Synthesen und Strukturen von 1,3,5-Trihalogeno-1,3,5-triboracyclohexan-Derivaten / Syntheses and Structures of 1,3,5-Trihalogeno-1,3,5-triboracyclohexane Derivatives

Abstract

On heating bis(diiodoboryl)methane (1c) and 1,1-bis(diiodoboryl)alkanes 1i, l (alkane = propane, butane) under reduced pressure elimination of BI3 takes place and the corresponding 1,3,5-triiodo- 1,3,5-triboracyclohexane derivatives 2c; 2i, i’; 2l, l’ are formed. Starting with bis(dichloroboryl)- and bis(dibromoboryl)methane (1a, 1b) only small amounts of the trimerization products (H2C-BCl)3 (2a) and (H2C-BBr)3 (2b) are detectable which can not be separated from 1a,b and by-products. Reaction of 1,3,5-trichloro-2,4,6-trimethyl-1,3,5-triboracyclohexane (2d) with BBr3 provides the corresponding bromo derivative 2e in high yield. An attempt to react 2,4-bis(dichloroboryl)-3-chloro- 3-borapentane (4d) with 1,1-bis(trimethylstannyl)-2,2-diphenylethene does not lead to the expected trichloro-triboracyclohexane, but the divinylchloroborane ClB(CH=CPh2)2 6a, is formed. The compositions of the products follow from analytical data and X-ray structure analyses of 2i, 2c, 2e, and 6a.

A study of M–X–BR3 (M = Pt, Pd or Rh; X = Cl or I) interactions in square planar ambiphilic ligand complexes: structural, spectroscopic, electrochemical and computational comparisons with borane-free analogues

“…Structurally characterized iodoborates (BR 3 I − ) are not available for comparison, but this distance is approximately 0.5 Å longer than the B-I bond in crystallographically characterized iodoboranes (cf. 2.15-2.17 Å in 1,3,5-triiodo-1,3,5-triborocyclohexane, 21 and 2.22-2.25 Å in Me 3 PBI 3 ). 22 The boron atom in 4B is also pyramidalized to a much lesser extent…”

1,1-Carboboration to tellurium–boron intramolecular frustrated Lewis pairs

“…The C(3)-C(4) bond distance of 1.326(4) Å is significantly longer than the typical C-C triple bond and closer to a C-C double bond, thus demonstrating the activation of the C-C triple bond by compound 2. 40 The B-I(2) bond length is also much shorter than the B-I bond length reported for an analogous Pt-I-B bridging complex (2.75(2) Å). Nonetheless, in contrast to other FLPs, 25,31 2 does not react with the internal alkyne such as 1,1-diphenylacetylene, nor does it activate H 2 or bind CO 2.…”

“…0.2 Å longer than B-I single bond distances seen in crystallographically character-ized iodoborate adducts Me 3 P-BI 3 , 39 (2.24-2.27 Å) and 1,3,5triiodo-1,3,5-triborocyclohexane (2.14-2.16 Å). 40 The B-I(2) bond length is also much shorter than the B-I bond length reported for an analogous Pt-I-B bridging complex (2.75(2) Å). 41 The B-I interaction is further evidenced by the pyramidalized B center (∑(C-B-C) = 346.4(3)°) and the fact that the bridging Te-I(2) bond length of 3.0499(4) Å is much longer than the terminal Te-I(1) bond length of 2.7798(4) Å.…”