英语翻译

英语翻译
Comparison of the stacking periodicity along the columnar
axis and that along the molecular disc normal (h0 and h,
respectively) indicates that the molecules are stacked almost
perpendicular to the columnar axis (see Table S1 in the
Supporting Information).[16] Furthermore,the molecules
likely stack in an alternated fashion in order to fill the
available space between neighbors.This is also indicated by
molecular dynamics (MD) simulations in which a column
model was built from a periodic cylindrical cell with a 13.3-G
height (4 I 3.33 G,corresponding to four stacked molecules),
in keeping with the experimental X-ray data.These calculations
show a good space-filling of the available volume as
well as the enhancement of the microsegregation over the
entire simulation experiment time,contributing to the
cohesion of the columnar structure.Moreover,the model
showed that the cohesion of the columns is further reinforced
by Pt–Pt and Pt–alkyne interactions,as also revealed by the
sharp wide-angle signal (h0).The BF4
\3 anions are located
between the complexes.Snapshots of the MD experiment
account for the excellent molecular packing of 2c in the
hexagonal columnar (Colh) phase as shown in Figure 4.The
size of the central rigid electron-rich core is around 2 nm,a
value that is very close to the smallest width of a fiber as
determined for 2b by TEM in dilute gels.
Finally,the organization of these fibrillar superstructures
on well-defined crystallographic surfaces such as mica and
highly ordered pyrolytic graphite (HOPG) was also investigated
(note that the molecules were deposited on amorphous
carbon films for the TEM investigations).A diluted gel
(0.08 mmolL\31) of 2b was deposited by drop-casting on a
mica substrate.As shown in Figure 5a,fibers with no
apparent orientational order and an average height of 2 nm
(see cross-section of Figure 5b) are clearly visible.
Interestingly,a diluted dodecane gel of compound 2b
deposited by spin-coating on freshly cleaved HOPG leads to
self-assembly of molecular fibers that follow mainly the
preferential crystallographic directions of the underlying
HOPG substrate (Figure 5c).The threefold symmetry of
the segment pattern is particularly visible at intercepts where
the fibers form angles of 608 and 1208 to each other.The crosssections
show the presence of two types of fibers corresponding
to two different molecular heights,namely (2.0\50.1) nm
and (4.0\50.3) nm (Figure 5d).The 2-nm high fibers can be
considered to be made of single molecular layers that lie flat
on the surface (Figure S1 in the Supporting Information).The
4-nm high fibers are made of two such piled up layers,with
their alkyl chains still lying parallel to the surface.