The Raman spectrum of thiourea–oxocarbon adducts

Authors

  • José Guilherme S. Lopes,

    1. Laboratório de Espectroscopia Molecular, Instituto de Química, Universidade de São Paulo, CP 26077, 05513-970, São Paulo, SP, Brazil
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  • Luiz Fernando C. de Oliveira,

    1. Núcleo de Espectroscopia e Estrutura Molecular, Departamento de Química, Instituto de Ciências Exatas, Universidade Federal de Juiz de Fora, Juiz de Fora, MG, 36036-330, Brazil
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  • Howell G. M. Edwards,

    1. Department of Chemical and Forensic Sciences, University of Bradford, Bradford, West Yorkshire, BD7 1DP, UK
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  • Paulo S. Santos

    Corresponding author
    1. Laboratório de Espectroscopia Molecular, Instituto de Química, Universidade de São Paulo, CP 26077, 05513-970, São Paulo, SP, Brazil
    • Laboratório de Espectroscopia Molecular, Instituto de Química, Universidade de São Paulo, CP 26077, 05513-970, São Paulo, SP, Brazil.
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Abstract

The thiourea/squarate/tetraethylammonium adduct and the thiourea/croconate adduct were investigated by Raman spectroscopy. The former had been previously investigated by X-ray crystallography which revealed an extended network built from squarate and thiourea, connected by hydrogen bonding. The assignment of the vibrational modes in the thiourea/squarate adduct was facilitated by the preparation of the species containing deuterated thiourea. The vibrational shifts observed in the spectrum of the adducts indicate that the involved hydrogen bonds are only of moderate strength. In addition, the well-known Jahn–Teller pattern present in the Raman spectrum of oxocarbon anions is also observed to a great extent in the spectra of their thiourea adducts. Copyright © 2004 John Wiley & Sons, Ltd.

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