Electrical Characteristics of Cobalt Phthalocyanine Complexes Adsorbed on Graphene

Abstract

We investigate, at a density functional level, the electric characteristics of 18 complexes of cobalt phthalocyanine (CoPc) and cobalt tetraaminephthalocyanine (CoTAPc) adsorbed on graphene functionalized with CO 2 À or CO moieties. Three models of graphene molecules are used, pristine, defect, and vacancy, leading to 12 complexes with CO 2 À functionalized graphene and 6 complexes with functionalized CO graphene. The molecular structures of the optimized complexes feature covalent adsorption CoÀO lengths of ∼1.9À2.1 Å and CÀN lengths of ∼1.4 Å in parallel, perpendicular, and coplanar structures of graphene with phthalocyanine. All these conformations have a direct effect on the electronic characteristics of the complexes. Binding energies calculated for the interaction between functionalized graphene and phthalocyanine show that structures with defects and vacancies have lower energies than pristine graphene. In particular, we found that complexes having a graphene-CO linked to phthalocyanine by an amide bond are of highest stability (by ∼130 kcal/mol) and the formation of complexes with CO 2 À functionalized graphenes takes place preferably when involved with CoTAPc (by ∼20 kcal/mol). Frontier molecular orbitals (HOMO and LUMO) suggest that several of these complexes behave as charge transfer compounds with phthalocyanine as an electron donor and graphene as an electron acceptor, thus these complexes could behave as sensors because of the absorption properties of phthalocyanine in the UVÀvis region. The calculated currentÀvoltage characteristics show that electron transfer is preferably favored in complexes with parallel structure and with pristine graphene CO 2 À functionalization (∼7 μA) when both conjugates, graphene and phthalocyanine, face each other. The latter implies the transfer of charge through a πÀπ setting. However, the presence of defects and vacancies, for this face to face structure, shows lower electron transfer, having G-Def and G-Vac similar values of electron transfer. The conduction is very low for complexes with high stability (usually the coplanar structures) and with charge transfer features, i.e., those in which the HOMO and LUMO are in separated parts of the complex (usually the perpendicular and the coplanar structures). This study shows that cobalt phthalocyanine conducts electrical current toward graphene through a covalently attached CO 2 À to the graphene.

Systematic study of transition-metal (Fe, Co, Ni, Cu) phthalocyanines as electrocatalysts for oxygen reduction and their evaluation by DFT

“…15,18,23 Besides, the interaction between TMPc and supports also can affect the HOMO of TMPc, which probably improve the TMPc catalytic activity for ORR. 29,39 In common with other work, our results reveal that CuPc is beneficial to degradation of H 2 O 2 . 25 Combined with our theoretical analysis and other theoretical explanation, even if the high ΔETM-OO is detrimental to holding the two O atoms, the proper R TM-N of CuPc could lead the linear N-Cu-N structure conveniently to drag the two H atoms away by the two N atoms.…”

“…The use of the LANL2DZ has been successfully applied in the past for other transition metals. 29 In order to evaluate the reliability of calculation method, the structures of TMPc were all optimized, and the calculated properties of optimized TMPc are listed in Table S1. The calculated distances R TM-N , which stands for bond length between the central metal atom and the nearest neighbouring N atom, are mainly investigated to prove the reliability of the calculation method.…”

Some mechanistic insights into the action of facilitating agents on gas permeation through glassy polymeric membranes

“…Kuraoka et al reported an increase in selectivity, but a decrease in permeability with CoPc supported porous glass. Formation of a superoxide adduct between O 2 and CoPc has also been reported . Shoji et al showed a continuous increase in selectivity with Co(II) porphyrin complex loading, in a Nafion membrane.…”

Quantum chemical studies of porphyrin‐ and expanded porphyrin‐based systems and their potential applications in nanoscience. Latin America research review

“…The same modeling was used with success for complexes containing phthalocyanines . I‐V curves calculated at the M06/6‐31G(d,p) level of theory showed that the complexes with N‐doped graphene present the maximum current in the direction P → G, followed by complexes with B‐doped and PHP‐doped graphene.…”

“…The same modeling was used with success for complexes containing phthalocyanines. [32][33][34] I-V curves calculated at the M06/6-31G(d,p) level of theory showed that the complexes with N-doped graphene present the maximum current in the direction P ! G, followed by complexes FIGURE 1 Molecular structure of porphine indicating the three positions for substitution FIGURE 2 Electrostatic potential mapped onto total electronic density for two applied bias voltages.…”