Solution containing a nitroxide radical for magnetometry by nuclear magnetic resonance

摘要

A soln. for magnetometry by nuclear magnetic resonance contains a nitroxide radical of formula (I), where R1-R4 = opt. deuterated alkyl or alkoxy; or R1+R2 and/or R3+R4 = opt. deuterated cycloalkyl or polycycloalkyl; and N = <14>N or <15>N. (I) is dissolved in a solvent comprising a mixt. of water and cpd(s). chosen such that the soln. contains an oxidising agent of the reduced form of (I) and has viscosity suitable for magnetometry at 20-200 degrees C. Also claimed is an NMR spectrometer without forbidden axes which includes 2 units each composed of a coil surrounding a sample of a soln. contg. (I) and 2 resonant cavities to excite the samples at 2 distinct frequencies.