ISSN:
0268-2605
Keywords:
boranes
;
pentaborane
;
hexaborane
;
stannylboranes
;
119Sn NMR spectroscopy
;
Chemistry
;
Industrial Chemistry and Chemical Engineering
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
This article briefly reviews this area, describes some of our own recent work and also presents some new data. The preparation and characterization of a series of triphenyltin-substituted penta- and hexaboranes is described. The species 1-(SnPh3)B5H8 (1) and 2,3-μ-(SnPh3)B5H8 (3) are prepared from SnPh3Cl and K[B5H8] by careful selection of solvent and conditions, and the intermediacy of 2-(SnPh3)B5H8 (2), in the formation of 1 from 3, was demonstrated by NMR spectroscopy. The species 1, 2 and 3 were characterized by 11B, 1H and 119Sn NMR spectra and 11B-119Sn coupling was observed for the first time in a polyhedral borane. Crystal structures were determined for 3 and the chloro-derivative of 1, 1-(SnClPh2)B5H8 (4). Using similar techniques, three of the six possible linkage isomers of SnPh2(B5H8)2 namely μ,μ-SnPh2(B5H8)2 (10), μ,2-SnPh2(B5H8)2 (11) and μ,1-SnPh2(B5H8)2 (12) were isolated and completely characterized including crystal structure determinations. The use of non-basic solvents such as CH2Cl2 allows the isolation of the bridging species 3 and 10 whereas basic solvents such as Et2O or THF catalyse the rearrangement to species with the substituent in the 1-position, namely the 1 and 12 isomers. Isomer 11 is prepared by carrying out reactions in EtO2 and 12 is also prepared by the reaction between 4 and K[B5H8] in CH2Cl2. The hexaborane derivatives 2,3-μ-(SnPh3)B6H9, 2,3-μ-(SnMe3)B6H9 and 2,3-μ-(SiPh3)B6H9 were also prepared and characterized although all three species were too unstable to afford crystals suitable for X-ray analysis. Finally, attempts to prepare pentaboranyl derivatives containing two SnPh3 substituents provided evidence for the formation of μ,1-(SnPh3)2B5H7 and 1,2-(SnPh3)2B5H7.
Additional Material:
17 Ill.
Type of Medium:
Electronic Resource
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