Solvent Effects on the g -Value of Di- t -butyl Nitric Oxide

Abstract

The effects of solvents on the g-value of di-t-butyl nitric oxide (DTBNO) have been examined. Plots of the g-value vs. the hyperfine coupling constant of 14N of DTBNO in various solvents formed two different straight lines, for aprotic solvents and for protic solvents. An analysis of the solvent effects on the g-value has also been attempted. The solvent-dependent shifts of the g-value may be divided into three terms, resulting from the blue-shift of the n–π* transition, from the redistribution of the odd electron, and from the delocalization of the lone-pair orbital on the oxygen atom of DTBNO. The first term is calculated from the observed shift of the n–π* absorption in the visible ray spectrum, while the seond one is evaluated from the solvent shift of the g-value of DTBNO in aprotic solvents, where the delocalization of the lone-pair is excepted to be negligible The last term, the difference between the observed shift in the g-value and the sum of the former two terms, is estimated to be in the range from −4×10−5 to −10×10−5, which corresponds to the from 2% to 5% delocalization of the lone-pair electron.