title: NMR characterisation of structure in solvates and polymorphs of formoterol fumarate.
abstract: The solid-state structures of two polymorphs and two alcoholates (ethanol and isopropanol) of formoterol fumarate have been investigated by a combination of NMR techniques. First-principles shielding computations are combined with NMR data to successfully relate peaks to their crystallographic positions for the solvates, including atoms that are in equivalent molecular positions. The uncharacterised structure of the asolvate form C is found to contain a single formoterol ion and half a fumarate ion in its asymmetric unit. HETCOR experiments for the ethanolate and form C allow proton chemical shifts to be determined and give improved (13)C resolution for the former compound. Desolvation of the solvates to form C has been monitored under the conditions of the NMR experiment. Differential rates of phenylene ring flipping are observed in the different forms. Carbon-13 relaxation times and (2)H NMR are used to probe dynamics of the fumarate ion.
authors.affiliation: Department of Chemistry, Durham University, Durham, UK. d.c.apperley@durham.ac.uk
authors.forename: David C
authors.initials: DC
authors.lastname: Apperley
authors.forename: A Fraser
authors.initials: AF
authors.lastname: Markwell
authors.forename: Robin K
authors.initials: RK
authors.lastname: Harris
authors.forename: Paul
authors.initials: P
authors.lastname: Hodgkinson
mesh_terms: D003460:Crystallization; D018360:Crystallography, X-Ray; D004983:Ethanolamines / Q000737:chemistry*; D000068759:Formoterol Fumarate; D006860:Hydrogen Bonding; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure
chemical_list: D004983:Ethanolamines; D000068759:Formoterol Fumarate