HALOGEN-SCRAMBLING MECHANISM LEADING TO FORMATION OF MIXED BORON TRIHALIDE ADDUCTS OF TRIMETHYLAMINE
HALOGEN-SCRAMBLING MECHANISM LEADING TO FORMATION OF MIXED BORON TRIHALIDE ADDUCTS OF TRIMETHYLAMINE
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DOI：
10.1139/v74-417
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发表时间：
1974-01-01
期刊：
影响因子：
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通讯作者：
MILLER, JM
中科院分区：
文献类型：
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作者：
BENTON, BW;MILLER, JM
三卤化硼的三甲胺加合物Me 3 N·BX 3在溶液中与游离三卤化硼BY 3反应生成混合卤化物加合物Me 3 N·BX 2 Y。同位素标记显示B-N键保持完整，反应在任一方向进行，即X或Y可能是较重的卤素。一个桥接的过渡态，涉及五配位硼被假定。只有在Me 3 N·BI 3的情况下，B-X键的离子预解离通过与离子物种的反应来表示。两个加合物在溶液中不反应，而不存在过量的刘易斯酸，再次表明缺乏预解离。在气相中，两个加合物甚至在没有过量酸的情况下也会扰乱它们的卤素，但这些反应通过B-N键断裂发生。
Trimethylamine adducts of the boron trihalides, Me3N•BX3are shown to react in solution with free boron trihalides BY3to yield mixed halide adducts such as Me3N•BX2Y. Isotope labelling shows that the B—N bond remains intact and that the reaction proceeds in either direction,i.e. either X or Y may be the heavier halogen. A bridged transition state involving five-coordinate boron is postulated. Only in the case of Me3N•BI3is an ionic predissociation of a B—X bond indicated by reaction with ionic species. Two adducts do not react in solution without the presence of excess Lewis acid, again indicative of a lack of predissociation. In the gas phase two adducts will scramble their halogens even in the absence of excess acid but these reactions occur via B—N bond cleavage.