Metal-dipyridyltetrazine chains with single metal coordination site: insights from first principles calculations

Duy Le, Naseem Ud Din and Talat S. Rahman

Deparment of Physics, University of Central Florida, USA

Creation, stabilization, characterization and control of single atom transition metal sites on surfaces may lead to significant advancement of the next-generation catalyst. Motivated by the experimental results of Skomski et al.,1 we have performed density functional theory based calculations of Pt-dipyridyltetrazine complexes on the reconstructed Au(100) surface to 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. This amount of charge is in accord with that on Pt atoms in PtO, as determined by a similar Bader analysis, and indicating that the oxidation state of the Pt atoms in the above Pt-dipyridyltetrazine network is closer to that of Pt atoms in PtO, which is +2, than in Pt3O4 or PtO3. This result is in excellent agreement with XPS data.1 In addition, our computational screening of the propensity of several other metal atoms for assembling similar dipyridyltetrazine molecular chains show sufficiently large (from 4.8 eV to 6.9 eV) 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 are potential candidates for CO oxidation catalyst. Details of reaction pathway (energetic and kinetic) of CO oxidation on the chains will be also presented and discussed.

*Work supported in part by NSF Grant CHE-1310327

1. D. Skomski, C.D. Tempas, K.A. Smith, and S.L. Tait, “Redox-Active On-Surface Assembly of Organic Chains with Single-Site Pt(II),” Journal of the American Chemical Society 136, 9862-9865 (2014).