Metalated Porphyrins and Phthalocyanines on Surfaces: potential for environmental and energy applications

 

Porphyrins are planar aromatic molecules comprising a core
tetrapyrrolic macrocycle Molecular functionalization of the porphyrins has become
significant in synthetic chemistry, molecular electronics, and surface science High
symmetrical D 4 h nature of metalated porphyrins is of great interest in the
perspective of two dimensional assemblies on surfaces and three dimensional
frameworks Most of the transition metal elements can be incorporated into the core
macrocycle Such complex systems are widely investigated in the context of higher
order or dimensional arrangement of functionalized adsorbates on surfaces Recent
investigations on thermodynamic self assembly of porphyrins are significant in
illustrating the behavior of substrates on metallic surfaces Functionalized
porphyrin species are advantageous for photocatalysis, degradation, energy
conversion and storage, and metal pollutant detection The applications of surface
deposited porphyrin species are not widely investigated This would serve as a
potential mechanism for efficient surface processes for environmental and energy
applications In this study, porphyrins with metal centers Ni, V, Cu and Co and
phthalocyanines ( adsorbed to gold (Au 111 and highly ordered pyrolytic
graphite (HOPG 0001 surfaces are investigated Favorable binding sites of metal
centered octa ethyl porphyrins ( and Pc on the surfaces are investigated
Further, adsorption energy trends with different metal centers, surfaces and binding
sites and orbital hybridization driven charge redistribution are investigated based on
quantum mechanical density functional theory level calculations Density of states
of isolated MOEP, Pc and MOEP/ Pc Surface systems provide insights on energy
level alignment This study aims to demonstrate a systematic and comparative
analysis of the adsorbate surface interactions in terms of substrate conformations,
energy level alignment, local electronic structure and charge redistribution
employing periodic DFT calculations