0309022 - ÚCHP 2009 RIV GB eng J - Journal Article
Blechta, Vratislav - Schraml, Jan
Relative Signs of 29Si-13C Couplings.
[Relativni znaménka 29Si-13C couplingu.]
Magnetic Resonance in Chemistry. Roč. 46, č. 8 (2008), s. 734-738. ISSN 0749-1581. E-ISSN 1097-458X
R&D Projects: GA ČR GA203/06/0738; GA AV ČR IAA400720706
Institutional research plan: CEZ:AV0Z40720504
Keywords : nmr * nj(si,c) * ghmqc-relay
Subject RIV: CF - Physical ; Theoretical Chemistry
Impact factor: 1.443, year: 2008 ; AIS: 0.453, rok: 2008
DOI: https://doi.org/10.1002/mrc.2241

Two pulse sequences applicable to the determination of relative signs of coupling constants, gHSQC RELAY(P) and gHSQC RELAY(D), were developed and tested. These sequences are suitable for determination of relative signs of long-range coupling constants between two heteronuclei of low abundance (such as 29Si and 13C) and are applicable even to cases in which one of the heteronuclei (29Si) does not exhibit coupling with some of the detected protons (1H). The two sequences differ in the manner in which they suppress undesirable homonuclear coherence transfers. Each of the sequences can be combined with an isotope filter for better suppression of the centerlines arising from more abundant, NMR-inactive isotopes. The sequences were tested on ethoxytrimethylsilane and (E)-(buta-1,3-dienyloxy)trimethylsilane, and we conclude that 2J(29Si O 13C) is positive while 3J(29Si O C 13C) is negative in both compounds.

Byly vyvinuty a testovány pulsní sekvence gHSQC-RELAY (P) and gHSQC-RELAY (D). Tyto sekvence jsou vhodné k detekci relativních znamének long-range coupling konstant (<2Hz) mezi dvěma heterojádry o nízkém přirozeném zastoupení (jako je 29Si a 13C), a to i v případě, že některé detekované protony nejsou couplovaáy k 29Si. Sekvence se liší ve způsobu, jak potlažují nežádoucí homojaderné polarizační přenosy. Sekvence byly testovány na ethoxytrimetkylsilanu a na (E)-(buta-1,3-dienyloxy)trimethylsilanu s výsledkem, že 2J(29Si-O-13C) je pozitivní a 3J(29Si-O-C-13C) je negativní v obou případech.
Permanent Link: http://hdl.handle.net/11104/0161283