title: Formation of p-cresol:piperazine complex in solution monitored by spin-lattice relaxation times and pulsed field gradient NMR diffusion measurements.
abstract: A study of the nature of the anthelmintic p-cresol:piperazine complex in chloroform solution has been conducted using different NMR techniques: self-diffusion coefficients using DOSY; NOE, NULL, and double-selective T1 measurements to determine inter-molecular distances; and selective and non-selective T1 measurements to determine correlation times. The experimental results in solution and CP-MAS were compared to literature X-ray diffraction data using molecular modeling. It was shown that the p-cresol:piperazine complex exists in solution in a very similar manner as it does in the solid state, with one p-cresol molecule hydrogen bonded through the hydroxyl hydrogen to each nitrogen atom of piperazine. The close correspondence between the X-ray diffraction data and the inter-proton distances obtained by NULL and double selective excitation techniques indicate that those methodologies can be used to determine inter-molecular distances in solution.
mesh_terms: D001665:Binding Sites; D002247:Carbon Isotopes; D002725:Chloroform / Q000737:chemistry*; D003408:Cresols / Q000737:chemistry*; D003461:Crystallography / Q000379:methods*; D006860:Hydrogen Bonding; D046911:Macromolecular Substances; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008968:Molecular Conformation; D000077489:Piperazine; D010879:Piperazines / Q000737:chemistry*; D011522:Protons; D012996:Solutions; D013113:Spin Labels
chemical_list: D002247:Carbon Isotopes; D003408:Cresols; D046911:Macromolecular Substances; D010879:Piperazines; D011522:Protons; D012996:Solutions; D013113:Spin Labels; C032538:4-cresol; D000077489:Piperazine; D002725:Chloroform