Theoretical Chemistry: How We Help and Guide Experimentalists

The importance of theoretical modeling and computations is hard to be overestimated in the modern scientific world. The field of chemistry is not staying away from the mainstream. Theoretical chemistry is now well-developed and is an extremely fast growing area of science. New tools of theoretical and computational chemistry allow scientists to better understand and, what is more important, to predict properties and reactivity of newly synthesized molecules and bulk materials as well as to shed light on previously known experimental observations. In my talk, I will show a few examples how modern theoretical chemistry can help and guide experimentalists on the way to achieve promising results. My talk consists of three parts: (i) exploring the new chemistry of heavier analogs of N-heterocyclic carbenes; (ii) SO₂ as one more Janus-face ligand; and (iii) new results in the chemistry of open-geodesic polyaromatic hydrocarbons (buckybowls). The first part of my talk will be about new experimental achievements in the field of heavier analogs of N-heterocyclic carbenes (NHCs) or, more precisely, about how properly performed theoretical modeling can help in understanding results of experiment. The new type of Ge-, Sn-, and Pb-analogs of NHC stabilized by donor-acceptor interactions will be considered as pronounced examples.

In the second part, I will consider a theoretical exploration of coordination chemistry of SO₂, a small molecule that belongs to the important group of ambiphilic Lewis acids-bases with pronounced geometrical signatures. Molecules of this type may function as either electron-donors or acceptors through the same atom, but adopt different shapes depending on whether they act as Lewis acid or Lewis base. This example represents the case when a fresh look at known systems can results in better understanding of their properties and open new synthetic perspectives.

The last part will be devoted to new results in the field of buckybowls showing how efficient the combination of theoretical and experimental efforts can be. This class of bowl- and basket-shaped polyarenes is growing rapidly. Their potential applications range from rational design of fullerenes, nanotubes and their endohedral compounds to supramolecular architectures, for they can act as molecular clips and tweezers or even potential material for new-type Li-batteries. Previously, we have shown that the theoretical limit for Metal:C ratio for graphene-based materials (=1:5) can be jumped over in the case of buckybowls (for simplest corannulene =1:6). In my talk I will show that, when appropriately guided by theory (using its predictive power!), the limit can be shifted even further. The discovery of what we called “clamshell effect” (dramatic influence of alkali metal cation size on geometry of aggregates) was augmented by the new record in ⁷Li-NMR spectroscopy.