136745-52-3Relevant academic research and scientific papers
Synthesis, properties, and ring-ring transformation reactions of cyclic siloxanes incorporating skeletal boron atoms: X-ray crystal structures of the strained boracyclotrisiloxane (PhBO)(Ph2SiO)2 and the boracyclotetrasiloxane (PhBO)(Ph2SiO)3
Foucher, Daniel A.,Lough, Alan J.,Manners, Ian
, p. 3034 - 3043 (2008/10/08)
The cyclic boratrisiloxanes (PhBO)(RR′SiO)2 (1, R = R′ = Me; 2, R = Me, R′ = Ph; 3, R = R′ = Ph) have been prepared via the reaction of the dichlorodisiloxanes 1,3-ClRR′SiOSiRR′Cl with phenylboric acid in the presence of NEt3 as an HCl acceptor. Similar procedures using the appropriate α,ω-dichlorosiloxanes ClMe2Si(OSiMe2)nOSiMe2Cl (n = 1 or 2) afforded the boracyclotetrasiloxane (PhBO)(Me2SiO)3 (4) and the boracyclopentasiloxane (PhBO)(Me2SiO)4 (5). The boracyclotetrasiloxane (PhBO)(Ph2SiO)3 (8) was isolated in low yield from the reaction of 2:1 excess of 1,3-ClPh2SiOSiPh2Cl with PhB(OH)2 in the presence of NEt3. The cyclic borasiloxanes 1 and 3 undergo extensive ring-ring transformation reactions when heated at elevated temperatures in the presence of small quantities of K[OSiMe3]. Similar reactions were detected in solution in the presence of acid or base catalysts. The products of these reactions mainly consist of larger rings containing a single boron atom, together with cyclic and polymeric siloxanes and the boroxin [PhBO]3. Similar, but slower, ring-ring redistribution reactions were detected for the boracyclotetrasiloxane 4. These results are consistent with the presence of additional strain in borasiloxanes containing a six-membered ring. This analysis was supported by a comparison of X-ray structural data obtained for 3 with that for 8. Thus, the boracyclotrisiloxane 3 was found to possess a highly strained six-membered ring with considerable bond angle distortion whereas the nonplanar eight-membered ring present in 8 is appreciably less strained. Crystals of 3 are monoclinic, space group C2/c, with a = 15.703 (6) A?, b = 10.864 (3) A?, c = 17.733 (4) A?, β = 119.14 (2)°, V = 2641 (14) A?3, and Z = 4. Crystals of 8 are monoclinic, space group P21/n, with a = 14.692 (2) A?, b = 13.707 (2) A?, c = 19.932 (3) A?, β = 111.38 (0)°, V = 3737.7 (9) A?3, and Z = 4.
Synthesis and structural characterization of cycloborasiloxanes: the X-ray crystal structures of cyclo-1,3,3,5,5-pentaphenyl-1-bora-3,5-disiloxane and cyclo-1,3,3,5,7,7-hexaphenyl-1,5-dibora-3,7-disiloxane
Brisdon, Brian J.,Mahon, Mary F.,Molloy, Kieran C.,Schofield, Paul J.
, p. 11 - 22 (2007/10/02)
Cycloborasiloxanes 2 (1) and RB containing eight- and six-membered rings, respectively, have been synthesized by the reaction of RB(OH)2 with 1,1,3,3-tetraphenyl-1-3-dihydroxy-1,3-disiloxane or diphe
Triphenylsiloxy and Diphenylsiladioxy Derivatives of Boron
Bhardwaj, P. N.,Srivastava, G.
, p. 300 - 304 (2007/10/02)
Tris(triphenylsiloxy)borane, phenyl bis(triphenylsiloxy)borane, 2-triphenylsiloxy-1,3,2-dioxa-borolanes, -borinanes, -borole and -borin and diphenyl bis(1,3,3,2-dioxa-borolane-2-oxy)silanes have been synthesized by various routes and the reactivity of Si-O-B linkage has been compared with that of Ge-O-B and Sn-O-B linkages.Tris(triphenylsiloxy)-borane reacts with acetyic acid by cleavage of Si-O bond to give triphenylsilyl acetate and boric acid. 2-Triphenylsiloxy-1,3,2-benzodioxaborole forms 1:1 addition complexes with pyridine, triethylamine and aniline.Condensation of diphenylsilane diol with boric acid, tri(isopropoxy)borane or phenyldihydroxyborane yields cyclic derivatives.
