Photochemistry of the cis- and trans-Dichlorobisethylenediamine Chromium(III) Cations in Acidic Aqueous Solutions. Observation of a Stereochemical Change in Photoaquation

The photoreactions of cis- and trans-[CrCl 2 (en) 2 ] + have been investigated in acidic aqueous solution at pH 3 and 0 °C. On photolysis in the ligand field bands the cis isomer was found to undergo mainly ethylenediamine aquation, apparently to a thermally unstable monodentate protonated ethylened...

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Bibliographic Details
Published inCanadian journal of chemistry Vol. 49; no. 9; pp. 1524 - 1528
Main Authors Kirk, A. D, Moss, K. C, Valentin, J. G
Format Journal Article
LanguageEnglish
Published Ottawa, Canada NRC Research Press 01.05.1971
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Summary:The photoreactions of cis- and trans-[CrCl 2 (en) 2 ] + have been investigated in acidic aqueous solution at pH 3 and 0 °C. On photolysis in the ligand field bands the cis isomer was found to undergo mainly ethylenediamine aquation, apparently to a thermally unstable monodentate protonated ethylenediamine complex, with a quantum yield of 0.13. In addition chloride aquation occurred with . In contrast, the trans isomer underwent exclusive chloride aquation with quantum yield 0.32. The results are qualitatively, but not quantitatively, in agreement with predictions of Adamson's empirical rules. It was found that for trans-[CrCl 2 (en) 2 ] + photolysis, the reaction product [CrCl(H 2 O)(en) 2 ] 2+ was produced at least 70% in the cis configuration.
ISSN:0008-4042
1480-3291
DOI:10.1139/v71-248