Science News
from research organizations

Chemistry professor discovers color sensor compound for anions

Date:
August 27, 2015
Source:
University of Huddersfield
Summary:
A chemistry professor has uncovered a major development in the study of anions, negatively-charged molecules such as chloride, bromide and nitrate, which have strategic roles within the human body. These molecules can also act as pollutants, some of which are vital to our health whilst others might actually harm us. The chemistry behind the detection of anions is still in its infancy and an easy, reliable and robust method of detection has eluded chemists... until now.
Share:
FULL STORY

The green circular assembly formed from self-assembly with nitrate ions.
Credit: Image courtesy of University of Huddersfield

A chemistry professor at the University of Huddersfield has uncovered a major development in the study of anions, negatively-charged molecules such as chloride, bromide and nitrate, which have strategic roles within the human body. These molecules can also act as pollutants, some of which are vital to our health whilst others might actually harm us. The chemistry behind the detection of anions is still in its infancy and an easy, reliable and robust method of detection has eluded chemists... until now.

The University of Huddersfield's Professor Craig Rice has recently discovered a compound that undergoes a colorimetric response to a whole host of different ions. However, the most remarkable facet of the chemistry is that the detecting species is not made directly by the scientist, but because the response spontaneously 'self-assembles' to give a sensor for each specific anion.

"A colorimetric response, which determines the concentration of a chemical element or compound through the aid of a colour reagent, is far more desirable," said Professor Rice, "because as it's easy to interpret and in this newly-discovered system, a large range of colours are observed ions. For example, anions such as nitrate are brown, sulphate yellow and perchlorate blue."

Now, Professor Rice's discovery could lead to a practical colorimetric system for detecting anions.

The phosphate yellow structure pictured is an X-ray of a self-assembled capsule, containing 18 separate species, comprising six organic molecules, six copper ions and six phosphate anions. The phosphate anions are held within the self-assembled system and it is this that gives rise to all the different colours observed with different anions.

In the chemistry, the resultant self-assembled system -- the growing of a large complex molecule from small components -- was dependent on which anion was being investigated.

"We found that when we were investigating phosphate," said Professor Rice, "a capsule was formed from 12 different molecules and it contains six phosphate anions, whereas a nitrate comprised a circular assembly with eight nitrate anions. The phosphate species was yellow and the nitrate green. As a result, a sensor specific to each ion was grown by the molecule itself without any input from the scientist.


Story Source:

Materials provided by University of Huddersfield. Note: Content may be edited for style and length.


Journal Reference:

  1. Robert A. Faulkner, Lindsay P. Harding, Joshua Higginson, Craig R. Rice, Christopher Slater. Formation of a Dimer of Trinuclear Helicates which Encapsulates an Array of Six Hydrogen-Bonded Anions. Angewandte Chemie International Edition, 2014; 53 (49): 13540 DOI: 10.1002/anie.201407645

Cite This Page:

University of Huddersfield. "Chemistry professor discovers color sensor compound for anions." ScienceDaily. ScienceDaily, 27 August 2015. <www.sciencedaily.com/releases/2015/08/150827121958.htm>.
University of Huddersfield. (2015, August 27). Chemistry professor discovers color sensor compound for anions. ScienceDaily. Retrieved May 26, 2017 from www.sciencedaily.com/releases/2015/08/150827121958.htm
University of Huddersfield. "Chemistry professor discovers color sensor compound for anions." ScienceDaily. www.sciencedaily.com/releases/2015/08/150827121958.htm (accessed May 26, 2017).

RELATED STORIES