Effect of metal substitution (Mg, Sc) and functionalization (H, F, NH2, CH3, OH, CHO, and COOH) on the absorption properties of phthalocyanines – A TDDFT study. (15th January 2020)

• Record Type: Journal Article
• Authors: Arokiyanathan, Agnes Lincy; Lakshmipathi, Senthilkumar
• Is Part Of: Polyhedron. Volume 176(2020)
• Publication Date: 2020-01-15
• Subjects: Magnesium -- Scandium -- Phthalocyanine -- TDDFT -- PDT -- Artificial photosynthesis; Chemistry, Inorganic -- Periodicals; Chimie inorganique -- Périodiques; Organometaalverbindingen; Anorganische chemie; 546.05
• DOI: 10.1016/j.poly.2019.114244
• Languages: English
• ISSNs: 0277-5387

Abstract

Graphical abstract: The electronic spectra of functionalized Magnesium and Scandium phthalocyanines were analysed theoretically. The absorption spectra show bathochromic shift in solvent phase and on Scandium doping. The intra molecular charge transfer occur in MgPc complexes while the absorption spectra of ScPc complexes are due to ligand to metal charge transfer. Abstract: This paper reports the results pertained to time dependent density functional theory studies on magnesium and scandium phthalocyanines that are hexadeca substituted with functional groups such as H, F, NH2, CH3, OH, CHO, and COOH. The gas phase optimizations are performed using three functionals such as B3LYP-D, CAM-B3LYP and PBE0 in LANL2DZ/6-31g** basis set. The vertical electronic excitations were formulated in gas phase as well as solvent phase with chloroform as a solvent by means of polarizable continuum model. The results show that B3LYP-D is best suited for the study of both Q and B band region since it correlates well with the experimental absorption spectra. The absorption spectra of MgPcs are mainly due to π-π* transitions while in ScPcs ligand to metal charge transfer is also seen. The absorption spectra show a bathochromic shift in solvent phase, on both Scandium doping and functionalizing the macrocyclic position with amine and hydroxyl group. Interestingly amine substitution induces Q band splitting, lifting the LUMO degeneracy. The red shift of the absorption spectra is due to the decrease in the HOMO-LUMO gap of the systems. The existence of Q and B band absorption range in the studied complexes indicate their utilization in the artificial photosynthesis and photo dynamic therapy devices.