Phosphorescent chemosensors

Zhao, Q., Liu, S.J., Li, F.Y., et al. (2008) Highly selective phosphorescent chemosensor for fluoride based on an iridium(lll) complex containing arylborane units. Inorganic Chemistry, 47, 9256-9264. 

Homocysteine has a unique role within physiologic matrices because it is an important amino acid containing a free thiol moiety. Detection of homocysteine from other amino acids is therefore important. A selective phosphorescence chemosensor for this aim was developed based on the reaction shown in Fig. 31 [127]. Upon addition of homocysteine to a semiaqueous solution of 61, a color change from orange to yellow and a luminescent variation from deep red to green were evident to the naked eye. This can be attributed to formation of a thiazinane group by selective reaction of the aldehyde group of 61 with homocysteine. 

Bissel and de Silva have created a H+ chemosensor by cleverly augmenting Scheme 1 with a PET relay mechanism. The system design is depicted in Fig. 14. The long-lived, room temperature phosphorescence of bromonaphtha-lene is quenched by PET from an attached amine moiety (1) [255], Embedded... 

Figure 15 Addition of alcohols to a complex formed between reporter and CD provides the necessary protection to avoid O2 quenching of room temperature phosphorescence from the reporter site. The scheme describes the operation of chemosensors described in Refs. 301 and 302.

Nolte et al. have attached a CD to each pyridine ring of a [Ru(bpy)2+] core to generate the impressively large superstructures of 62 and 63 [396], The metal center is so insulated from the external environment by the CD periphery that oxygen is unable to quench MLCT phosphorescence. 63 was the focus of chemosensor investigations because its luminescence is very intense, exceeding that of the native Ru(bpy)2+ complex. Addition of the electron ac-... 

Cyclodextrins have been used for enhancing the phosphorescence of guests by encapsulation [12]. de Silva et al. employed cyclodextrins as transparent shields to protect the phosphor molecule sterically from contact with its environment (especially O2) while allowing access to photons. Sensing remains viable because the proton receptor module is not enveloped (Figure 9) [13]. The authors used this system as a phosphorescent PET (photoinduced electron transfer) chemosensor for... 

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