Adsorption of diatomic molecules on iron tape-porphyrin: A comparative study

Abstract

We investigated the adsorption of diatomic molecules, CO, NO, and O 2 , denoted by XO on iron tapeporphyrin ͑FeTP͒ using first-principles calculations based on density functional theory. In this work, we present the structure and electronic properties of iron tape-porphyrin and its complexes with CO, NO, and O 2 . The binding of such diatomic molecules to FeTP gave rise to significant changes on both the geometric structure and electronic properties of FeTP. We found that in all FeTP complexes with diatomic molecules, the Fe atom moves out of the porphyrin plane toward the adsorbed molecule. The energy of the iron-diatomic molecule bond increases in the order of Fe-O 2 ͑0.554 eV͒ Ͻ Fe-CO ͑1.225 eV͒ Ͻ Fe-NO ͑1.719 eV͒. At its stable position, the Fe-X-O angle increases in the order of Fe-C-O Ͼ Fe-N-O Ͼ Fe-O-O. The changes in geometric structure are in accordance with other density functional theory calculations and experimental results for porphyrin molecule. As regards the electronic properties, there appears an energy gap between the conduction band and valence band in CO-adsorbed and NO-adsorbed cases with a more pronounced energy gap in the former, while none was observed in the O 2 -adsorbed case. We attribute these changes in electronic properties to the strong interaction involving the d orbitals of the Fe atom and the * orbitals of diatomic molecules. Specifically, for the CO and NO adsorbed on FeTP cases, the change in electronic properties is attributed to the strong hybridization of d xz and d yz orbitals of the Fe atom and * orbitals. For O 2 adsorbed on FeTP, the hybridization of the d z 2 orbital of the Fe atom and * orbitals plays the key role in O 2 -iron tape-porphyrin interaction.

DFT+U study on the oxygen adsorption and dissociation on CeO2-supported platinum cluster

“…HC conversion: HC + O 2 → CO 2 + H 2 O) and so, an understanding of the interaction of the metal/metal oxide system with O 2 is imperative. To date, there are numerous researches on the adsorption and dissociation of O 2 molecules on the organic systems and the bimetallic surfaces [13][14][15] but very few have been done on noble metal clusters or noble metal cluster/metal oxide, for instance, Pt cluster on CeO 2 . Yoon et al [16] investigated the molecular and dissociative adsorption of O 2 on Au clusters without the presence of metal oxide support using density functional theory (DFT).…”

Theoretical Study on The Adsorption of NO on Metal Macrocycles, Metal=Mn,Fe,Co,Ni,Cu,Zn

“…This suggests an important role of unoccupied d orbitals in the interaction with half occupied π* orbital of NO molecule. It is necessary to mention that the adsorption energy of NO on MPc are quite close to the adsorption energy of NO with metal tape-porphyrin [11][12][13][14]. This is because of the similarity in structure of phthalocyanine and porphyrin, especially the inner part (N ring, C ring).…”

Structure, Properties, and Reactivity of Porphyrins on Surfaces and Nanostructures with Periodic DFT Calculations

“…Ligand binding on porphyrin nanowires were also studied using PDFT simulations. Binding of NO molecule to metal tape-porphyrins [161][162][163] with PDFT calculations reveal molecular structure of metal tape-porphyrins has negligible change upon ligand binding but considerable change in the electronic structure was observed. Additionally, a significant band gap reduction has been observed upon NO ligand binding.…”