Structural and electronic properties of covalently functionalized 2-aminoethoxy-metallophthalocyanine–graphene hybrid materials: a computational study

Abstract

The formation of a strong covalent bond between graphene and 2-aminoethoxy metallophthalocyanine (AEMPc) with the metal atom (M) being Zn, Fe, and Ni is established from density functional theory (DFT) based calculations at the B3LYP/6-31G(d)/LANL2DZ level of theory. The optimized structures of the hybrid complexes, represented by AEMPc–graphene, are reported. The projected density of states (PDOS) spectrum of each molecule has been calculated to explore the change in the HOMO–LUMO gap due to anchoring of AEMPc to graphene. The IR peak-positions and intensities obtained for the newly formed C–H and C–N bonds confirm the covalent link between the two moieties. The computed Raman spectra of the hybrid complexes show some changes in the relative intensities of D and G bands of graphene in accordance to those observed experimentally in a similar graphene based hybrid material. TDDFT calculations are carried out to study their absorption spectra in DMF solvent. For all three metal atoms in the composite molecules, there appears a charge transfer band in the range 600–630 nm. Three long-range corrected functionals such as M06-2X, CAM-B3LYP, and wB97XD are used to compare the results with those of the hybrid B3LYP functional.