Hydrogen--deuterium exchange between MBH/sub 4/ and MBD/sub 4/ (M = Li, Na). Isotope effects on the /sup 1/H and /sup 11/B NMR spectra of the BH/sub n/D/sub 4-n/ anions and a discussion of exchange reactions in some covalent tetrahydroborate systems

摘要: The H NMR spectra of lithium and sodium borohydrides, in various solvents, have been recorded. resulting chemical shift coupling constant data do not yield any clear indications variations solution structure. Hydrogen-deuterium exchange between LiBH LiBD occurs some ethereal solvents yielding a mixture partially substituted species, LiBHD (n = 0 to 4). These observations are relevant the isotopic distribution products reactions involving covalent borohydrides. Isotope effects B (THF solvent) NaBHD (alkaline aqueous described. Chemical shifts (B H) constants, J(B-H), decrease approximately monatonically with deuterium substitution. isotope considered arise from modification vibrational characteristics (BHD) species.