55124-38-4Relevant articles and documents
Dialkylaminohydridophenoxyboranes. Convenient preparation and studies of intramolecular boron-nitrogen π bonding
Kovar, Roger A.,Waldvogle, Gene G.
, p. 2239 - 2243 (2008/10/08)
A convenient preparation of dialkylaminohydridophenoxyborane compounds (HBOC6H5NR'2) has been developed according to the following three-step sequence: (1) 4BF3 (etherate) + 3NaBH4 = 3NaBF4 + 2B2H6(g); (2) 1/2B2H6(g) + HNR'2 = H3BNHR'2; (3) H3BHNR'2 + HOC6H5 + heat = 2H2 + HBOC6H5NR'2; HNR'2 = HN(CH3)2, HN(C2H5)2, HN(i-C3H7)2, HN(n-C4H9)2, HN(CH2C6H5)2, HNC4H8, and HNC5H10. The final products are isolated in yields ranging from 70 to 90% by vacuum distillation at moderate temperatures. Molecular association and variable-temperature proton magnetic resonance studies of these compounds in benzene solution are consistent with a planar, monomeric configuration with considerable π interaction between boron and nitrogen and hindered rotation about this bond. The Lewis acid behavior of diisopropylaminohydridophenoxyborane toward ammonia and trimethylamine was determined using a tensimetric titration procedure. No evidence of interaction was observed with trimethylamine while a stable 1:1 adduct was formed in the case of the reaction involving ammonia: HBOC6H5N(i-C3H7)2 + NH3 = HBOC6H5N(i-C3H7)2-NH 3. The room-temperature proton magnetic resonance spectrum of the ammonia adduct of diisopropylaminohydridophenoxyborane has demonstrated relatively unrestricted rotation about the secondary amino nitrogen-boron bond.
