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
The /sup 1/H NMR spectra of lithium and sodium borohydrides, in various solvents, have been recorded. The resulting chemical shift and coupling constant data do not yield any clear indications of variations in solution structure. Hydrogen--deuterium exchange between LiBH/sub 4/ and LiBD/sub 4/ occurs in some ethereal solvents yielding a mixture of partially substituted species, LiBH/sub n/D/sub 4-n/(n = 0 to 4). These observations are relevant to the isotopic distribution in the products of exchange reactions involving some covalent borohydrides. Isotope effects in the /sup 1/H and /sup 11/B NMR spectra of LiBH/sub n/D/sub 4-n/ (THF solvent) and NaBH/sub n/D/sub 4-n/ (alkaline aqueous solvent) are described. Chemical shifts (/sup 11/B and /sup 1/H) and coupling constants, J(/sup 11/B--H), decrease approximately monotonically with deuterium substitution. These isotope effects are considered to arise from the modification of the vibrational characteristics of the (BH/sub n/D/sub 4-n/)/sup -/ species.
- Research Organization:
- La Trobe Univ., Bundoora, Australia
- OSTI ID:
- 7278548
- Journal Information:
- Inorg. Chem.; (United States), Vol. 16:8
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
DEUTERIUM
ISOTOPE EFFECTS
ISOTOPIC EXCHANGE
BOROHYDRIDES
CHEMICAL SHIFT
COUPLING CONSTANTS
LITHIUM COMPOUNDS
NUCLEAR MAGNETIC RESONANCE
SODIUM COMPOUNDS
ALKALI METAL COMPOUNDS
BORON COMPOUNDS
HYDROGEN COMPOUNDS
HYDROGEN ISOTOPES
ISOTOPES
LIGHT NUCLEI
MAGNETIC RESONANCE
NUCLEI
ODD-ODD NUCLEI
RESONANCE
STABLE ISOTOPES
400202* - Isotope Effects
Isotope Exchange
& Isotope Separation
400203 - Isotope Exchange & Isotope Separation- (-1987)