From Metal Hydrides to Metal Borohydrides

Abstract

Commencing from metal hydrides, versatile synthesis, purification, and desolvation approaches are presented for a wide range of metal borohydrides and their solvates. An optimized and generalized synthesis method is provided for 11 different metal borohydrides, M(BH) , (M = Li, Na, Mg, Ca, Sr, Ba, Y, Nd, Sm, Gd, Yb), providing controlled access to more than 15 different polymorphs and in excess of 20 metal borohydride solvate complexes. Commercially unavailable metal hydrides (MH, M = Sr, Ba, Y, Nd, Sm, Gd, Yb) are synthesized utilizing high pressure hydrogenation. For synthesis of metal borohydrides, all hydrides are mechanochemically activated prior to reaction with dimethylsulfide borane. A purification process is devised, alongside a complementary desolvation process for solvate complexes, yielding high purity products. An array of polymorphically pure metal borohydrides are synthesized in this manner, supporting the general applicability of this method. Additionally, new metal borohydrides, α-, α'- β-, γ-Yb(BH), α-Nd(BH) and new solvates Sr(BH)·1THF, Sm(BH)·1THF, Yb(BH)· xTHF, x = 1 or 2, Nd(BH)·1MeS, Nd(BH)·1.5THF, Sm(BH)·1.5THF and Yb(BH)· xMeS (" x" = unspecified), are presented here. Synthesis conditions are optimized individually for each metal, providing insight into reactivity and mechanistic concerns. The reaction follows a nucleophilic addition/hydride-transfer mechanism. Therefore, the reaction is most efficient for ionic and polar-covalent metal hydrides. The presented synthetic approaches are widely applicable, as demonstrated by permitting facile access to a large number of materials and by performing a scale-up synthesis of LiBH.

Current Understanding of Nonaqueous Electrolytes for Calcium‐Based Batteries

“…7c), which may aide in dissolution. [65] ) CV measurements by Shyamsunder et al with 0.5 M Ca(B(Ohfip)4)2/DME (Au working electrode, 25 mV/s, Fig. 8a) exhibited high peak current densities (-20 mA/cm 2 ), roughly double that of Ca(BH4)2/THF at the same scan rate and similar cutoff voltage, and a CE of 92% (4 th cycle), which increased with cycling.…”

Rapid and One‐Step Transformation of LiAlH4 to Inorganic and Organic Anion Intercalated Li‐Al Layered Double Hydroxides

“…The fact that an ordered layered double hydroxide emerged from LiAlH 4 suggests the possibility of structural similarity between them. Further, recently discovered hydrides containing rare‐earths may become potential precursor to generate layered rare‐earth hydroxides …”

Interplay of NH4+ and BH4− reorientational dynamics in NH4BHAndersson1, Grinderslev2, Jensen3 et al. 2020Phys. Rev. MaterialsSelf Cite111100View full textAdd to dashboardCite

“…A 11 B-enriched sample of NH 4 BH 4 was prepared following previously published procedures [3,13]. Initially, Na 11 BH 4 was synthesized from NaH (Dry, 95%, Sigma Aldrich) [14] and S(CH 3 ) 2 11 BH 3 (10 M, Katchem).…”