title: Hydrogen bonding and stacking pi-pi interactions in solid 6-thioguanine and 6-mercaptopurine (antileukemia and antineoplastic drugs) studied by NMR-NQR double resonance spectroscopy and density functional theory.
abstract: A chemotherapeutic drug 6-thioguanine (2-amino-1,7-dihydro-6H-purine-6-thione, 6-TG) has been studied experimentally in the solid state by NMR-NQR double resonance and theoretically by the density functional theory. Fourteen resonance frequencies on (14)N have been detected and assigned to particular nitrogen sites in the 6-TG molecule. A valid assignment of NQR frequencies for 6-mercaptopurine (6-MP) has been proposed. The effects of molecular aggregations, related to intermolecular hydrogen bonding and stacking pi-pi interactions on the NQR parameters have been analyzed within the DFT and AIM (atoms in molecules) formalism for 6-TG and 6-mercaptopurine (6-MP). The so-called global reactivity descriptors have been calculated to compare the properties of molecules of 6-TG and 6-MP, to check the effect of -NH(2) group as well as to identify the differences in crystal packing.
authors: Faculty of Physics, Adam Mickiewicz University, Umultowska 85, 61-614 Poznań, Poland. Jolanta.Latosinska@amu.edu.pl
authors: J N
authors: JN
authors: Latosińska
authors: J
authors: J
authors: Seliger
authors: V
authors: V
authors: Zagar
authors: D V
authors: DV
authors: Burchardt
mesh_terms: D003198:Computer Simulation; D006860:Hydrogen Bonding; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D015122:Mercaptopurine / Q000737:chemistry*; D008956:Models, Chemical; D013866:Thioguanine / Q000737:chemistry*
chemical_list: D015122:Mercaptopurine; D013866:Thioguanine