title: The Elusive Antiaromaticity of Maleimides and Maleic Anhydride: Enthalpies of Formation of N-Methylmaleimide, N-Methylsuccinimide, N-Methylphthalimide, and N-Benzoyl-N-methylbenzamide.
abstract: In order to understand the antiaromaticity of maleimides, the enthalpies of formation and sublimation of N-methylmaleimide, N-methylsuccinimide, N-methylphthalimide, and N-benzoyl-N-methylbenzamide were measured. The numerical values of enthalpies of formation for these compounds in the solid state are -329.3 +/- 1.4, -469.8 +/- 1.6, -325.0 +/- 2.1, and -239.6 +/- 3.8 kJ mol(-)(1), respectively, while the corresponding values in the gaseous state are -256.0 +/- 1.5, -389.7 +/- 1.6, -233.9 +/- 2.2, and -119.5 +/- 3.8 kJ mol(-)(1), respectively. The values of enthalpies of sublimation for the same compounds are 73.3 +/- 0.5, 80.1 +/- 0.3, 91.1 +/- 0.5, and 120.1 +/- 0.4 kJ mol(-)(1), respectively. We find that the antiaromaticity of maleimides is only modest.
authors.affiliation: Institute of Physical Chemistry "Rocasolano", CSIC, Serrano 119, 28006 Madrid, Spain, and Department of Chemistry and Biochemistry, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, Maryland 21250.
authors.forename: María Victoria
authors.initials: MV
authors.lastname: Roux
authors.forename: Pilar
authors.initials: P
authors.lastname: Jiménez
authors.forename: Maria Ángeles
authors.lastname: Martín-Luengo MÁ
authors.forename: Juan Z.
authors.initials: JZ
authors.lastname: Dávalos
authors.forename: Zhiyuan
authors.initials: Z
authors.lastname: Sun
authors.forename: Ramachandra S.
authors.initials: RS
authors.lastname: Hosmane
authors.forename: Joel F.
authors.initials: JF
authors.lastname: Liebman