STRUCTURES OF STERICALLY OVERCROWDED AND CHARGE-PERTURBATED MOLECULES, .51. OXIDATIVE DECOMPOSITION OF TETRAISOPROPYLTETRAZENE - ISOLATION AND SINGLE-CRYSTAL STRUCTURES OF THE RADICAL-CATION SALT N=CIRCLE-PLUS-N-N(CH-(CH3)2)2](SBCL6-CIRCLE-MINUS) AND OF THE N2 ELIMINATION PRODUCT 3C)2HC-HN-CIRCLE-PLUS=C(CH3)2](SBCL6-CIRCLE-MINUS)

The single-electron oxidation of tetraisopropyltetrazene by the advant ageous, oxygen-free SbCl2/H2CCl2 redox system yields dark-red crystals of tetraisopropyltetrazenium hexachloroantimonate. Their structure de termination at temperatures of 100, 200, and 293 K, the first one of a 2-tetrazene radical cation, proves a planar skeleton C2N-N=N-NC2(+) w ith nearly identical NN bond lengths. The reaction of tetraisopropylte trazene with surplus SbCl5 yields the N2 elimination product isopropyl isopropylideneammonium hexachloroantimonate, which also has been cryst allized and structurally characterized. Due to the conformation of the C3 subunits perpendicular to each other, the cation (H3C)2HC-HN(+) =C (CH3)2 is extremely overcrowded as demonstrated by an angle CNC of 129 -degrees. In addition, the thermal decomposition of tetraisopropyltetr azene in the gasphase has been analyzed PE-spectroscopically, its firs t and second oxidation potentials have been determined cyclovoltammetr ically, and the ESR signal pattern of its radical cation in solution h as been recorded and assigned. Based on the experimental data, a possi ble pathway for the oxidative decomposition of the title compound is d iscussed.