Thank you, and good morning to everyone.
When I was asked to prepare this conference
I was a bit ‘undecided whether to present my research,
so difficult, or actually make you take an extraordinary journey
in what is a truly innovative branch
of chemistry, which is supermolecular chemistry,
driving the smallest car you can imagine,
that is a molecular machine.
But, before doing this, there is a need
to introduce the concept of nanotechnology,
and in fact I imagine that many of you know
that a nanometer is the billionth part of a meter.
And in particular, to give you an idea of the dimensions,
one of your hair is about 50,000 nanometers,
a cell or a red blood cell is about 8 nanometers,
up to a 2 nanometer membrane protein,
and to the smallest entity, for a chemist,
certainly not for a physicist, or the atom, only 0.1 nanometers.
Nanotechnology deals with manipulating matter at the nanometric level,
typically between the nanometer and the 100 nanometers.
There are basically two approaches to doing this.
Take a block, and actually cut it, cut it, cut it,
and finish it, until it reaches the macroscopic dimensions
this size of about 100 nanometers
and this is the “top-down” approach, more typical perhaps of physicists,
and instead a “bottom-up” approach, in which the chemist actually manipulates his own
atoms, molecules, from the scale of the single nanometer
until they are assembled,
to reach a scale of 100 nanometers, and this is the bottom-up approach.
Now, why did I decide to focus on molecular machines?
Because no more than 3 days ago, December 10, 2016,
these three gentlemen, friends, colleagues, who have a little ‘inspired so much
in my career,
received the Nobel Prize for Chemistry,
precisely for the design and construction of molecular machines.
I wanted to dedicate this intervention to them precisely because, as I said,
they inspired a lot of my research,
and in fact I met them in my career so many times,
last, for example, summer 2016.
And, basically, a molecular machine is a molecular device
made of many small gears, that is, many molecules assembled together
just to remember a macroscopic mechanism
able to perform movements in an extremely controlled manner.
And if it is already difficult to assemble a real, macroscopic machine,
think about the work of engineers,
imagine instead how difficult it can be
to assemble molecules in a way that makes sense,
to generate movement,
although they could not absolutely see the molecules with their own eyes.
And in particular, for example
Professor Jean-Pierre Sauvage of the University of Strasbourg,
it actually introduced as early as the early 1980s
a new type of molecules called Catenano,
in which he actually made a donut-shaped molecule,
but above all he took two donuts
and he totally chained the two donuts
creating a new molecule called Catenano.
They are the two links in a chain linked permanently,
proving in fact that these two rings
they can rotate freely, independently of each other:
a new molecule like that was born.
Later, instead, Fraser Stoddart, of the University of Illinois,
Northwestern University,
has instead created a new type of molecule, which is the Rotassano.
Imagine taking a donut again,
a straw, plug the ends,
you have once again realized a new molecule
due to the assembly of several molecules,
which in turn can no longer be paraded to each other
because it has big bulky groups at the ends,
so in fact the straw can no longer be removed from the donut.
This is the Rotassano, which thus proved
that for example the donut can move around the axis
just like a wheel normally does
and just Fraser Stoddart, introducing along the straw
two types of groups with a different electronic density,
he made this ring, this donut,
it could move in a controlled way by the light,
or from a chemical impulse, or from an optical impulse,
between a type 0 station for example, and a type 1 station.
You have thus created a binary code at the molecular level,
which is actually how our computer works,
imagine taking all these Rotassani,
to support them on a surface, to make them all work together,
you have taken the first step towards the molecular computer.
Instead, Ben Feringa, of the University of Groningen in the Netherlands,
he has always worked on the concept of molecular motor
using a single molecule instead,
but allowing to control the movement of some groups,
so we say, chemical, compared to other chemical groups,
through a rotation of fact around a chemical bond,
controlling it this in a unidirectional way,
so for the first time there was a movement
not random in one way or another, but one-way,
and in fact this once again controlled by an external impulse
chemical, optical or electrical.
And it reminds me a lot of this the classic Tric-Trac,
very noisy children’s game,
in which you have in fact an axis, which is the stator,
and a rotor that rotates around the axis.
So why not think about molecular Tric-Trac
supported on a gold surface, in which, for example
we supported Feringa molecules,
and then it is possible in a unidirectional way
control the movement by creating, for example, a transport system
that thanks to these molecules that turn,
they can transport intelligently
something else under a precise impulse.
All right, all right, but what’s the use?
The typical question I often receive is:
But what are these complicated molecules for?
Well, I tell you, at the moment they do not need anything at all,
they are simply beautiful, very difficult to summarize,
but why not push yourself with your imagination?
For example Fraser Stoddart conceived
the first molecular lift,
then a chain linked to three stations, or better, to three Rotassans:
imagine you can actually go from a 0 to a 1 floor,
in a perfectly controlled manner,
making a wonderful journey of 0.7 nanometers.
Well, but once again all these molecular lifts are supported
on a surface and in fact you have made something
that can resemble an artificial muscle fiber.
While the subject a little ‘today is the molecular machine,
will we succeed then?
we heard first about beautiful aircrafts,
but will we ever manage to drive a molecular machine?
Where by molecular machine we mean in fact,
as did Ben Feringa,
an axis on which 4 wheels have been supported,
4 wheels able to move unidirectionally, synchronously,
through a fuel that is chemical, or electric, or optical,
and in fact this machine to move on a surface,
in a totally controlled way;
surface, for example, which may also be the fabric,
or the blood vessel of our body,
where this intelligent machine can transport
particularly important baggage such as life-saving medicines.
So why not go with the imagination to hypothesize something futurable,
now the chemistry available to do this is there.
But I would like to take a little step back,
I would also like to pay homage to another person, another great man
I owe so much in my career, because it was a source of inspiration
right at the beginning, that is when a graduate has to understand what he wants to do in life.
And reading the book by Jean-Marie Lehn, Nobel Prize in Chemistry in 1987,
I realized I wanted to do supramolecular chemistry.
What is supramolecular chemistry?
Jean-Marie Lehn introduces another concept:
molecules are not individuals, but we must think of collectivity,
so the molecules interact with other individuals
within the same community in a way …
with great affinity or absolutely with great dislike.
The supramolecular chemistry is just trying to aggregate the molecules
in a controlled manner, making them interact
through intermolecular interactions.
And I’m sure many of you know the most basic inter-molecular interaction,
which is the one on which life is based, which is the hydrogen bond,
and it is precisely the electrostatic interaction used by the water molecules
that self-assemble in a perfectly directional and geometric way,
then build and result in the water we drink,
which is liquid at room temperature,
but that below zero degrees Celsius
leads to these beautiful, perfectly organized geometric structures,
like that of the snow crystal.
And in particular the hydrogen bond is also the intermolecular interaction
that binds the double strand of DNA in this structure
three-dimensional helix to which we owe life,
and have you ever wondered why, then, life is stored
in a weak interaction?
Because the DNA must open allowing the mutations,
repair errors, and allow the evolution of man.
Even man has tried to imitate nature, and it’s not simple,
nature has had millions of years available to evolve,
but also the man, the chemist, tried to get inspiration
from macroscopic objects reproducing, for example, the World Cup
and that, as in the case of having supported a cyclic molecule,
a flask made of carbon atoms, a fullerene, on a calixarene,
that is, a chalice-shaped molecule, has been realized;
as you can see, a totally molecular World Cup
to pay homage to the French team that won the World Cup in 1998.
Or, again, Fraser Stoddart has concatenated as many as 5 chemical rings
to be able to reproduce the 5 Olympic rings:
once again, in fact, molecules that do not have immediate use,
but they certainly have a great aesthetic beauty.
However, new intermolecular interactions are discovered daily,
and I am pleased to be able to mention an intermolecular interaction
which was discovered here at the Polytechnic.
Because we are chemists we need to experiment …
see an ongoing experiment:
we have actually put these two molecules together
that you see represented in the slide,
in particular, the two molecules do not physically touch each other
but from the vapor phase, evaporating, they come into contact,
create a new intermolecular interaction,
generating as you can see on the needle tip of the new crystals.
These new crystals are supramolecular entities
consisting of the two molecules that come together,
they constitute something new, of a totally new material,
previously non-existent, in a totally reversible manner,
not losing their properties.
And this interaction has been studied here at the Polytechnic.
What can we do? We also started doing
something peculiar, something aesthetically beautiful,
and for example we tried to … we asked ourselves if it was possible
reproduce the Borromean rings,
and the Borromean rings are one of the mathematical topologies
more complex to reproduce
because in fact there are three rings linked together,
but in reality, try playing with this representation,
if you simply cut and remove any of the three colors,
the other two are simply parallel,
it is only the third that holds all three together.
Then precisely for this meaning of force only in unity
the Borromean rings have been a symbol in different cultures,
from the Scots to the Vikings, and obviously from the Borromeo family
which governed Lombardy and Milan between 1400 and 1800.
We wondered? It is possible to replicate this at the molecular level
juxtaposing through intermolecular interactions,
in fact, our molecules?
Well, after so many attempts we even managed it,
and as you can see, this is a representation of a Borromean ring
totally replicated at the molecular level,
you can play and check that it really has Borromean properties,
because if for example cut any one,
for example, the red ring, the yellow ring and the blue ring
they simply slip out,
so we replicated a symbology that has existed for hundreds of years
at the molecular level.
But why is it important to study this intermolecular interaction?
Well, know that your body is also currently making a halogen bond,
and in particular, for example, see T4, thyroxine, is the thyroid hormone,
so our thyroid works by binding this molecule, this thyroxine,
which has 4 iodine atoms that are bound to your receptor
exactly the same way we saw before.
But because nature has chosen another intermolecular interaction
instead of the ubiquitous hydrogen bond?
Precisely because he needed to distinguish from the background noise
a highly important function,
highly specific, like that of the thyroid.
And why is it important to study these interactions?
Well, because there are so many industrial molecules,
many pollutants, such as this PBDE 73 molecule,
that is a pollutant that just goes to disrupt the balance of the thyroid
because as you see it is structurally identical, it has 4 bromine atoms,
and this has made it possible to rationalize that many pollutants in the environment,
because this molecule is widely used for example as a flame retardant,
or in electronic components, or in furniture,
every day we breathe this type of molecule
that just interferes with the thyroid mechanism,
exactly the same way.
Furthermore when we are stressed we produce hydrogen peroxide,
hydrogen peroxide with chloride and bromide from the diet,
they go to halogenize the proteins;
the proteins, once halogenated, do not work anymore,
so it is important to study these mechanisms because these halogenated molecules
they have been studied and found in many diseases,
like cystic fibrosis, asthma, allergy, even skin aging,
and we are currently conducting an extremely ambitious project
for the verification of these markers also in Alzheimer’s disease.
With this I leave you, I hope I have communicated to you
a little ‘what is the newspaper of the chemist,
that actually plays with molecules just as if it were, I would say,
a large molecular Lego at the nanometric level;
and I would like to leave you with a couple of messages.
The first is: chemistry is not just what pollutes, or what it stinks,
chemistry produces these molecules of an important aesthetic beauty,
but think of developments such as nanomedicine
this type of molecules could have.
And, two, I hope I have made you grasp
the extraordinary nature of the researcher’s work,
the extraordinary nature of the research that leads
and above all of the great men we have seen, the Nobel Prize winners,
that inspire many new generations
and who try in some way to imitate the nature that,
aimeh, still remains the best chemist of all
Thank you.
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