3244-41-5Relevant articles and documents
Reductive coupling of six carbon monoxides by a ditantalum hydride complex
Watanabe, Takahito,Ishida, Yutaka,Matsuo, Tsukasa,Kawaguchi, Hiroyuki
, p. 3474 - 3475 (2009)
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A solid-state NMR and computational study of sodium and potassium tetraphenylborates:23Na and39K NMR signatures for systems containing cation-π interactions
Wong, Alan,Whitehead, Robert D.,Gan, Zhehong,Wu, Gang
, p. 10551 - 10559 (2004)
Sodium and potassium tetraphenylborates were examined by solid-state 23Na and 39K NMR spectroscopy. Analyses of solid-state NMR spectra obtained at 4.70, 11.75, and 19.60 T yielded the following 23Na and 39K NMR parameters: Na[BPh4], |C Q| = 1.24 ± 0.05 MHz, ηQ = 0.0 ± 0.1, δiso = -45.6 ± 0.5 ppm, and Ω = 14 ± 2 ppm; K[BPh4], |CQ| = 1.32 ± 0.05 MHz, ηQ = 0.0 ± 0.1, and δiso = -92 ± 1 ppm. In both Na[BPh4] and K[BPh4], the electric field gradient and chemical shift tensors at the metal site are axially symmetric, in agreement with the crystallographic symmetry. Extensive quantum mechanical calculations were performed for Na[BPh4] and K[BPh4] as well as for a large number of model cation-π systems containing Na+ and K + ions and common aromatic compounds. Experimental and theoretical studies confirm that a highly shielded environment at the metal cation site is a characteristic feature for cation-π interactions, making it useful as a NMR signature for identifying cation-π interactions in proteins and nucleic acids. In this study, powder X-ray diffraction spectra for Na[BPh4] and K[BPh4] were also reported.
Highly nucleophilic dipropanolamine chelated boron reagents for aryl-transmetallation to iron complexes
Dunsford, Jay J.,Clark, Ewan R.,Ingleson, Michael J.
supporting information, p. 20577 - 20583 (2015/12/04)
New aryl- and heteroarylboronate esters chelated by dipropanolamine are synthesised directly from boronic acids. The corresponding anionic borates are readily accessible by deprotonation and demonstrate an increase in hydrocarbyl nucleophilicity in comparison to other common borates. The new borates proved competent for magnesium or zinc additive-free, direct boron-to-iron hydrocarbyl transmetallations with well-defined iron(ii) (pre)catalysts. The application of the new borate reagents in representative Csp2-Csp3 cross-coupling led to almost exclusive homocoupling unless coupling is performed in the presence of a zinc additive.
