10.1021/jo501260c.s002
Meng Chu
Meng
Chu
Ashley N. Scioneaux
Ashley N.
Scioneaux
C. Scott Hartley
C. Scott
Hartley
Solution-Phase Dimerization
of an Oblong Shape-Persistent
Macrocycle
American Chemical Society
2014
compound
fluorescence spectroscopies
dimer geometry
displacement
core measures
triphenylene units
NMR shielding
UV
candidate dimer geometries
1 H NMR signals
Å.
3.6 Å
CDCl 3
alkoxy groups
side chains
DFT calculations
steric interactions
2014-10-03 00:00:00
Dataset
https://acs.figshare.com/articles/dataset/Solution_Phase_Dimerization_of_an_Oblong_Shape_Persistent_Macrocycle/2249461
A new
shape-persistent macrocycle comprising two 2,3-triphenylene
moieties bridged by <i>m</i>-phenylene ethynylenes has been
synthesized. UV–vis and fluorescence spectroscopies indicate
limited interaction between the two triphenylene units. The compound,
which has a pronounced oblong shape (the core measures approximately
2.2 × 1.0 nm), aggregates in CDCl<sub>3</sub> and toluene-<i>d</i><sub>8</sub> to give stacked dimers, as indicated by the <sup>1</sup>H NMR signals corresponding to protons on or near the core,
which shift upfield with increasing concentration. These changes in
NMR shielding were modeled using DFT calculations on candidate dimer
geometries. The best match to the experimental data was obtained for
a dimer consisting of arene–arene stacking by 3.6 Å (on
average) with a displacement along the molecular long axis of 3.5–4.0
Å. This displacement is larger than can be explained by the electronic
effects of aromatic stacking interactions. Instead, the minimization
of steric interactions between the side chains appears to control
the dimer geometry, with the alkoxy groups of one molecule sliding
into registry with the gaps along the periphery of the other. Such
lateral displacement (as opposed to rotation) is a direct consequence
of the extended oval shape of the compound.