Donor–acceptor adducts of the mixed boron trihalides: adducts of dimethyl ether

Abstract

N.m.r. studies of halogen redistribution in dimethyl ether-boron trihalide adducts in solution show that equilibrium between mixed and unmixed-halogen adducts is attained rapidly. Near-statistical amounts of the mixed and unmixed-halogen species are present a t equilibrium in the Me,O,BF,CI,-,(n = 0-3) system. Decomposition is a serious competing reaction in adducts containing boron-bromine and especially boron-iodine bonds. Exchange reactions and trends in the n.m.r. parameters are discussed.THE mixed boron trihalides BX,Y axe unstable to dis-however, well known in mixtures of the corresponding proportionation and have not been isolated. They are, simple halides BX3 and BY,.l-3 Although numerous l A.

Kinetics and mechanism of hydroboration reactions of HBBr2·SMe2 and HBCl2·SMe2 – Application of 11B NMR spectroscopy

“…To this end, infrared (IR) spectroscopy has been employed in kinetic investigations of various organoboranes [5][6][7][8][9][10]17,18]. 11 B NMR spectroscopy has also been shown to be an invaluable qualitative and analytical tool for many studies [19][20][21][22][23][24][25]. Yet, despite all these applications, 11 B NMR spectroscopy has not been exploited in the direct investigation of kinetic and mechanistic aspects of the hydroboration reaction, up until a recent publication by Jaganyi and Mzinyati [26].…”

Mixed Boron Trihalide Adducts. A Nuclear Magnetic Resonance Study of Halogen Redistribution in Adducts of Trimethylphosphine, Trimethylphosphine Oxide, and Trimethylphosphine Sulfide

“…'H spectra revealed no impurities in any of the bases. T h e purification of the boron trihalides and methylene chloride has been described previously (3), as has the n.m.r. instrumentation (1, 3).…”

The Halogen-scrambling Mechanism Leading to Formation of the Mixed Boron Trihalide Adducts of Trimethylamine

“…Trimethylamine and the boron trihalides were purified as described elsewhere (2). The pure unmixed adducts were similarly prepared and purified (17,4).…”