Structure, dynamics, and substituent effects of sulfa-drugs and their model compounds by free jet rotational spectroscopy and model calculations

• Author(s): Nonato, Maybel
• Date: 2015
• Persistent ID: http://hdl.handle.net/10400.1/7845
• Origin: Sapientia - Universidade do Algarve
• Subject(s): Espectroscopia rotacional; Sulfamides; Domínio/Área Científica::Ciências Naturais::Ciências Químicas
• Document Type: Master thesis
• Language: English
• Advisor(s): Melandri, Sonia; Maris, Assimo
• Contributor(s): Sapientia

Description

Dissertação de mestrado, Inovação Quimica e Regulamentação, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2015

Sulfa-drug derivatives, such as Benzenesulfonamide (BSA), para-Toluenesulfonamide (p-TSA), ortho-Toluenesulfonamide (o-TSA), and Sulfanilamide (SAM), are widely used in the chemical industry. However, these polar organic compounds constitute emerging environmental concerns. Unfortunately, there is lack of eco-toxicological data for these substances but some insight can be obtained by analyzing the molecular structure and conformational properties of the compounds which can aid with the understanding of their biological mechanisms. Rotational spectroscopy coupled with high level theoretical calculations can supply these data. In this dissertation, the structural information and conformational properties of the sulfa-drug derivatives were obtained by a combined study of rotational spectroscopy in free jet expansions and quantum chemical calculations (B3LYP and MP2 at 6-311++G** level of theory). The effect of the added substituents (ortho/para-CH3 and para-NH2), in terms of structural parameters, were investigated as well since BSA is the molecular backbone of o-TSA, p-TSA, and SAM. Results showed that the four sulfa-drug derivatives favour the eclipsed conformation of the –NH2 and –SO2 groups but rationalization behind this preference varies among the compounds. Conversely, addition of –CH3 and –NH2 in the para position has no significant effects on the structural parameters of BSA but addition of ortho-CH3 brought some dramatic changes in the bond angles.

European Commission: scholarship funded within the Erasmus+ KA1 Programme, ref. 2013-0241 – Erasmus Mundus Joint Master Degree in Chemical Innovation and Regulation