1,3-diol with a consumption of 1.73 electrons per mole. In contrast, 1,4-diphenyl-2,3-dioxabicyclo[2.2.2]oct-5-ene (1), undergoes a two-electron reduction mechanism in quantitative yield. This difference in product yield between 1 and 4 is suggestive of a radical-anion mechanism, as observed with 1,4-diphenyl-2,3-dioxabicyclo-[2.2.2] octane (2) and 1,4-diphenyl-2,3-dioxabicyclo[2.2.1]heptane (3). Convolution potential sweep voltammetry is used to determine unknown thermochemical parameters of 4, including the O-O bond dissociation energy and the standard reduction potential and a comparison is made to the previously studied bicyclic endoperoxides 1–3 with respect to the effect of molecular structure on the reactivity of distonic radical anions.peer-reviewe

Fourth annual Science in the House exhibition at the new parliament building

Members of Parliament, the House of Representatives and researchers were in attendance at the 4th annual Science in the House exhibition in the New Parliament Building in Valletta at noon of Thursday 24th September 2015. The event was inaugurated under the auspices of the Off ce of the Speaker by Ray Scicluna. Following comments by Prof. Alex Felice, speeches were presented by MPs Deborah Schembri and Claudio Grech. A few comments were made on behalf of the Faculty of Science by Prof. Emmanuel Sinagra to commemorate the 100th anniversary of the founding of the Faculty of Science at the University of Malta. The formal opening of the event concluded with enlightening words from the University Rector, Prof. Juanito Camilleri. The exhibition consisted of 12 posters representative of various research projects at the University of Malta from the Faculties of Science, Medicine and Surgery, Dental Surgery and Health Sciences. A commemorative poster was also dis played by the Faculty of Science to celebrate its 100th anniversary, which coincides with the centennial of Einstein's theory of relativity. Science in the House is organised by the Malta Chamber of Scientists, the University Research Trust (RIDT) and the Science in the City, European Researchers' Night consortium. Science in the City, European Researchers Night is mainly funded by the EU Marie Sklodowska-Curie Action of the Horizon 2020 (H2020) Programme. It is recognised by Europe for Festivals, Festivals for Europe (EFFE).peer-reviewe

Kinetics of the photoinduced dissociative reduction of the model alkyl peroxides di-tert-butyl peroxide and ascaridole

Rate constants for the reaction between excited singlet state aromatic donors and the dialkyl peroxide, di-tert-butyl peroxide (DTBP), and the bicyclic endoperoxide, ascaridole (ASC), were measured in acetonitrile using fluorescence quenching techniques. The rate constants, measured with 18 different aromatic donors by Stern-Volmer quenching, range from 9.2 109 to 4.4 106 M -1 s -1 . Using accurately measured standard reduction potentials for the peroxides, the driving force for photoinduced electron transfer is predicted to be thermodynamically feasible over the entire range of excited donors ranging from 49 to 10 kcal mol-1 for ASC and 38 to 2 kcal mol-1 for DTBP. However, when the photoinduced kinetics are combined with previously measured electron transfer kinetics by homogeneous redox catalysis with ground state radical-anion donors, a smooth parabolic correlation for a dissociative electron transfer mechanism is not observed. Rather, a discontinuity is observed between the photochemical and electrochemical data sets with the rate constants with singlet excited states donors being over two orders of magnitude larger than the ground state kinetics at the same driving force. The discrepancy is examined considering the importance of attractive interaction between fragments in the dissociative photoinduced electron transfer reactions.peer-reviewe

Proceedings of Science in the House

Celebrating its 5th anniversary, this year's Science in the House exhibition was a most memorable occasion. The event was held on Thursday 29th September at 11:00 am in the main foyer of the Parliament Building in Valletta. The event commenced with opening remarks from Prof. Alex Felice, chairman of the Science in the City/European Researchers' Night consortium followed by a distinguished list of speakers including Prof. Alfred Vella, Rector of the University of Malta, the Hon. Evarist Bartolo M.P., Minister for Education and Employment, and the Hon. Anglu Farrugia M.P., Speaker of the House of Representatives, Parliament of Malta. This year's event showcased a selection of research projects on neuroscience and brain research in addition to the regular compliment of posters from across various research disciplines. A set of four posters on the neuroscience theme presented research on the use of stereo-electroencephalography (EEG), the treatment of epilepsy with light, biochemical studies of autism and research related to depression, addition and epilepsy. Science in the House is organised by the Malta Chamber of Scientists, the RIDT and the Science in the City/European Researchers' Night consortium and part funded by the EU Marie Sklodowska-Curie Action of the Horizon 2020 (H2020) Programme.peer-reviewe

Optical sensing and switching with designed molecules

Abstract: Some of the recent research in optical sensor and switch molecules at Queen’s University of Belfast is outlined. The ion-induced absorption spectral changes of molecules with ICT (Internal Charge Transfer) excited states are used to demonstrate superposed logic where multiple logic configurations are simultaneously observable. Similar spectral effects in multi-receptor structures give rise to XOR logic. The ion-induced luminescent spectral changes of molecules with ICT excited states can be combined with the phenomenon of Photoinduced Electron Transfer (PET) to exemplify tristable systems. Insights can also be gained into the luminescence effects initiated in designed molecules by transition metal ions in non-aqueous media. The ion-induced luminescent spectral changes of PET systems with one or two receptors display YES and AND logic respectively. The latter yield coincidence sensors for the direct detection of ion pairs. Overall, interesting optical sensors and switches can be produced from rather small molecules when the latter are fitted with ion-receptors.peer-reviewe

Synthesis and spectrophotometric studies of heterocyclic bay-substituted naphthalenediimide colorimetric pH indicators

Four naphthalenediimide colorimetric pH indicators were synthesized with N,N-dimethylethyleneamine at the imide positions and with 5- to 7-membered heterocyclic rings at the bay positions, namely pyrrolidine, morpholine, piperidine and azepane. The pH indicators are constructed in a modular receptor–spacer–fluorophore–spacer–receptor format based on a photoinduced electron transfer (PET) design. The compounds were studied by UV–visible absorption and steady-state fluorescence spectroscopy in 1:1 (v/v) methanol/water. Brilliant colour changes are observed between pH 2 and 4 due to an internal charge transfer (ICT) mechanism. Fluorescence turn-on enhancements range from 10–37 fold; however, the maximum fluorescence quantum yield in the presence of acid is <0.004, which is below naked eye detection. Hence, from the viewpoint of a human observer, these chemosensors function as colorimetric YES logic gates, and fluorimetric PASS 0 logic gates.peer-reviewe