EPR line shapes in fluid solution and electron spin relaxation times and lineshapes in frozen solution were measured at X-band for two dinitroxides. For dinitroxide 1, which has two proxyl nitroxides connected by an amide linkage, the fluid solution spectra are in the strong exchange limit (J >> nitrogen hyperfine coupling) and the interspin distance in glassy water:glycerol is about 8.8 Å. For dinitroxide 2, which has two proxyl nitroxides connected by a bridging ethylenediamine and two amide linkages, the fluid solution spectra are characteristic of dynamic exchange between conformations with strong exchange (J > 850 MHz) and conformations with weaker exchange interaction. For 2, the interspin distance in glassy water:glycerol is about 9.2 Å and J > 600 MHz. T₁ and T_m for both dinitroxides in 1:1 water:glycerol were measured at 10 to 160 K. Relaxation times are within experimental uncertainty of values for a pyrrolinoxyl monoradical and very similar to values for a nitroxide with a piperidinyl ring. These data demonstrate that even for these relatively flexible linkages dipolar interaction with an interspin distance of about 9 Å does not provide an effective spin–lattice relaxation mechanism for dinitroxides in glassy water:glycerol.

流体溶液中的 EPR 线形和电子自旋弛豫时间和冷冻溶液中的线形在 X 波段测量了两种二氮氧化物。对于二硝基氧化物1，它具有通过酰胺键连接的两个代理氮氧化物，流体溶液光谱处于强交换极限（J  >> 氮超精细耦合），玻璃水：甘油中的自旋距离约为 8.8 Å。对于二硝基氧化物2，它具有通过桥接乙二胺和两个酰胺键连接的两个代理氮氧化物，流体溶液光谱是具有强交换 ( J  > 850 MHz) 的构象和具有较弱交换相互作用的构象之间的动态交换的特征。对于2，玻璃水：甘油中的自旋距离约为 9.2 Å 且J  > 600 MHz。两种二硝基氧化物在 1:1 水:甘油中的T ₁和T _m在 10 到 160 K 下测量。弛豫时间在吡咯烷氧基单价基值的实验不确定度范围内，与具有哌啶环的硝基氧的值非常相似。这些数据表明，即使对于这些相对灵活的连接，自旋间距约为 9 Å 的偶极相互作用也不能为玻璃水：甘油中的二硝基氧化物提供有效的自旋-晶格弛豫机制。