‘chemistry beyond the molecule’
‘the chemistry of the non-covalent bond’
‘non-molecular chemistry’
NON-COVALENT intermolecular forces include electrostatic interactions, ion-dipole interaction, dipole-dipole interaction including vander Waal’s forces etc. This means beyond molecular chemistry which is based on covalent bond there lays a field of supramolecular chemistry, which uses intermolecular bonding through non-covalent interactions. This allow individual molecules to held together with non-covalent intermolecular forces to form a bigger unit called SUPRAMOLCULE, where individuals having its own organization, their stability and tendency to associate or isolate.
These intermolecular forces also include hydrogen bonding as HF exists as dimer, water shows an exceptional high melting and boiling point so does sulphuric acid, Or the comparison of the basic nature of ammonia and phosphine and their stability.
There are several excellent books on this subject. "Supramolecular Chemistry", Jean-Marie Lehn, VCH, 1995 is a nice option to start with. You can fin a modern view of the subject is his review "Toward complex matter: Supramolecular chemistry and self-organization" published in Proc. Nat. Acad. Sci. USA 2002, 99, 4763–4768.
Supramolecular chemistry a field of chemistry beyond that of molecules and focuses on the chemical systems made up of a discrete number of assembled molecular subunits or components. The forces may vary from weak to strong. This type of chemistry examines the weaker and reversible non-covalent interactions between molecules. The study of non-covalent interactions gives understanding of many biological processes. Supramolecular research is often carried out in biological systems.
Supramolecular chemistry is the study of systems involving aggregates of molecules or ions held together by non-covalent interactions, such as electrostatic interactions, hydrogen bonding, dispersion interactions and solvophobic effects.
Just a few comments to complement the definitions already given.
The degree of interaction between the system components can really differentiate between what is molecular or supramolecular. Furthermore, from a functional viewpoint , is very important to consider how subunits of the system behaves when stimulated (e.g. light ). In the case of stimulation by photon, a system A-B can be considered a supramolecular species if the light absorption lead to a localization of the excited state on either A or B, or cause a transfer of electron from A to B (or viceversa). Otherwise, when the excited state are significantly delocalized, the species may be considered as a supermolecule (or large molecule).
A problem is that "supramolecular" usually includes coordination bonds which in this case sort of make the concept and oxymoron as coordination compound form molecular or extended compounds by significant covalent interactions. Beautiful chemistry though...
In general chemistry, a molecule or compound formed by the covalent bonds between atoms. But in supramolecular chemistry there does not exist a covalent bond, only non covalent interactions such as electrostatic interactions, hydrogen bonding, dispersion interactions and cation-pi interactions present between molecules or ions.
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