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|Title:||Sensitized terbium (III) macrocyclic-phthalimide complexes as luminescent pH switches||Author(s):||Bligh, Annie Sim Wan||Author(s):||Chen, G.
Wardle, N. J.
Chatterton, N. P.
|Issue Date:||2013||Publisher:||Royal Society of Chemistry||Journal:||Dalton Transactions||Volume:||42||Issue:||39||Start page:||14115||End page:||14124||Abstract:||
Four new macrocyclic-phthalimide ligands were synthesised via the coupling of N-(3-bromopropyl)phthalimide either to cyclen (1,4,7,10-tetraazacyclododecane) itself or its carboxylate-functionalized analogues, and photophysical studies were carried out on their corresponding Tb(III) complexes in aqueous media as a function of pH. Luminescence intensities of Tb·L1a1a–Tb·L3a3a were in ‘switched off’ mode under acidic conditions (pH < 4), and were activated on progression to basic conditions as the phthalimido functions therein were hydrolysed to their corresponding phthalamates Tb·L1b1b1b–Tb·L3b3b3b. Emission of phthalamate-based macrocyclic Tb(III) complexes Tb·L1b1b1b–Tb·L3b3b3b was in ‘switched on’ mode between pH 4 and 11, exhibiting high quantum yields (Φ) and long lifetimes (τ) of the order of milliseconds at pH ∼ 6. Tb(III) emissions were found to decline with increasing number of chromophores. The values of Φ and τ were 46% and 2.4 ms respectively for Tb·L1b1b at pH ∼ 6 when activated. This is the best pH-dependent sensor based on a Tb(III) complex reported to date, benefiting from the macrocyclic architecture of the ligand.
|URI:||https://repository.cihe.edu.hk/jspui/handle/cihe/1504||DOI:||10.1039/c3dt51236c||CIHE Affiliated Publication:||No|
|Appears in Collections:||HS Publication|
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