The iodine - 127 NQR investigation of simple and complex iodates

The solid-state 19F NMR spectrum of [N(CH3)4][IO2F2], a vibrational study of [N(CH3)4][IO3] and [N(CH3)4][IO3]·2H2O, and the X-ray crystal structures of [N(CH3)4][IO2F2] and [N(CH3)4][IO3]

“…The best fit with the experimental trace was obtained for 1 J( 127 I-19 F) = À1000 Hz and R = 0.02. At the current field strength (11.744 T), n( 127 I) = 99.914 MHz, and R = 0.02 corresponds to a quadrupolar coupling constant, x = 5000 MHz, which is of the same order of magnitude as that obtained for the IO 3 À anion (1000 MHz) [34]. The value of 1000 Hz for j 1 J( 127 I-19 F)j is in the expected range when compared with the known and calculated j 1 J( 127 I-19 F)j values for iodine(V) and (VII) fluorides: IF 6 + (2744 Hz) [27], IF 7 (2100 Hz) [28], IF 4 + (F eq : 1572 Hz, F ax : 653 Hz) [37].…”

Correlation between Structural, Infrared and Nuclear Quadrupole Resonance Data of Iodates

“…Nevertheless, the value of eQq is smaller. This could be expected from the common behaviour of eQq decrease while encreasing the cation radius in the series of alkaline metals [9].…”

“…Thus, when going from alkaline metal iodates to metal iodates with higher valencies, the bond covalency between the oxygen and metal increases, and this causes an increase of both the asymmetry parameter and quadrupole coupling constant. A correlation between these values and metal valencies V takes place [9,14]: ri = 0.111« -0.095, eQq (MHz) = 23.24 n + 974.57.…”

“…A weak (< 5%) but regular decrease at the transition from Li to Cs is observed, which demonstrates the decrease of ionic contribution with increasing ionic radius and a decrease of the cation polarizing capabilities. This shows that the EFG is mainly due to covalent iodineoxygen bonds [9,12].…”