The identification and origin of N-H group overtone and combination bands in the near infrared spectra of 2-thiopyrrole-l,2-dicarboximides

Abstract

Near infrared spectra (4000-12000 cm^-1) of 2-thiopyrrole-l,2-dicarboximide (TPH) and its N-deuterated analogue were measured in polycrystalline form at different temperatures between 410 K and 273 K. Spectra in solution were recorded as a function of concentration and temperature. The prominent bands so obtained could be interpreted in terms of overtone and combination bands of the N-H(D) and C-O groups modes. The results in CHCl₃ and CC1₄ solutions allowed differentiation between hydrogen bonded and nonhydrogen bonded bands. A comparison of cubic potential constant K₃, mechanical anharmonicity ω_eχ_e and electrical anharmonicity μ₂/μ₁ for the stretching bands indicates that these constants are not affected much by N-deuteration.