An ESR study of x-irradiated diacetylene single crystals at 77 K

Abstract

Single crystal monomers of the bis(p‐toluene sulfonate) ester of 2,4‐hexadiyne‐1,6‐diol x irradiated at 77 K give rise to an intense ESR spectrum at 77 K consisting of triplets of doublets of doublets. The principal hyperfine tensor components of the triplet equal 19.7, 15.7, and 13.1 G, while the hyperfine tensor components of the doublets are equal to (4.5, 3.2, 2.6 G) and (3.2, 2.5, 2.0 G), respectively. The principal g values are equal to 2.0020, 2.0023, and 2.0029. Based on an INDO calculation the ESR spectrum appears to be due to the radical (oligomer) –C(CH₂OR′) –C=C=C=CH₂OR′. A small concentration of a triplet species was also observed.