XI SO. ( 2 0 m L ) was condensed at -190°C into a pressure flask containing l.Og (6.8 mmol) of 1 and I.0g (3.4mmol) of 3. The colorless solution was allowed to warm up in the dark to room temperature and stirred for 18 h. The moderately soluble precipitate that formed was filtered off and the soI\rnt was removed from the filtrate in vacuum. The residue was recrystallized from SO?, affording 1.6 g (79%) of 4 as pale yellow crystals. m.p = I15 'C (decomposition at 125'C).-IR (nujol): v=2175, 700, 575,498,464, and 395 cm-'.-Raman: v=2175,683, 658,498,460,430, and 206 cm '[9] Freshly prepared 2 (1.56 g, 8.7 mmol), which had been dried in a vacuum d t -30°C. was heated rapidly to the melting point (-3°C) and then added under a stream of nitrogen to 3 (1.29 g, 4.3 mmol) in a pressure ilask at -190°C. In the evacuated flask, 20 m L of SOz was condensed and the stirred solution was then slowly warmed in a cold bath ( -50°C') in the dark over 4 h to room temperature. After two hours of stirring. the sparingly soluble solid was filtered off and the solvent removed from the filtrate. Orange crystals of 5 were obtained by recrystallizing the residue from SO?. Yield: 1.9 g (67%). m.p.=92'C (decomposition dl IlO"C)-lR (nujol): v=2165, 705, 692, 685, 465, and 395 cm ~ : v=2165, 678, 506, 438,420, 401, 223, 189, 180, 127, 93, and 78 cm . '.
Raman