title: Structural study of selected polyhalogenated benzimidazoles (protein kinase CK2 inhibitors) by nuclear quadrupole double resonance, X-ray, and density functional theory.
abstract: Protein kinase CK2 inhibitors, polyhalogenated benzimidazoles, have been studied experimentally in solid state by NMR-NQR double resonance and X-ray and theoretically by the density functional theory (DFT). Six resonance frequencies on (14)N have been detected and assigned to particular nitrogen sites in each polyhalogenated benzimidazole molecule. The effects of prototropic annular tautomerism and polymorphism related to stable cluster formation due to intermolecular hydrogen bonding interactions on the (14)N NQR parameters have been analyzed within the DFT and AIM (atoms in molecules) formalism. The studies suggest that all polyhalogenobenzimidazoles are isostructural and can exhibit polymorphism and that (14)N NQR is very sensitive to hydrogen bondings but less sensitive to the specific arrangement of the hydrogen bonded molecules. NQDR and DFT results suggest the presence of the prototropic annular tautomerism 50:50, which is in a good agreement with the X-ray and (1)H NMR data.
authors.affiliation: Faculty of Physics, Adam Mickiewicz University Umultowska 85, 61-614 Poznan, Poland. Jolanta.Latosinska@amu.edu.pl
authors.forename: J N
authors.initials: JN
authors.lastname: Latosińska
authors.forename: M
authors.initials: M
authors.lastname: Latosińska
authors.forename: J
authors.initials: J
authors.lastname: Seliger
authors.forename: V
authors.initials: V
authors.lastname: Zagar
authors.forename: J K
authors.initials: JK
authors.lastname: Maurin
authors.forename: A
authors.initials: A
authors.lastname: Orzeszko
authors.forename: Z
authors.initials: Z
authors.lastname: Kazimierczuk
mesh_terms: D001562:Benzimidazoles / Q000737:chemistry*; D003198:Computer Simulation; D018360:Crystallography, X-Ray; D009682:Magnetic Resonance Spectroscopy; D008956:Models, Chemical; D008958:Models, Molecular; D015394:Molecular Structure; D047428:Protein Kinase Inhibitors / Q000737:chemistry*; D011789:Quantum Theory
chemical_list: D001562:Benzimidazoles; D047428:Protein Kinase Inhibitors