SIMULTANEOUS AND INDEPENDENT ROTATIONS WITH ARBITRARY FLIP ANGLES ANDPHASES FOR I, IS-ALPHA, AND IS-BETA SPIN SYSTEMS

A new pulse sequence element for simultaneous and independent rotation s with arbitrary flip angles and phases for isolated I, ISalpha, and I Sbeta resonances without the use of selective radiofrequency pulses is introduced and experimentally demonstrated. S is a directly attached heteronucleus either at natural abundance or isotopically enriched. Th is pulse sequence element, dubbed TIG-BIRD (triselective independent g yrations BIRD), generalizes earlier elements like BIRD, TANGO, BANGO, and BIG-BIRD, the latter of which allows for arbitrary selection of hi p angles and phases for I and IS spin systems without discriminating b etween ISalpha and ISbeta resonances. For ISalpha and ISbeta spin syst ems it also generalizes the spin-state-selective excitation ((SE)-E-3) element selectively exciting only one of the ISalpha or ISbeta resona nces. TIG-BIRD is a nonselective addition to the NMR toolkit which eff ects the equivalent of three independent selective rotations for I, IS alpha, and ISbeta resonances. (C) 1998 Academic Press.