title: A toolbox of HSQC experiments for small molecules at high 13C-enrichment. Artifact-free, fully 13C-homodecoupled and JCC-encoding pulse sequences.
abstract: A set of modified HSQC experiments designed for the study of (13)C-enriched small molecules is introduced. It includes an improved sensitivity-enhanced HSQC experiment eliminating signal artifacts because of high-order (13)C magnetization terms generated at high (13)C enrichment. A broadband homonuclear (13)C decoupling sequence based on Zangger and Sterk's method simplifies the complex (13)C-(13)C multiplet structure in the F1 dimension of HSQC. When recording spectra at high resolution, the combination with a multiple-site modulation of the selective pulse outperforms the constant-time HSQC in terms of sensitivity and reliability. Finally, two pulse sequences reintroducing selected J(CC) couplings with selective pulses facilitate their assignments and measurements either in the splitting of the resulting doublets or by modulation of the signal amplitude. A sample of uniformly 92% (13)C-enriched cholesterol is used as an example.
authors.affiliation: Department of Organic Chemistry, University of Geneva, 30 Quai E. Ansermet, 1211, Geneva 4, Switzerland.
authors.forename: Mohammadali
authors.initials: M
authors.lastname: Foroozandeh
authors.forename: Patrick
authors.initials: P
authors.lastname: Giraudeau
authors.forename: Damien
authors.initials: D
authors.lastname: Jeannerat
mesh_terms: D002247:Carbon Isotopes; D002784:Cholesterol / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy / Q000592:standards; D015394:Molecular Structure; D012015:Reference Standards
chemical_list: D002247:Carbon Isotopes; D002784:Cholesterol
keywords: 13C; 13C-enrichment; 1H; HSQC; NMR; broadband homonuclear decoupling; carbon-carbon coupling; spatial encoding