Measurement of interfluorine distances in solids.
(19)F homonuclear dipolar recoupling methods were used to measure internuclear distances ranging from 5 to 12 A in fluorinated organic compounds in the solid state. Magic-angle-spinning-based high-resolution techniques were utilized. Trifluoromethyl and aromatic fluorine groups were separated by rigid aromatic spacers; these compounds were diluted into nonfluorinated host molecule matrices to give isolated homonuclear spin pairs with known internuclear distances. Radiofrequency-driven recoupling (RFDR) was used to elicit magnetization exchange between the spin pairs in 1D and 2D experiments. Simulation of the exchange was accomplished using a Monte Carlo-type algorithm to search the parameter space. These methods allow the determination of distances with an accuracy of 1 A at shorter distances and 2 A at longer distances, with the assumption of no prior knowledge of T(2)(ZQ).
Gilchrist
M L
ML
Department of Chemistry, Columbia University, New York, New York 10027, USA.
Monde
K
K
Tomita
Y
Y
Iwashita
T
T
Nakanishi
K
K
McDermott
A E
AE
D005461:Fluorine / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008433:Mathematics; D055585:Physical Phenomena; D010825:Physics
D005461:Fluorine