Boron-11 NMR spectra of boranes, main-group heteroboranes, and substituted derivatives. Factors influencing chemical shifts of skeletal atoms

Syntheses and catalytic activities of single-wall carbon nanotubes-supported nickel (II) metallacarboranes for olefin polymerization

“…The d 11 B of apical boron in (7) shifts downfield from d K37.50 ppm in its precursor (6) to K24.15 ppm. This is consistent with literature [14]. The 1 H NMR spectrum and analytic data of (7) are consistent with the molecular structure presented in Scheme 1.…”

NMR Spectroscopy, Heteronuclei, B, Al, Ga, In, Tl

“…Hence, the 11 B signal of Et 2 B(benzoinato) [4] at 55 ppm is indicative of a three-coordinate environment at boron with the uncoordinated carbonyl group of the bifunctional benzoinato ligand. For example, the d 11 B values for three-coordinate R 2 BNR 0 R 00 and R 2 BOR 0 compounds are found approximately in the range 44-50 ppm and 50-55 ppm, respectively.…”

“…The structures of dialkylboron derivatives of saturated and unsaturated hydroxy carbonyl compounds, Et 2 B(benzoinato) [4] and Et 2 B(maltolato) [5], are a good illustration of the importance of p-bonding between boron and oxygen. However, the utility of 11 B NMR to determine the Lewis acid strength of three-coordinate boranes is strongly limited, since the magnitude of chemical shift change upon coordination reflects the p-bonding effect in a parent borane as well as the sensitivity to steric factors.…”

“…For example, the 71 Ga chemical shifts for compounds of type GaAlX 4 show a considerable dependence on the type of AlX À 4 anion and deshielding of about 130 ppm was observed: from À680 ppm (AlCl À 4 ) and À635 ppm (AlBr À 4 ) to À552 ppm (AlI À 4 ). For example, the 71 Ga chemical shifts for compounds of type GaAlX 4 show a considerable dependence on the type of AlX À 4 anion and deshielding of about 130 ppm was observed: from À680 ppm (AlCl À 4 ) and À635 ppm (AlBr À 4 ) to À552 ppm (AlI À 4 ).…”

Sorption properties and reversibility of Ti(IV) and Nb(V)-fluoride doped-Ca(BH4)2–MgH2 system

“…boron, CaB 12 H 12 ). [15,16] The addition of transition-metal chlorides and fluorides (TiCl 3 , NbF 5 and TiF 4 ) demonstrated to be beneficial to avoid the formation of boron and drive the decomposition reaction to CaB 6 which was reported to be essential for the occurrence of the reversible reaction. [10,17,18] In fact, when transition-metal chlorides and fluorides are combined with a hydride phase and subjected to the mechanochemical processing, they transforms into more stable compounds (e.g.…”