- Complete reductive cleavage of CO facilitated by highly electrophilic borocations
-
The addition of CO to [((R3N)BH2)2(μ-H)][B(C6F5)4] leads to formation of trimethylboroxine ((MeBO)3) and [(R3N)2BH2][B(C6F5
- Curless, Liam D.,Clark, Ewan R.,Cid, Jessica,Del Grosso, Alessandro,Ingleson, Michael J.
-
-
Read Online
- Indirect nuclear spin-spin coupling constants 1J( 17O,11B). First observation and calculation using density functional theory (DFT)
-
Coupling constants 1J(17O,11B) of borates, borane adducts and boranes with boron-oxygen bonds have been calculated on the basis of optimised molecular structures using the B3LYP/6-311+G(d,p) level of theory. This indicates that such coupling constants can be of either sign and that their magnitudes can be rather small. Since both 11B and 17O are quadrupole nuclei, it is therefore difficult to measure representative data. In the cases of trimethoxyborane and tetraethyldiboroxanes, it proved possible to obtain experimental data 1J( 17O,11B) (22 and 18 Hz) by measurement of 17O NMR spectra at high temperature (120 °C and 160 °C) respectively. The magnitude of these coupling constants is in reasonable agreement with calculated data. In the case of the diboroxane, this points towards a bond angle B-O-B more close to 180° than to 140°.
- Wrackmeyer, Bernd,Tok, Oleg L.
-
p. 949 - 955
(2008/09/16)
-
- GEZIELTE SYNTHESEN FUER BOROXAZINE
-
Cyclo-1-oxa-3,5-diaza-2,4,6-triboranes (A) and cyclo-1,3-dioxa-5-aza-2,4,6-triboranes (B) have been prepared by four different methods: (1) from mixtures of hexamethyldisilazanes and hexamethyldisiloxane with CH3BBr2 (A and B); (2) from (CH3)3SiN2 and CH3BBr2 (B); (3) from cyclo-1-oxa-3,5-diaza-2,4,6-trisilanes and CH3BBr2 (A); and (4) from CH3B2 and hexamethyldisiloxane (A).The products and some by-products were characterized by mass and NMR (1H, 11B, 29Si) spectra.Substances which were separated from the by-products were also analysed.
- Oesterle, Rainer,Maringgele, Walter,Meller, Anton
-
p. 281 - 290
(2007/10/02)
-