EPR Spectral Determination of Electronic Substituent Effects on the <i>D</i> Values of Hydrocarbon Polyradicals (Quintet and Septet Spin States) Composed of Localized 1,3-Cyclopentanediyl Spin-Carrying Units Linked by 1,3-Di- and 1,3,5-Trimethylenebenzene Ferromagnetic Couplers
作者:Waldemar Adam、Wiebke Maas
DOI:10.1021/jo0012795
日期:2000.11.1
diradicals D-3a,b (triplets), tetraradicals T-3a,b (quintets), and hexaradicals H-3a,b (septets) were photochemically generated in matrix-isolated form (toluene, 77 K) by successive denitrogenation of the trisazoalkanes 3a,b and EPR spectrally characterized. In these high-spin polyradicals the spin-spin interaction within the localized spin-carrying 1,3-cyclopentanediyl diradical unit is much stronger
母体和对硝基苯基取代的双自由基D-3a,b(三重峰),四自由基T-3a,b(五重峰)和六自由基H-3a,b(九重峰)以基质分离的形式(甲苯,77 K)通过三偶氮烷3a,b的连续脱氮和EPR进行光谱表征。在这些高自旋多自由基中,局部自旋携带的1,3-环戊二基二自由基单元中的自旋-自旋相互作用比交叉共轭铁磁耦合单元中的自旋-自旋相互作用强得多。因此,环戊二基单元中电子性质的变化决定性地影响整个多自由基的D值。因此,自旋接受的对硝基基团以与双自由基相同的量减少四和六自由基的D值。因此,无论自旋多重性如何,