A Chromo-Fluorogenic Synthetic Canary for CO Detection Based on a Pyrenylvinyl Ruthenium(II) Complex

The chromo-fluorogenic detection of carbon monoxide in air has been achieved using a simple, inexpensive system based on ruthenium(II). This probe shows exceptional sensitivity and selectivity in its sensing behavior in the solid state. A color response visible to the naked eye is observed at 5 ppb of CO, and a remarkably clear color change occurs from orange to yellow at the onset of toxic CO concentrations (100 ppm) in air. Even greater sensitivity (1 ppb) can be achieved through a substantial increase in turn-on emission fluorescence in the presence of carbon monoxide, both in air and in solution. No response is observed with other gases including water vapor. Immobilization of the probe on a cellulose strip allows the system to be applied in its current form in a simple optoelectronic device to give a numerical reading and/or alarm.Financial support from the Spanish Government (project MAT2012-38429-C04) and the Generalitat Valenciana (project PROMETEO/2009/016) is gratefully acknowledged. M.E.M. is grateful to the Spanish Ministerio de Ciencia e Innovacion for an FPU grant. J.D.E.T.W.-E. and A.T. acknowledge the Leverhulme Trust for a grant (RPG-2012-634).Moragues Pons, ME.; Toscani, A.; Sancenón Galarza, F.; Martínez-Máñez, R.; White, A.; Wilton-Ely, JDET. (2014). A Chromo-Fluorogenic Synthetic Canary for CO Detection Based on a Pyrenylvinyl Ruthenium(II) Complex. Journal of the American Chemical Society. 136(34):11930-11933. https://doi.org/10.1021/ja507014aS11930119331363

Palladium Complexes Derived from Waste as Catalysts for C-H Functionalisation and C-N Bond Formation

Three-way catalysts (TWCs) are widely used in vehicles to convert the exhaust emissions from internal combustion engines into less toxic pollutants. After around 8–10 years of use, the declining catalytic activity of TWCs causes them to need replacing, leading to the generation of substantial amounts of spent TWC material containing precious metals, including palladium. It has previously been reported that [NnBu4]2[Pd2I6] is obtained in high yield and purity from model TWC material using a simple, inexpensive and mild reaction based on tetrabutylammonium iodide in the presence of iodine. In this contribution, it is shown that, through a simple ligand exchange reaction, this dimeric recovery complex can be converted into PdI2(dppf) (dppf = 1,1′-bis(diphenylphosphino)ferrocene), which is a direct analogue of a commonly used catalyst, PdCl2(dppf). [NnBu4]2[Pd2I6] displayed high catalytic activity in the oxidative functionalisation of benzo[h]quinoline to 10-alkoxybenzo[h]quinoline and 8-methylquinoline to 8-(methoxymethyl)quinoline in the presence of an oxidant, PhI(OAc)2. Near-quantitative conversions to the desired product were obtained using a catalyst recovered from waste under milder conditions (50 °C, 1–2 mol% Pd loading) and shorter reaction times (2 h) than those typically used in the literature. The [NnBu4]2[Pd2I6] catalyst could also be recovered and re-used multiple times after the reaction, providing additional sustainability benefits. Both [NnBu4]2[Pd2I6] and PdI2(dppf) were also found to be active in Buchwald–Hartwig amination reactions, and their performance was optimised through a Design of Experiments (DoE) study. The optimised conditions for this waste-derived palladium catalyst (1–2 mol% Pd loading, 3–6 mol% of dppf) in a bioderived solvent, cyclopentyl methyl ether (CPME), offer a more sustainable approach to C-N bond formation than comparable amination protocols

Facile Preparation of Drug-Loaded Tristearin Encapsulated Superparamagnetic Iron Oxide Nanoparticles Using Coaxial Electrospray Processing

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Chromo-fluorogenic probes for carbon monoxide detection

[EN] The sensing of carbon monoxide (CO) using electrochemical cells or semiconducting metal oxides has led to inexpensive alarms for the home and workplace. It is now recognised that chronic exposure to low levels of CO also poses a significant health risk. It is perhaps surprising therefore that the CO is used in cell-signalling pathways and plays a growing role in therapy. However, the selective monitoring of low levels of CO remains challenging, and it is this area that has benefited from the development of probes which give a colour or fluorescence response. This feature article covers the design of chromofluorogenic probes and their application to CO sensing in air, solution and in cells.The authors wish to express their gratitude to the Spanish Government (project MAT2012-38429-CO4 and MAT2015-64139-C4-1) and Generalitat Valenciana (project PROMETEOII/2014/047) for their support. C. M.-H. thanks the Spanish Ministry of Economy and Competitiveness for her grant. The Leverhulme Trust is gratefully acknowledged for a studentship to A. T. (RPG-2012-634). The Imperial College Global Engagements fund is thanked by J. D. E. T. W.-E. for provision of a travel grant.Marín-Hernández, C.; Toscani, A.; Sancenón Galarza, F.; Wilton-Ely, JDET.; Martínez-Máñez, R. (2016). Chromo-fluorogenic probes for carbon monoxide detection. Chemical Communications. 52(35):5902-5911. https://doi.org/10.1039/c6cc01335jS59025911523