Resumen de Transition metal complexes for chromo-fluorogenic detection of carbon monoxide in environmental and biomedical applications.
María Esperanza Moragues Pons
The present PhD thesis entitled "Transition metal complexes for chromo- fluorogenic detection of carbon monoxide in environmental and biomedical applications" is based on the use of Coordination Chemistry for the design and development of new chemical compounds capable of detecting carbon monoxide in air by colour and/or fluorencence changes. The first family of colorimetric probes reported in chapter 3 is based on hexacoordinated binuclear rhodium complexes with different triphenylphosphines and carboxylic acids as ligands. Complex A of formula [Rh2(C6H4PPh2)2(O2CCH3)2]·(HO2CCH3)2 is presented in first place as it features selective and highly sensitive CO detection both in solution and in air. 1n presence of CO a colour change from purple to yellow takes place, due to the axial coordination of CO. Throughout chapter 3, the work is extended with a collection of five rhodium (11) complexes B-F adsorbed on silica. The use of these as probes for CO detection is assessed through colour changes visible to the naked eye. Thirdly, the rhodium complexes are deposited on cellulose paper to improve its applicability in practical CO detection. Complex D [Rh2[(C6H4)P(C6H5)2]2(O2CCF3)2]· (CF3CO2H)2 is selected as the one with highest sensitivity to CO in this new support and it is introduced inside an opto-electronic system capable of quantifying CO present in air; through transduction of the complex colour change to an electrical signal, and this signal to a certain CO concentration value. Finally, bearing in mind the role of CO as a therapeutic and taking advantage of the reversibility of CO coordination in these rhodium complexes; dicarbonylic complexes A·(C0)2 and F·(C0)2 ([Rh2[(C6H4)P(C6H5)2]2(O2CCH3)2]·(CO)2 and [Rh2[(m- CH3C6H3)P(m-CH3C6H4)2]2(O2CCH3)2]·(CO)2), this is, the two complexes with slower CO releasing kinetics were selected as carbon monoxide releasing molecules (CO- RMs) to be used as inhibitors of indicators of cellular inflammation (see chapter 4). The second part of this PhD thesis deals with the synthesis of a collection of vinyl ruthenium and osmium complexes G-K functionalized with electron donor groups (pyrene, toluene and benzene) and an electron acceptor group (2,1,3- benzothiadiazole (BTD)). These are coloured complexes, as they feature one charge transfer band. 1n presence of CO, the BTD is displaced and a concomitant colour change is observed (see chapter 5). 1n a first step, fluorogenic detection of CO is enabled by the anchoring of pyrenylvinyl fluorophore as an electron donor ligand in ruthenium (11) complex G. 1n presence of CO and due to BTD displacement a fluorescence turn-on is achieved, being even visible to the naked eye. To conclude the second part of the thesis, four more complexes H-K (two of ruthenium and two of osmium) have been synthetized and used also for CO detection in air. Silica gel has also been used as support for the preparation of these probes. 1n the presence of CO displacement of the BTD (dye) occurs and the metallic probes display a colour change, enabling semiquantifive sensing of CO in air at different concentration ranges at which CO is highly toxic even for short exposures.
