Structures and Spectroscopic Properties of Bis(phthalocyaninato) Yttrium and Lanthanum Complexes:  Theoretical Study Based on Density Functional Theory Calculations

Abstract

Density functional theory (DFT) calculations were carried out to describe the molecular structures, molecular orbitals, atomic charges, UV-vis absorption spectra, IR, and Raman spectra of bis(phthalocyaninato) rare earth(III) complexes M(Pc)(2) (M = Y, La) as well as their reduced products [M(Pc)(2)](-) (M = Y, La). Good consistency was found between the calculated results and experimental data. Reduction of the neutral M(Pc)(2) to [M(Pc)(2)]- induces the reorganization of their orbitals and charge distribution and decreases the inter-ring interaction. With the increase of ionic size from Y to La, the inter-ring distance of both the neutral and reduced double-decker complexes M(Pc)(2) and [M(Pc)(2)](-) (M = Y, La) increases, the inter-ring interaction and splitting of the Q bands decrease, and corresponding bands in the IR and Raman spectra show a red shift. The orbital energy level and orbital nature of the frontier orbitals are also described and explained in terms of atomic character. The present work, representing the first systemic DFT study on the bis(phthalocyaninato) yttrium and lanthanum complexes sheds further light on clearly understanding structure and spectroscopic properties of bis(phthalocyaninato) rare earth complexes.

Theoretical study of NMR, infrared and Raman spectra on triple-decker phthalocyanines

“…In the case of Sc2(Pc)3 and Y2(Pc)3, there were symmetrical bridged-phase of ESP mapping on the upper, middle and bottom parts of phthalocyanine ring. This behavior suggests an influence of polarization and electronegativity, which is related to nuclear magnetic interaction and chemical shifts of 13 C-, 1 H-and 14 N-NMR on the phthalocyanine ring. The chemical shift of 14 N-NMR will depend on nuclear quadrupole interaction based on EFG and η under metal ligand crystal field.…”

“…The deformed structure without molecular symmetry resolved multi-degeneracy of energy levels near frontier orbitals, inducing absorption with a slight wide range of spectra of 808 nm and 746 nm, owing to π -π* transition of the phthalocyanine rings. A slight deform near the metal ligand crystal field will influence the magnetic parameters of chemical shift in 13 C-NMR, g-tensor, V-tensor in EFG, η and excited state process. UV-vis-NIR spectra at excited process were calculated by time-dependent (TD)-DFT.…”

“…Chemical shifts of 13 C, 1 H and 14 N-NMR in M2(Pc)3 were investigated by DFT using NMR with GIAO. Calculated chemical shifts of 13 N-NMR in V2(Pc)3 as referred by NH3 was slightly separated in the range of 120 ppm -250 ppm.…”

“…Mulliken atomic charges, electron density distribution and electrostatic potential (ESP) were estimated by Mulliken population analysis. Continuously, isotropic chemical shift of 13 V and 89 Y atoms were calculated by DFT using NMR using GIAO with hybrid function B3LYP and LANL2MB as basis set. The vibration modes in IR and Raman spectra were calculated by DFT using frequency mode.…”

“…Single-molecular magnetic properties of terbium(III)-phthalocyaninato quintuple-decker complex as compared with those of other multipledecker complexes (triple-decker and quadrupole-decker phthalocyanines) were studied to characterize the relationship between magnetic interactions on the phthalocyanine ring by X-ray crystallography and magnetic measurements. 10) Experimental study of nuclear magnetic resonance (NMR), ultraviolet-visible-near infrared (UV-vis-NIR), infrared (IR) and Raman spectra, Near edge X-ray absorption fine structure spectroscopy and density functional theory (DFT) calculations of double-and triple-decker phthalocyanines rare earth(III) complexes, M(Pc)2 (M = Y, La) has been studied [11][12][13]. Especially, magnetic interactions and magnetic parameters of isotropic chemical shift, principle gtensor, V-tensor in electronic field gradient (EFG) and asymmetry parameters (η) in multi-decker types of metal phthalocyanine complex has been investigated for controlling nuclear spin dynamics and molecular design of single molecular magnetism and NMR quantum computer.…”