Publications by authors named "Nimal Gunaratne"

A recurring dream of molecular recognition is to create receptors that distinguish between closely related targets with sufficient accuracy, especially in water. The more useful the targets, the more valuable the dream becomes. We now present multianionic trimeric cyclophane receptors with a remarkable ability to bind the iconic (bipyridine)Ru(II) (with its huge range of applications) while rejecting the nearly equally iconic (phenanthroline)Ru(II).

View Article and Find Full Text PDF

To date, the high cost of supplying UV irradiation has prevented the widespread application of UV photolysis and titanium dioxide based photocatalysis in removing undesirable organics in the water treatment sector. To overcome this problem, the use of UV-LEDs (365 nm) for photolysis and heterogeneous photocatalysis applying TiO coated glass beads under UV-LED illumination (365 nm) in a pilot scale reactor for the elimination of Microcystis aeruginosa PCC7813 and four microcystin analogues (MC-LR, -LY, -LW, -LF) with a view to deployment in drinking water reservoirs was investigated. UV-A (365 nm) photolysis was shown to be more effective than the UV/TiO photocatalytic system for the removal of Microcystis aeruginosa cells and microcystins.

View Article and Find Full Text PDF

While phthalate esters are commonly used as plasticizers to improve the flexibility and workability of polymeric materials, their presence and detection in various environments has become a significant concern. Phthalate esters are known to have endocrine-disrupting effects, which affects reproductive health and physical development. As a result, there is now increased focus and urgency to develop effective and energy efficient technologies capable of removing these harmful compounds from the environment.

View Article and Find Full Text PDF

A bis-oxazoline ligand has been complexed using Cu(ii) and Zn(ii) trifluoromethanesulfonate and a range of chiral ionic liquid (CIL) additives based on natural products were used as a co-catalyst for a Diels-Alder reaction. The catalytic performance of these systems was compared for the asymmetric Diels-Alder reaction between N-acryloyloxazolidinone and cyclopentadiene with and without the presence of a CIL additive. In the absence of the CIL, both catalysts resulted in low enantioselectivities in conventional solvents and ionic liquids.

View Article and Find Full Text PDF

Toluene dioxygenase (TDO)-catalysed sulfoxidation, using Pseudomonas putida UV4, was observed for the thiophene substrates 1A-1N. The unstable thiophene oxide metabolites, 6A-6G, 6K-6N, spontaneously dimerised yielding the corresponding racemic disulfoxide cycloadducts 7A-7G, 7K-7N. Dimeric or crossed [4 + 2] cycloaddition products, derived from the thiophene oxide intermediates 6A and 6D or 6B and 6D, were found when mixtures of thiophene substrates 1A and 1D or 1B and 1D were biotransformed.

View Article and Find Full Text PDF