hr Sodium Aminodiboranates Na(H3BNR2BH3): Structural and Spectroscopic Studies of Steric and Electronic Substituent Effects

We describe the syntheses of a series of sodium aminodiboranate salts, Na(H3B-NR2-BH3), with different substituents on nitrogen, including sodium salts of the unsubstituted aminodiboranate, H3B-NH2-BH3 -, and of the N-substituted anions H3B-NRR '-BH3 -, where NRR ' = NHMe, NHEt, NH(SiMe3), NEt2, N(i-Pr)2, N(SiMe3)2, NMe(i-Pr), NMe(t-Bu), NMe(SiMe3), and the pyrrolidide and piperidide derivatives NC4H8, NC5H10, and NC5H8-cis-2,6-Me2. The compounds have been characterized by 1H and 11B NMR spectroscopy and IR spectroscopy; crystallographic studies have been carried out for the unsolvated N,N-dimethylaminodiboranate salt Na(H3B-NMe2-BH3) and several sodium aminodiboranate salts in which the sodium ions are solvated with ethers (dioxane, diglyme, tetrahydrofuran, and 12-crown-4) or amines (N,N,N ',N '- tetramethylethylenediamine). One of the structures contains a rare example of an ether ligand in which one oxygen atom bridges between two metal ions. General structural and spectroscopic trends as a function of the substituents on nitrogen are discussed.

Automated summary

This article describes the syntheses of a series of sodium aminodiboranate salts with different substituents on nitrogen. The compounds were characterized by NMR spectroscopy, IR spectroscopy, and crystallographic studies. The presence of rare ether ligands bridging between two metal ions was observed in one of the structures. The study discusses the structural and spectroscopic trends as a function of the nitrogen substituents.