Fernández Ignacio, Martínez-Viviente Eloísa, Pregosin Paul S
Laboratory of Inorganic Chemistry, ETHZ HCI Hönggerberg CH-8093 Zurich, Switzerland.
Inorg Chem. 2005 Jul 25;44(15):5509-13. doi: 10.1021/ic050523d.
(1)H, (19)F, and (7)Li pulsed gradient spin-echo (PGSE) NMR measurements for a series of salts are reported. The (7)Li is shown to complement the (1)H and (19)F measurements; however, the use of higher concentrations (for the less-sensitive (7)Li) can lead to aggregation. For all of the salts discussed {Li(BF(4)); (n-Bu(4)N)(BF(4)), a trinuclear Ru cluster; Ir(1,5-COD)(4), where 4 is a chiral P,N ligand; and the crown ether stabilized potassium salt, [K(18-crown-6)(NPh(2))], 6}, the use of THF seems to promote strong ion pairing. In several cases, the degree of ion pairing approaches 100%. In THF solution, the potassium salt, 6, prefers to exist as a more classical ion pair rather than as the pi complex found in the solid state. In some cases, (1)H, (1)H NOESY and (1)H, (19)F HOESY spectra help to pinpoint the cation/anion spatial relationship.
报道了一系列盐的（1）H、（19）F和（7）Li脉冲梯度自旋回波（PGSE）核磁共振测量结果。结果表明，（7）Li可补充（1）H和（19）F测量；然而，使用较高浓度（针对灵敏度较低的（7）Li）会导致聚集。对于所讨论的所有盐{Li（BF₄）；（n-Bu₄N）（BF₄），一种三核Ru簇；[Ir（1,5-COD）₄]（BF₄），其中4是一种手性P，N配体；以及冠醚稳定的钾盐，[K（18-冠-6）（NPh₂）]，6}，使用四氢呋喃（THF）似乎会促进强离子对的形成。在几种情况下，离子对程度接近100%。在THF溶液中，钾盐6更倾向于以更典型的离子对形式存在，而不是以固态中发现的π配合物形式存在。在某些情况下，（1）H、（1）H NOESY和（1）H、（19）F HOESY光谱有助于确定阳离子/阴离子的空间关系。
