title: r TPPM: towards improving solid-state NMR two-pulse phase-modulation heteronuclear dipolar decoupling sequence by refocusing.
abstract: We present here a simple refocused modification, r TPPM, of the Two-Pulse Phase-Modulation (TPPM) heteronuclear decoupling method, which improves decoupling and makes the sequence much more robust with respect to essential experimental parameters. The modified sequence is compared with the established TPPM sequence and a variety of other decoupling sequences at low to moderate magic-angle spinning frequencies. Simulations are shown to compare TPPM and r TPPM with respect to various experimental parameters. The observations from simulations are corroborated with experimental findings at two spinning frequencies on U-(13)C-glycine and U-(13)C-L-histidine.HCl.H2O.
authors.affiliation: Center for Insoluble Protein Structures (inSPIN), Interdisciplinary Nanoscience, Center (iNANO) and Department of Chemistry, Aarhus University, Gustav Wieds Vej 14, DK-8000 Aarhus C, Denmark.
authors.forename: Asif
authors.initials: A
authors.lastname: Equbal
authors.affiliation: Department of Chemistry, Center for Excellence in Basic Sciences, University of Mumbai and Department of Atomic Energy, Health Centre, University of Mumbai, Vidhyanagari Campus, Mumbai 400098, India.
authors.forename: Subhradip
authors.initials: S
authors.lastname: Paul
authors.affiliation: Department of Chemistry, Guru Nanak Dev University, Amritsar 143005, India.
authors.forename: Venus Singh
authors.initials: VS
authors.lastname: Mithu
authors.affiliation: Center for Insoluble Protein Structures (inSPIN), Interdisciplinary Nanoscience, Center (iNANO) and Department of Chemistry, Aarhus University, Gustav Wieds Vej 14, DK-8000 Aarhus C, Denmark.
authors.forename: Joachim M
authors.initials: JM
authors.lastname: Vinther
authors.affiliation: Center for Insoluble Protein Structures (inSPIN), Interdisciplinary Nanoscience, Center (iNANO) and Department of Chemistry, Aarhus University, Gustav Wieds Vej 14, DK-8000 Aarhus C, Denmark. Electronic address: ncn@inano.au.dk.
authors.forename: Niels Chr
authors.initials: NC
authors.lastname: Nielsen
authors.affiliation: Department of Chemical Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005, India; TIFR Centre for Interdisciplinary Sciences, 21 Brundavan Colony, Narsingi, Hyderabad 500075, India. Electronic address: madhu@tifr.res.in.
authors.forename: P K
authors.initials: PK
authors.lastname: Madhu
mesh_terms: D000465:Algorithms; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted
keywords: -TPPM; Heteronuclear dipolar decoupling; Magic-angle spinning; SPINAL; Solid-state NMR; TPPM; r TPPM