ic4020724_si_002.cif (18.93 kB)
Coordination of Terpyridine to Li+ in Two Different Ionic Liquids
dataset
posted on 2013-11-18, 00:00 authored by Klaus Pokorny, Matthias Schmeisser, Frank Hampel, Achim Zahl, Ralph Puchta, Rudi van EldikOn
the basis of 7Li NMR experiments, the complex-formation
reaction between Li+ and the tridentate N-donor ligand
terpyridine was studied in the ionic liquids [emim][NTf2] and [emim][ClO4] as solvents. For both ionic liquids,
the NMR data implicate the formation of [Li(terpy)2]+. Density functional theory calculations
show that partial coordination of terpyridine involving the coordination
of a solvent anion can be excluded. In contrast to the studies in
solution, X-ray diffraction measurements led to completely different
results. In the case of [emim][NTf2], the polymeric lithium
species [Li(terpy)(NTf2)]n was
found to control the stacking of this complex, whereas crystals grown
from [emim][ClO4] exhibit the discrete dimeric species
[Li(terpy)(ClO4)]2. However, both structures
indicate that each lithium ion is formally coordinated by one terpy
molecule and one solvent anion in the solid state, suggesting that
charge neutralization and π stacking mainly control the crystallization
process.