Complexation of lithium ion by the cryptand 4,7,13-trioxa-1,10-diazabicyclo(8. 5. 5)eicosane (C21C sub 5 ) in a range of solvents. A sup 7 Li nuclear magnetic resonance and potentiometric titration study
- Univ. of Adelaide, South Australia (Australia)
Complexation of Li{sup +} by the cryptand 4,7,13-trioxa-1,10-diazabicyclo(8.5.5)eicosane (C21C{sub 5}) to form the cryptate (Li.C21C{sub 5}){sup +} has been studied in eight solvents by {sup 7}Li NMR and potentiometric titration methods. The variation of the {sup 7}Li chemical shift of (Li.C21C{sub 5}){sup +} with solvent and a comparison of its stability with those of other cryptates indicate that (LiC21C{sub 5}){sup +} exists substantially in the exclusive form in solution in contrast to the inclusive form adopted in the solid state. The exchange of Li{sup +} on (Li.C21C{sub 5}){sup +} is within the {sup 7}Li NMR time scale in methanol, dimethylformamide, diethylformamide, and dimethylacetamide, where, in the last solvent at 298.2 K, the logarithm of the (Li.C21C{sub 5}){sup +} stability constant (log (K/dm{sup 3}mol{sup {minus}1})) is 1.85 and the decomplexation kinetic parameters are k{sub d} = 237 {plus minus} 4 s{sup {minus}1}, {Delta}H{sub 3}{double dagger} = 49.0 {plus minus} 2.1 kJ mol{sup {minus}1}, and {Delta}S{sub d}{double dagger} = {minus}35.0 {plus minus} 2.8 J K{sup {minus}1} mol{sup {minus}1}. Similar data are obtained in the other three solvents. In acetonitrile, propylene carbonate, and acetone, Li{sup +} exchange is too slow to be studied by {sup 7}Li NMR spectroscopy. The (Li.C21C{sub 5}){sup +} data are compared with those for (Li.C211){sup +}, (Na.C21C{sub 5}){sup +}, and (Na.C211){sup +}. 29 refs., 4 figs., 4 tabs.
- OSTI ID:
- 6170489
- Journal Information:
- Inorganic Chemistry; (USA), Journal Name: Inorganic Chemistry; (USA) Vol. 29:18; ISSN 0020-1669; ISSN INOCA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400201* -- Chemical & Physicochemical Properties
400202 -- Isotope Effects
Isotope Exchange
& Isotope Separation
ALKALI METAL ISOTOPES
CARBOXYLIC ACIDS
CHEMICAL PREPARATION
COMPLEXES
DATA
EICOSANOIC ACID
EXPERIMENTAL DATA
INFORMATION
ISOTOPES
LIGHT NUCLEI
LITHIUM 7
LITHIUM COMPLEXES
LITHIUM ISOTOPES
MAGNETIC RESONANCE
MONOCARBOXYLIC ACIDS
NUCLEAR MAGNETIC RESONANCE
NUCLEI
NUMERICAL DATA
ODD-EVEN NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
POTENTIOMETRY
RESONANCE
STABLE ISOTOPES
SYNTHESIS
TITRATION