Structural and Reactivity Analyses of Nitrofurantoin–4-dimethylaminopyridine Salt Using Spectroscopic and Density Functional Theory Calculations

Crystals

KhaledH. Assi¹  VenuR. Vangala¹  Poonam Tandon²  Karnica Srivastava²  Anuradha Shukla²  Eram Khan²  Debraj Gangopadhyay² 

[1] Centre for Pharmaceutical Engineering Science and School of Pharmacy and Medical Sciences, University of Bradford, Bradford BD7 1DP, UK;Department of Physics, University of Lucknow, Lucknow 226 007, India;

关键词: Nitrofurantoin–4-dimethylaminopyridine (NF-DMAP) salt;    DFT study;    HOMO-LUMO;    reactivity descriptors;    hydrogen bonding;   

DOI  :  10.3390/cryst9080413

来源: DOAJ

【 摘 要 】

Pharmaceutical salt, nitrofurantoin–4-dimethylaminopyridine (NF-DMAP), along with its native components NF and DMAP are scrutinized by FT-IR and FT-Raman spectroscopy along with density functional theory so that an insight into the H-bond patterns in the respective crystalline lattices can be gained. Two different functionals, B3LYP and wB97X-D, have been used to compare the theoretical results. The FT-IR spectra obtained for NF-DMAP and NF clearly validate the presence of C33–H34⋅⋅⋅O4 and N23–H24⋅⋅⋅N9 hydrogen bonds by shifting in the stretching vibration of –NH and –CH group of DMAP⁺ towards the lower wavenumber side. To explore the significance of hydrogen bonding, quantum theory of atoms in molecules (QTAIM) has been employed, and the findings suggest that the N23–H24⋅⋅⋅N9 bond is a strong intermolecular hydrogen bond. The decrement in the HOMO-LUMO gap, which is calculated from NF → NF-DMAP, reveals that the active pharmaceutical ingredient is chemically less reactive compared to the salt. The electrophilicity index (ω) profiles for NF and DMAP confirms that NF is acting as electron acceptor while DMAP acts as electron donor. The reactive sites of the salt are plotted by molecular electrostatic potential (MEP) surface and calculated using local reactivity descriptors.

【 授权许可】

Unknown