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Selective Consecutive Insertion of Alkynes into the B–Se Bonds of 1,3,2‐Diselenaborolane Derivatives: Synthesis and Molecular Structures of Nine‐Membered Rings
Author(s) -
Wrackmeyer Bernd,
Klimkina Elena V.,
Milius Wolfgang
Publication year - 2012
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201200471
Subject(s) - chemistry , intramolecular force , ring (chemistry) , crystallography , nmr spectra database , boron , halide , molecular geometry , stereochemistry , nuclear magnetic resonance spectroscopy , molecule , spectral line , organic chemistry , physics , astronomy
Various alkynes have been inserted selectively and stepwise into the B–Se bond(s) of 1,3,2‐diselenaboracyclopentanes {as the 4,5‐[1,2‐dicarba‐ closo ‐dodecaborano(12)] derivatives}. The B ‐phenyl derivative was much less reactive than the B ‐halogeno derivatives. The proposed structures were confirmed in solution by multinuclear NMR studies ( 1 H, 11 B, 13 C and 77 Se NMR), also supported by DFT calculations of the gas‐phase molecular geometries and NMR parameters [B3LYP/6‐311+G(d,p) level of theory]. Isotope‐induced nuclear shielding 2 Δ 10/11 B( 13 C) across weak intramolecular coordinative Se–B bonding was observed in the 13 C NMR spectra of the nine‐membered‐ring compounds. The molecular structures of two nine‐membered‐ring structures with B–Cl and B–Br functions were determined by X‐ray diffraction. In addition, it was shown that the slow hydrolysis of these boron halides afforded the corresponding diboroxanes and borinic acids, the structures of the former being determined by X‐ray diffraction.