Investigation of rotameric conformations of substituted imidazo-[1, 2-a]pyrazine: experimental and theoretical approaches. Issue 18 (7th March 2018)

• Record Type: Journal Article
• Authors: Kumar, Gulshan; Goel, Richa; Paul, Kamaldeep; Luxami, Vijay
• Is Part Of: RSC advances. Volume 8:Issue 18(2018)
• Page Start: 9707
• Page End: 9717
• Publication Date: 2018-03-07
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/c7ra13617j
• Languages: English
• ISSNs: 2046-2069

Abstract

Abstract : The different rotameric conformations of imidazo-[1, 2- a ]pyrazine have been synthesized and characterized by means of different experimental techniques, such as NMR, FTIR, and absorption spectroscopy and quantum chemical calculations. Abstract : The different rotameric conformations of imidazo-[1, 2- a ]pyrazine have been synthesized and characterized by means of different experimental techniques, such as NMR, FTIR, and absorption spectroscopy and quantum chemical calculations. The different conformations were stabilized by hydrogen bonds, such as OH⋯N, ArH⋯N and ArH⋯ArH. The ground state optimizations and potential energy surface (PES) scanning profiles produced using density functional theory (DFT) show two stable rotameric forms for each molecule. The relative population of the conformations is affected by the strength of the hydrogen bonds. The calculated absorption spectra and isotopic shielding constants were acquired by time-dependent density functional theory (TD-DFT) and gauge invariant atomic orbitals (GIAO)-DFT, respectively. The strength of the hydrogen bonding interactions that resulted in the different conformations was studied by quantum theory of atoms in molecules (QTAIM).