μ-(η-Biphenyl)-bis[(η-benzene)chromium(0)], the Arenechromium Analog of Biferrocene

✍ Scribed by Prof. Dr. Christoph Elschenbroich; Jürgen Heck

• Publisher: John Wiley and Sons
• Year: 1977
• Tongue: English
• Weight: 254 KB
• Volume: 16
• Category: Article
• ISSN: 0044-8249
• DOI: 10.1002/anie.197704791

✦ Synopsis

dine 4-oxide (2f): (3.f) (2.9g, 10mmol) is heated to 160 to 170°C for 5 h in a slow current of N2. B(CH3)3 (0.5 g, 90 %) ) condenses in a cold trap at -78°C. Only (2f) can be detected in the residue by NMR spectroscopy. Distillation at 65 "C/0.3 torr afforded (2 f) (1.8 g, 78 %) as a colorless liquid which forms needle-like crystals (m.p. 53 to 55°C).

1,3-Di-tert-butyl-2,4-dimethyl-l,3,2,4-diazadiboretidine ( 6 u ) : CH3BBr2 (4.1 ml, 43mmol) in CH2CI2 (10ml) is slowly added dropwise to a stirred solution of (5) (9.5g, 22mmol) in CH2Clz (1 5 ml) at -65 "C. The reaction mixture is warmed up and heated under reflux for 2 h ; all volatiles are then removed in cacuo and the residue fractionated by sublimation. (CH3)2SnBr2 (12g, 90%) sublimed at 30 to 65°C (oil-bath temperature)jlO-' torr, and ( 6 a ) (2.5g, 67 %) between 80 and 100"C/lO~z torr. The colorless crystals of ( 6 a ) ate freed from traces of (CH3)2SnBr2 by resubliming twice.