Designing systems that offer stable single atom transition metal sites for reaction may lead to significant advancement in the next-generation catalyst. In this talk, we will discuss our recent effort in understanding and proposing two such systems which have motivated by experimental observation. In the first, our density functional theory (DFT) based calculations provide excellent agreement with the observations of Pt-dipyridyltetrazine complexes on the reconstructed Au(100) surface, in which single Pt atoms are stabilized by dipyridyltetrazine ligands. We find that these complexes form 1-dimensional chains aligned 45o with respect to the Au(100) reconstruction row and with the molecule-molecule distance of 6.93 Å. Bader analysis shows that Pt atoms are cationic with a charge of +0.75, indicating that the oxidation state of the Pt atoms is +2, close to that of Pt atoms in PtO. Furthermore, for Pt-di-pyrimidinyl-tetrazine complexes on the same surface, we find that the complexes form 1D chains that are parallel with the surface reconstruction row and that the distance between molecules are 5.88 Å. In addition, our computational screening of the propensity of several other metal atoms for assembling similar dipyridyltetrazine molecular chains show sufficiently large formation energies which suggest their stability. More importantly, the coordination centers of the dipyridyltetrazine chains constituted by Mo, Cr, Fe or Co atoms bind CO and O2 strongly, suggesting that these chains maybe potential candidates for CO oxidation catalyst. The guidelines obtained above will be compared to that gleaned from the coordination networks of 9, 10 dicyano-anthracene and diisocyano-anthracene on Cu(111). The impact of functional groups (N, CN, NC, NH2, COH, COOH) on the electronic structure of the coordination center, with and without a Cu adatom, will also be presented. Our results show that while the interaction between the naphthalene backbone and the Cu(111) surface is dominated by van der Waals (vdW) forces, in all cases considered the functional group forms a covalent bond with the Cu (ad)atom (on) of the surface. These results provide insights into the different surface coordination behavior of molecules with above-mentioned functional groups.

Computational design of metal-ligand coordination centers for catalytic applications

253rd National Meeting (2017)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.