<s>
In	O
chemistry	O
,	O
a	O
rotaxane	B-Algorithm
(	O
)	O
is	O
a	O
mechanically	O
interlocked	O
molecular	O
architecture	O
consisting	O
of	O
a	O
dumbbell-shaped	O
molecule	O
which	O
is	O
threaded	O
through	O
a	O
macrocycle	O
(	O
see	O
graphical	O
representation	O
)	O
.	O
</s>
<s>
The	O
two	O
components	O
of	O
a	O
rotaxane	B-Algorithm
are	O
kinetically	O
trapped	O
since	O
the	O
ends	O
of	O
the	O
dumbbell	O
(	O
often	O
called	O
stoppers	O
)	O
are	O
larger	O
than	O
the	O
internal	O
diameter	O
of	O
the	O
ring	O
and	O
prevent	O
dissociation	O
(	O
unthreading	O
)	O
of	O
the	O
components	O
since	O
this	O
would	O
require	O
significant	O
distortion	O
of	O
the	O
covalent	O
bonds	O
.	O
</s>
<s>
Much	O
of	O
the	O
research	O
concerning	O
rotaxanes	B-Algorithm
and	O
other	O
mechanically	O
interlocked	O
molecular	O
architectures	O
,	O
such	O
as	O
catenanes	O
,	O
has	O
been	O
focused	O
on	O
their	O
efficient	O
synthesis	O
or	O
their	O
utilization	O
as	O
artificial	O
molecular	O
machines	O
.	O
</s>
<s>
However	O
,	O
examples	O
of	O
rotaxane	B-Algorithm
substructure	O
have	O
been	O
found	O
in	O
naturally	O
occurring	O
peptides	O
,	O
including	O
:	O
cystine	O
knot	O
peptides	O
,	O
cyclotides	O
or	O
lasso-peptides	O
such	O
as	O
microcin	O
J25	O
.	O
</s>
<s>
The	O
earliest	O
reported	O
synthesis	O
of	O
a	O
rotaxane	B-Algorithm
in	O
1967	O
relied	O
on	O
the	O
statistical	O
probability	O
that	O
if	O
two	O
halves	O
of	O
a	O
dumbbell-shaped	O
molecule	O
were	O
reacted	O
in	O
the	O
presence	O
of	O
a	O
macrocycle	O
that	O
some	O
small	O
percentage	O
would	O
connect	O
through	O
the	O
ring	O
.	O
</s>
<s>
To	O
obtain	O
a	O
reasonable	O
quantity	O
of	O
rotaxane	B-Algorithm
,	O
the	O
macrocycle	O
was	O
attached	O
to	O
a	O
solid-phase	O
support	O
and	O
treated	O
with	O
both	O
halves	O
of	O
the	O
dumbbell	O
70	O
times	O
and	O
then	O
severed	O
from	O
the	O
support	O
to	O
give	O
a	O
6%	O
yield	O
.	O
</s>
<s>
However	O
,	O
the	O
synthesis	O
of	O
rotaxanes	B-Algorithm
has	O
advanced	O
significantly	O
and	O
efficient	O
yields	O
can	O
be	O
obtained	O
by	O
preorganizing	O
the	O
components	O
utilizing	O
hydrogen	O
bonding	O
,	O
metal	O
coordination	O
,	O
hydrophobic	O
forces	O
,	O
covalent	O
bonds	O
,	O
or	O
coulombic	O
interactions	O
.	O
</s>
<s>
The	O
three	O
most	O
common	O
strategies	O
to	O
synthesize	O
rotaxane	B-Algorithm
are	O
"	O
capping	O
"	O
,	O
"	O
clipping	O
"	O
,	O
and	O
"	O
slipping	O
"	O
,	O
though	O
others	O
do	O
exist	O
.	O
</s>
<s>
This	O
dynamic	O
complex	O
or	O
pseudorotaxane	B-Algorithm
is	O
then	O
converted	O
to	O
the	O
rotaxane	B-Algorithm
by	O
reacting	O
the	O
ends	O
of	O
the	O
threaded	O
guest	O
with	O
large	O
groups	O
,	O
preventing	O
disassociation	O
.	O
</s>
<s>
The	O
partial	O
macrocycle	O
then	O
undergoes	O
a	O
ring	O
closing	O
reaction	O
around	O
the	O
dumbbell-shaped	O
molecule	O
,	O
forming	O
the	O
rotaxane	B-Algorithm
.	O
</s>
<s>
The	O
method	O
of	O
slipping	O
is	O
one	O
which	O
exploits	O
the	O
thermodynamic	O
stability	O
of	O
the	O
rotaxane	B-Algorithm
.	O
</s>
<s>
By	O
cooling	O
the	O
dynamic	O
complex	O
,	O
it	O
becomes	O
kinetically	O
trapped	O
as	O
a	O
rotaxane	B-Algorithm
at	O
the	O
lower	O
temperature	O
.	O
</s>
<s>
one	O
part	O
of	O
the	O
thread	O
is	O
then	O
threaded	O
to	O
the	O
macrocycle	O
,	O
forming	O
a	O
semi	O
rotaxane	B-Algorithm
,	O
and	O
end	O
is	O
closed	O
of	O
by	O
the	O
other	O
part	O
of	O
the	O
thread	O
forming	O
the	O
rotaxane	B-Algorithm
.	O
</s>
<s>
Rotaxane-based	O
molecular	O
machines	O
have	O
been	O
of	O
initial	O
interest	O
for	O
their	O
potential	O
use	O
in	O
molecular	B-Algorithm
electronics	I-Algorithm
as	O
logic	O
molecular	O
switching	O
elements	O
and	O
as	O
molecular	O
shuttles	O
.	O
</s>
<s>
Controlling	O
the	O
position	O
of	O
the	O
macrocycle	O
allows	O
the	O
rotaxane	B-Algorithm
to	O
function	O
as	O
a	O
molecular	O
switch	O
,	O
with	O
each	O
possible	O
location	O
of	O
the	O
macrocycle	O
corresponding	O
to	O
a	O
different	O
state	O
.	O
</s>
<s>
These	O
rotaxane	B-Algorithm
machines	O
can	O
be	O
manipulated	O
both	O
by	O
chemical	O
and	O
photochemical	O
inputs	O
.	O
</s>
<s>
Rotaxane	B-Algorithm
based	O
systems	O
have	O
also	O
been	O
shown	O
to	O
function	O
as	O
molecular	O
muscles	O
.	O
</s>
<s>
Studies	O
with	O
cyclodextrin-protected	O
rotaxane	B-Algorithm
azo	O
dyes	O
established	O
this	O
characteristic	O
.	O
</s>
<s>
The	O
enhanced	O
stability	O
of	O
rotaxane	B-Algorithm
dyes	O
is	O
attributed	O
to	O
the	O
insulating	O
effect	O
of	O
the	O
macrocycle	O
,	O
which	O
is	O
able	O
to	O
block	O
interactions	O
with	O
other	O
molecules	O
.	O
</s>
<s>
In	O
a	O
nanorecording	O
application	O
,	O
a	O
certain	O
rotaxane	B-Algorithm
is	O
deposited	O
as	O
a	O
Langmuir	O
–	O
Blodgett	O
film	O
on	O
ITO-coated	O
glass	O
.	O
</s>
<s>
When	O
a	O
positive	O
voltage	O
is	O
applied	O
with	O
the	O
tip	O
of	O
a	O
scanning	O
tunneling	O
microscope	O
probe	O
,	O
the	O
rotaxane	B-Algorithm
rings	O
in	O
the	O
tip	O
area	O
switch	O
to	O
a	O
different	O
part	O
of	O
the	O
dumbbell	O
and	O
the	O
resulting	O
new	O
conformation	O
makes	O
the	O
molecules	O
stick	O
out	O
0.3	O
nanometer	O
from	O
the	O
surface	O
.	O
</s>
<s>
Accepted	O
nomenclature	O
is	O
to	O
designate	O
the	O
number	O
of	O
components	O
of	O
the	O
rotaxane	B-Algorithm
in	O
brackets	O
as	O
a	O
prefix	O
.	O
</s>
<s>
Therefore	O
,	O
the	O
a	O
rotaxane	B-Algorithm
consisting	O
of	O
a	O
single	O
dumbbell-shaped	O
axial	O
molecule	O
with	O
a	O
single	O
macrocycle	O
around	O
its	O
shaft	O
is	O
called	O
a	O
[2]rotaxane,	O
and	O
two	O
cyanostar	O
molecules	O
around	O
the	O
central	O
phosphate	O
group	O
of	O
dialkylphosphate	O
is	O
a	O
[3]rotaxane	O
.	O
</s>
