Res. Chem. Intermed.
, Vol. 32, No. 7, pp. 637–645 (2006)
Also available online - www.vsppub.com
Photophysical characteristics and density functional theory
calculations of indole 2-carboxylic acid in the presence
of mercurous ions
, SUDHIR KAPOOR
, SHWETA HEGDE
and TULSI MUKHERJEE
Radiation Chemistry & Chemical Dynamics Division, Bhabha Atomic Research Centre,
Mumbai 400 085, India
Department of Chemistry, University of Pune, Pune 411 007, India
Leibniz-Institut für Oberﬂächenmodiﬁzierung, Permoserstrasse 15, D-04318 Leipzig, Germany
Received 24 July 2005; accepted 17 October 2005
Abstract—Many photo-physical studies have been reported for the detection of Hg
we present the effect of Hg
ions on the absorption and ﬂuorescence of indole-2-carboxylic acid
(I2C). Experimental evidence, supported by density functional theory B3LYP/LANL2DZ/PCM, for
the formation of a I2C-Hg
complex, is reported for the ﬁrst time. It was observed that I2C forms a
ground-state complex with Hg
ions in a ratio of 3:1. The possibility of I2C to be used as a selective
novel chemical sensor for the spectrophotometric detection of mercurous ions is described.
Keywords: Fluorescence; photo-induced electron transfer; complex formation.
Indole carboxylic acids are known as plant growth regulators. Indole acids are
known to coordinate plant growth from the seedling stage to fruit ripening .
Plants are exposed to an environment of soil, water and air. Contamination of
biospheres by trace metals due to human activities  introduces these metals
to plants and microbial systems, causing them to undergo metal stress. Natural
evolution has also incorporated many metals into essential biological functions and
metallic elements play a crucial role in living systems . Positively charged
metal ions tend to be soluble in biological ﬂuids. It is this cationic form due to
which metals play their role in biology. Metals are electron deﬁcient, whereas most
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