Quantum chemical studies on the interactions of molecules and molecular clusters with graphyne and graphdiyne
R. S. Swathi

Graphyne and graphdiyne are new members in the family of carbon-based network materials obtained by introducing acetylenic units into the hexagonal frameworks of graphene. The carbon atoms in these lattices exist in sp and sp2 states of hybridization unlike the case of graphene, wherein all the carbon atoms are sp2 hybridized. The sub-units of these lattices have already been prepared and are found to have interesting nonlinear optical properties. However, preparing bulk graphyne and graphdiyne has been a challenge and it is only recently that graphdiyne films have been made. Attempts towards theoretical understanding of the electronic, optical and mechanical properties of bulk graphyne and graphdiyne have only begun and are in their infancy.

In our research group, we have initiated theoretical studies on understanding the interactions of graphyne and graphdiyne-based lattices with ions and molecules using density func- tional theory (S. Chandrashekar and R. S. Swathi, J. Phys. Chem. A, 117, 8632, 2013). However, our studies are limited by the existing computational resources. Thus, we have been able to consider only very small model compounds (molecules having ∼ 60 atoms) of the extended structures for our investigations, which typically run into 5-7 days on a modern workstation. The results obtained from these studies would have significant contributions from the edge effects. Therefore, we intend to carry out investigations on much larger sub-units of graphyne and graphdiyne (molecules having ∼ 200 atoms) and thereby avoid edge effects. Further, our objective is to investigate the adsorption of supramolecular network clusters formed by hydrogen bonding on the graphyne and graphdiyne lattices using density functional calculations. We also intend to extend our investigations to graphane, the fully hydrogenated form of graphene and other functionalized forms of graphene like graphene oxide and fluorographene. Many of the fundamental molecular and ionic interactions like non-covalent interactions, cation-π and anion-π interactions with these new extended materials are yet to be investigated. We hope that we can contribute significantly to this area of research.