Metal-ion chelation and sensing using a self-assembled molecular photoswitch

Wang, Zhenxin, Cook, Michael J., Nygård, Anne-Mette and Russell, David A. (2003) Metal-ion chelation and sensing using a self-assembled molecular photoswitch. Langmuir, 19 (9). pp. 3779-3784. ISSN 0743-7463

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The novel (pyridylazo)phenol derivative 8-[4-(2-pyridylazo)phenoxy]octyl disulfide (1) has been designed and synthesized for the formation of a monolayer film on gold-coated optical waveguides via the technique of self-assembly. The photoinduced trans to cis isomerization of the self-assembled monolayer of 1 (1 SAM) and its interaction with transition-metal ions have been studied by spectroscopic (UV-visible and reflection absorption infrared) and electrochemical methods. The 1 SAM in the trans isomeric form provides a bidentate ligand that can chelate metal ions, such as Ni2+ and Co2+, and results in a strong absorption in the UV-visible absorption spectrum at 433 nm, a red shift of 77 nm from the maximum absorption wavelength for the unchelated 1 SAM. Following irradiation with waveguided UV light (? = 365 nm) via the evanescent field, the 1 SAM photoisomerizes to the cis form. No metal chelation was observed with the cis isomer of the 1 SAM. The photoinduced processes are reversible; the cis form SAM is converted to the trans form SAM after visible light irradiation (? = 439 nm), again via the evanescent wave. The trans 1 SAM was used to detect Ni2+ in the range 9.6 × 10-5-2.44 × 10-3 M.

Item Type: Article
Faculty \ School: Faculty of Science > School of Chemistry
UEA Research Groups: Faculty of Science > Research Groups > Physical and Analytical Chemistry (former - to 2017)
Depositing User: Rachel Smith
Date Deposited: 21 Jan 2011 16:49
Last Modified: 24 Oct 2022 03:05
DOI: 10.1021/la026792n

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