Synthesis of dendritic, non-kekulé-, and nondisjoint-type triphenylmethanes terminated with galvinoxyl radicals

A series of triphenylmethanes terminated with (a) hydrogalvinoxyl(s), bis(4-tert-butylphenyl)-(4-hydrogalvinoxylphenyl)methoxymethane lad, tris(4-hydrogalvinoxylphenyl)methoxymethane 2ad, and tris{4-[bis(4- hydrogalvinoxylphenyl)methoxymethyl]phenyl}methoxymethane 3ad, were prepared and oxidized to the corresponding galvinoxyl radicals, 1af, 2af, and 3af, which have one, three, and six galvinoxyl radical(s), respectively. Chemical reduction of the galvinoxyl radicals with a Na/K alloy gave stable intermediates, i.e., the tetraanion, decaanion, and docosaanion. The tetraanion was oxidized with an equimolar amount of iodine at ca. 170 K to the galvinoxyl radical-combined triphenylmethyl radical 1cf. The ESR signal of the biradical at room temperature indicated an exchange interaction between the two radicals. The spectrum at 140 K had a zero-field splitting and ΔM_s= ±2 transition signal at half-field, which are characteristic of a multiplet species.