Syntheses, characterization and reactivity of Lewis acid-base adducts based on B-N dative bonds
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- 作者：Sudeshna Saha ; Ravi Kumar Kottalanka ; Tarun K. P ; a ; Klaus Harms ; Stefanie Dehnen ; Hari Pada Nayek
- 关键词：Dative bonds ; Boroxine ; Lewis acid&ndash ; base ; 1 ; 2 Boroxine-base adduct ; Hexamethylenetetramine ; X-ray diffraction
- 刊名：Journal of Organometallic Chemistry
- 出版年：2013
- 出版时间：15 November, 2013
- 年：2013
- 卷：745-746
- 期：Complete
- 页码：329-334
- 全文大小：894 K
文摘
Three Lewis acid-base adducts [(PhBO)3¡¤2hmt] (1), [(PhBO)3-hmt-(PhBO)3] (2) and [{(F-Ph)BO}3¡¤hmt] (3) (hmt?=?hexamethylenetetramine) were prepared by the treatment of phenylboronic acid [PhB(OH)2] or 4-fluorophenylboroxine [{(F-Ph)BO}3] with hexamethylenetetramine (hmt) in methanol or acetone. The solid state structures of all the compounds were established by single crystal X-ray diffraction analysis. Crystal structure determination indicates the formation of boroxine ring through ligand-mediated dehydration of arylboronic acids. Triphenylboroxine acts as a bridge between two hmt molecules in 1, whereas hmt plays the role of a bridging ligand between two triphenylboroxine rings in 2. Compound 1 is rare 1:2 adduct of triphenylboroxine and hmt whereas compound 2 and 3 are 1:2 and 1:1 adducts of triphenylboroxine or 4-fluorophenylboroxine and hmt respectively. The lability of the B-N bond in solution was confirmed by NMR spectroscopy as well as by chemical reaction of 1 with [Co(H2O)6](ClO4)2, resulting in the formation of [Co(H2O)6](ClO4)2¡¤(hmt)2¡¤2H2O (4), a boroxine free hydrogen bonded framework structure.