title: ADEQUATE CR: 13C connectivity mapping in indirect detection mode with composite refocusing.
abstract: We report a novel rare spin correlation experiment termed ADEQUATE with composite refocusing (CR), which is the (1)H-detected version of 2D INADEQUATE CR. ADEQUATE CR begins with a polarization transfer from protons to the attached carbon, followed by (13)C-(13)C double-quantum (DQ) preparation. Unlike the ADEQUATE class of experiments, (13)C DQ coherence is converted after evolution to single-quantum single transitions (SQ-STs) by CR. (13)C SQ-ST is then transferred back to the coupled protons by a coherence order selective reconversion. The present sequence produces partial transition selectivity in the (1)H dimension as does (1)H Indirect detected (13)C Low-Abundance Single-transition correlation Spectroscopy (HICLASS), thereby mitigating the reduction in sensitivity enhancement because of the presence of homonuclear proton couplings. However, unlike HICLASS (which is an experiment that involves SQ-TS evolution), no homonuclear zero quantum mixing is required on the (13)C channel in the present experiment. Experimental results are demonstrated on a variety of samples, establishing the efficiency of the proposed method.
authors.affiliation: MRI-MRS Centre, Department of Chemistry, Indian Institute of Technology - Madras, Chennai, 600036, Tamil Nadu, India.
authors.forename: Christy
authors.initials: C
authors.lastname: George
authors.forename: N
authors.initials: N
authors.lastname: Chandrakumar
mesh_terms: D002247:Carbon Isotopes; D009682:Magnetic Resonance Spectroscopy; D011522:Protons; D012015:Reference Standards
chemical_list: D002247:Carbon Isotopes; D011522:Protons
keywords: 13C; 1H; 1H transition selectivity; 1H-detected INEPT-INADEQUATE; ADEQUATE; ADEQUATE CR; HICLASS; INADEQUATE; NMR; rare spin correlation