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The Chemical Educator

ISSN: 1430-4171 (electronic version)

Table of Contents

Abstract Volume 16 (2011) pp 114-115

Linkage Isomerization in Co(III) Complexes Induced by Sunlight. A Second-Year Undergraduate Laboratory Experiment

Julio J. Criado, Juan L. Manzano, Emilio Rodríguez-Fernández*, Raquel Trujillano, and Miguel A. Vicente

Department of Inorganic Chemistry, Faculty of Chemistry, University of Salamanca, E-37008-Salamanca. Spain,
Received January 12, 2011. Accepted March 1, 2011.

Published: 25 March 2011

Abstract. In this experiment, the easy isomerization from the nitro complex [Co(NO2)(NH3)5]Cl2 to the nitrito isomer [Co(ONO)(NH3)5]Cl2, by exposure to sunlight is reported. The process is also monitored by the changes in the infrared spectra that are associated with the rearrangement of the ligand from the nitro- to the nitrito-isomer. The infrared spectra were supplemented by visible spectra, comparing the solution spectra of pure, freshly-prepared isomer and those of samples irradiated for several periods of time. This is a very useful tool as it allows students to relate color changes to the isomerization of the complex.

Key Words: Laboratories and Demonstrations; inorganic chemistry; cobalt; linkage isomers; hands-on learning; IR spectroscopy; photochemistry; second-year undergraduate; UV-Vis spectroscopy

(*) Corresponding author. (E-mail:

Article in PDF format (34 KB) HTML format

Supporting Materials:

Compounds preparation procedure. IR and visible spectra are available (130 KB).

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