Chemistry Reference
In-Depth Information
1
An introduction to molecular organic materials
Welch Schauspiel! aber ach! ein Schauspiel nur!
Wo fass ich dich, unendliche Natur?
What pageantry! Yet, ah, mere pageantry!
Where shall I, endless Nature, seize on thee?
Johann Wolfgang von Goethe
,
Faust
(Translation by G. M. Priest)
Broadly speaking, crystalline molecular organic materials (MOMs) are soft solids
with a 3Dperiodic distribution of organicmolecules exhibitingweak intermolecular
forces, their cohesion being essentially mediated by dipolar (permanent or fluctu-
ating charges), hydrogen bonding and
π
−
π
interactions. The molecules involved
in the formation of such materials may be of a purely organic nature (e.g., metal-
free) or based on hybrid organic-inorganic combinations (e.g., organo-metallicwith
transition metals). Solids can be built from molecules of a single species or binary
or ternary combinations, and inorganic molecules can also be introduced forming
hybrid organic-inorganic materials. Such regular solids are often seen by chemists
as supramolecular entities, the solid as a macromolecule, in spite of their discrete
character, while physicists tend to think in terms of a weakly interacting ordered
gas, with cohesion energies larger than about 0.2 eV per molecule (
20 kJ mol
−
1
),
1
the typical energies of noble gas crystals. Although describing the same objects,
the terminology used by chemists and physicists is usually distinct and scientific
discussions are not always fully synthesized, hindering the desired effective flow
of ideas. One of the objectives of this topic is to bring both scientific communities
to a common neutral playground to better understand the inherently interdisci-
plinary, rich, complex and exciting field of crystalline MOMs, which involves both
1
1eV
=
1.6
×
10
−
19
J
=
8065 cm
−
1
=
1.16
×
10
4
K
1 eV molec
−
1
100 kJ mol
−
1
.
1
