Definition, types of nanomachines and nano car

1. MOLECULAR NANOMACHINES
Dr. P. SAMUEL
Asst. Professor of Biotechnology

2. Introduction
• A machine is any device that transmits or modifies energy, and in general speech
the word "machine" generally implies that the energy is transformed into some kind
of mechanical work.
• Nature has been doing it forever - muscle contractions are driven by the ATPase
activity of the protein myosin interacting with another protein called actin.
• The challenge for organic chemists is in actually designing and building a
molecular machine that can perform a specified task.
• In fact, nanostructures are just molecules or noncovalent clusters of molecules.
They have properties determined by their structures just like every other molecule.
Some are likely to be harmful while others may be helpful.

3. Nanocars
• In 2005 Tour's laboratory published the synthesis of the first nanocar - a molecular
machine that moved over a gold metal surface by rolling on wheels.
• The synthesis of this molecule took Tour and his students 8 years, but since then his
laboratory has produced several other nanovehicles of various sorts.
• It has the molecular formula C430H275O12 and a molecular weight of 5633.78.
• The "wheelbase" (length) of the nanocar is about 2.1 nm, and the "track" (width) is
3.3 nm.
• The nanocars use roughly spherical molecules called "buckminsterfullerenes" as
wheels.
• Each "buckyball" is a 60-carbon truncated icosahedron made up of aromatic rings.
• The axles and chassis consist of phenyl rings and alkyne units.
• It was necessary to include several C10H21chains on the axle/chassis units to give
the nanocars solubility in typical organic solvents for handling and processing.

4. • When the synthesis was complete, the nanocars were dissolved in toluene and the solution
was applied to a freshly-prepared and crystallographically defined layer of gold atoms under
high vacuum.
• The nanocars did not move until the surface was heated above 170 °C.
• At that temperature they began to roll forwards and backwards and to pivot.
• The STM images shown were taken at 200 °C.
• When the temperature reached 225 °C the motions became so fast and erratic that STM could
not longer observe the nanocars.

5. MOLECULAR MOTOR
Molecular motors are biological molecular machines that are the essential agents of
movement in living organisms.
In general terms, a motor is a device that consumes energy in one form and converts it
into motion or mechanical work; for example, many protein-based molecular motors
harness the chemical free energy released by the hydrolysis of ATP in order to
perform mechanical work.

6. Molecular propeller
• Molecular propeller is a molecule that can propel fluids when rotated, due to its special
shape that is designed in analogy to macroscopic propellers.
• Molecular propellers can be rotated by molecular motors that can be driven by chemical,
biological, optical and electrical means, or various ratchet-like mechanisms.
• Future applications of these nanosystems range from novel analytical tools in physics and
chemistry, drug deliveryand gene therapy in biology and medicine, advanced nanofluidic lab-
on-a-chip techniques, to tiny robots performing various activities at the nanoscale or
microscale.

7. MOLECULAR SWITCH
• A molecular switch is a molecule that can be reversibly shifted between two or
more stable states.
• The molecules may be shifted between the states in response to environmental
stimuli, such as changes in pH, light, temperature, an electric current,
microenvironment, or in the presence of ions and other ligands.

8. Molecular shuttle
• A molecular shuttle in supramolecular chemistry is a special type of molecular
machine capable of shuttling molecules or ions from one location to another.
• This device is based on a molecular thread composed of an ethyleneglycol chain interrupted
by two arenegroups acting as so-called stations.
• The terminal units (or stoppers) on this wire are bulky triisopropylsilylgroups.
• The bead is a tetracationic cyclophane based on two bipyridine groups and two para-
phenylenegroups.
• The bead is locked to one of the stations by pi-pi interactions but since the activation
energy for migration from one station to the other station is only 13 kcal/mol (54 kJ/mol) the
bead shuttles between them.
• The stoppers prevent the bead from slipping from the thread. Chemical synthesis of this
device is based on molecular self-assembly from a preformed thread and two bead fragments
(32% chemical yield).

9. Molecular tweezers
• The term "molecular tweezers" was first used by Whitlock.
• Molecular tweezers, and molecular clips, are host molecules with open cavities capable of
binding guest molecules.
• The open cavity of the molecular tweezers may bind guests using non-covalent bonding
which includes hydrogen bonding, metal coordination, hydrophobic forces, van der Waals
forces, π-π interactions, and/or electrostatic effects.
• These complexes are a subset of macrocyclic molecular receptors and their structure is that
the two "arms" that bind the guest molecule between them are only connected at one end
leading to a certain flexibility of these receptor molecules (induced fit model).