Distribution of the unpaired electron in neutral bis(phthalocyaninato) yttrium double-deckers: An experimental and theoretical combinative investigation

Abstract

ABSTRACT:The location of the unpaired electron in neutral bis(phthalocyaninato) yttrium doubledecker complexes, with different substituents, has been studied on the basis of both experimental methods and density functional theory (DFT) calculations over the molecular structures, atomic charges, electronic absorption, infrared spectra, and electron paramagnetic resonance. The results reveal the location of the unpaired electron mainly on the carbon atoms of both tetrapyrrole chromophores with the population distribution obviously affected by the peripheral substituents. KEYWORDS: phthalocyanine, yttrium, double-decker, unpaired electron, density functional calculations.◊ SPP full member in good standing * Correspondence to: Dongdong Qi, email: qdd@ustb.edu.cn (DQ), Ming Bai, email: ming_bai@sdu.edu.cn (MB).† These authors contributed equally to this work.

Solvothermal Synthesis of Rare Earth Bisphthalocyanines

“…The spectra of all the complexes studied here in powder form show a strong and sharp isotropic Landé signal around a g -factor of 2.0 with a peak-to-peak linewidth of 0.2 mT, which is attributed to the 1/2 spin radical. This result is additional proof of the successful synthesis and underscores the paramagnetic nature of these rare earth sandwich structures [ 22 , 27 , 44 ].…”

“…Fourier-transform infrared spectroscopy (FTIR) was employed to detect the characteristic features of the unsubstituted MPc 2 [ 17 , 18 , 19 ]. As depicted in Figure 1 a, the spectra of the four rare earth double-decker phthalocyanines exhibit the characteristic vibrational modes of phthalocyanines ligands in the region of 500–1800 cm −1 reported in the literature [ 17 , 18 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 ]. Notably, five main IR absorptions with strong and medium intensity were observed in all four spectra.…”

“…The highest intensity band at 731 cm −1 is attributed to C-H out-of-plane bending, while the absorption at 1001 cm −1 is assigned to the pyrrole N in-plane bending of the phthalocyanine ligand. The band at 1066 cm −1 is due to the coupling of the isoindole deformation and the aza group stretching (C=N), and the ones at 1311 and 1443 cm −1 arise from pyrrole and isoindole stretching [ 20 , 21 , 27 ]. Another band typical of these complexes is the weak intensity feature at 1117 cm −1 that corresponds to an isoindole breathing mode with small contributions from C-H in-plane bending [ 20 , 21 ].…”

“…It is important to mention that the electronic absorption of phthalocyanines depends on the chemical environment such as the type of solvent and its interaction with rare earth metal complexes. Hence, some discrepancies can be found between the UV-vis spectra of MPc 2 complexes in thin films, solution and solid pellets [ 22 , 23 , 24 , 26 , 27 , 37 , 38 , 39 , 40 , 41 , 42 , 43 ]. The spectra in Figure 4 exhibit the two main characteristic bands of phthalocyanines, the Q and the B or Soret bands [ 26 , 39 , 40 ].…”