Short communication: Thermal stability of the diazohydroborate [1‐N2B10H9]−: degradation to [B20H18]2− anion

The thermal stability of the monodiazohydroborate NMe₄[1‐N₂B₁₀H₉] was studied by thermogravimetric analysis. Under two different atmospheres (air and argon), the thermal decomposition starts at a temperature between 140 and 160 °C. The decomposition residue obtained was separated on a silica gel column. ¹¹B NMR, IR and electrospray mass spectroscopy analyses of the different fractions separated showed that the above decomposition produces (NMe₄)₂[B₂₀H₁₈] as major product (90%), along with smaller amounts of residual NMe₄[1‐N₂B₁₀H₉] (5%), (NMe₄)₂[B₁₂H₁₂] and boric acid. Copyright © 2003 John Wiley & Sons, Ltd.     

Preparation and crystal structures of an ionic triple-hydrogen-bridged derivative of 9-BBN hydroborate zirconium(IV)

An ionic dinuclear triple-hydrogen-bridged 9-BBN hydroborate zirconium complex, [K(Et₂O)₄][{(μ-H)₂BC₈H₁₄}₃Zr(μ-H)₃Zr{(μ-H)₂BC₈H₁₄}₃] (1) was formed from the reaction of Zr{(μ-H)₂BC₈H₁₄}₄ with KH and aniline in diethyl ether. The molecular structure of compound 1 was determined by single-crystal X-ray diffraction analysis. Six 9-BBN hydroborate ligands are coordinated to two Zr atoms via two bridging H atoms, and two Zr atoms are connected by three bridging hydrogens in the anion part of this molecule. The distance of Zr?Zr is 3.1025(5) Å. The crystal structure of 1 suggests that agostic interactions between the zirconium metal center and α-C-H of the 9-BBN hydroborate ligand exist in the solid state. The Zr?H distances corresponding to the α-C-H?Zr agostic interactions are 2.579(4) Å and 2.743(4) Å.     

SYNTHESIS AND SOLUTION NMR-STUDIES OF THE TRIS(3,5-DIMETHYLPYRAZOL-1-YL) HYDROBORATOPALLADIUM(II) COMPLEX,Pd{(pz*)3BH}(PPh3)CI

Abstract

The sterically hindered tris(3, 5-dimethylpyrazol-l-yl)hydroborate complex of palladium, Pd{(pz*)₃BH}(PPh₃)Cl (1) has been prepared by the stepwise reaction of (CH₃CN)₂PdCl₂ with K{(pz*)₃BH}, and then PPh₃. The complex 1 has been fully characterized by microanalysis and various spectroscopic methods. A solution NMR study of 1 revealed that two pz* groups of the {(pz*)₃BH} ligand coordinate to palladium in cis positions, while the remaining group is not coordinated. VT NMR experiments have been performed to determine that signal broadening of the phenyl proton resonances in the ¹H-NMR spectrum is likely attributed to restricted rotation of the coordinated PPh₃ within the congested complex on the NMR time scale. Complex 1 was metastable in solution towards reaction with water to decompose into several uncharacterized species, in which a facile hydrolytic cleavage of the B-H bond proceeded as judged by IR and ¹H-NMR spectra of the products. Reaction of 1 with PPh₃ in CDCl₃ exclusively yielded cis-PdCl₂(PPh₃)₂, implicating a chlorine abstraction from the solvent.     

闭式十氢十硼酸盐的制备及其固体电解质应用研究进展

全固态电池是一种具有前景的电化学储能装置,它可以克服传统有机液体电解质电池的多方面不足,包括电解质易泄漏、稳定性低、易燃和能量密度有限等问题。固态电解质是全固态电池的重要组成部分,开发具有高离子电导率和宽电化学稳定性窗口的固体电解质是研制高能量和高功率密度全固态电池的关键问题之一。硼氢化物基固态电解质作为一类新型电解质,因具有高离子电导率、高热稳定性和低密度等优势而受到了广泛关注。其中,闭式十氢十硼酸碱金属盐是代表性材料之一。自1959年B₁₀H₁₀^2-被发现以来,其合成方法、结构与应用开发都得到了广泛研究。近年来其在固态电解质方面的研究证实,M₂B₁₀H₁₀（M=Na、Li等）及其衍生物具有高离子电导率、高热稳定性和化学稳定性、高电位窗口等特性,是一类颇具前景的固态电解质材料。本文主要综述了B₁₀H₁₀^2-合成方法及其在固态电解质方面的应用研究进展,并对今后B₁₀H₁₀^2-作为固态电解质的发展方向提出了展望。