Xianxi Zhang

Infrared spectra of phthalocyanine and naphthalocyanine in sandwich-type (na)phthalocyaninato and porphyrinato rare earth complexes. Part 3. The effects of substituents and molecular symmetry on the infrared characteristics of phthalocyanine in bis(phthalocyaninato) rare earth complexes

The infra-red (IR) spectroscopic data for a series of 45 homoleptic unsubstituted and substituted bis(phthalocyaninato) rare earth complexes M(Pc)2 and M(Pc*)2 [M=Y, La...Lu except Pm; H2Pc=phthalocyanine; H2Pc*=2,3,9,10,16,17,24,25-octakis(octyloxy)phthalocyanine (H2OOPc) and 2(3),9(10),16(17),24(25)-tetra(tert-butyl)phthalocyanine (H2TBPc)] have been collected with resolution of 2 cm(-1). The IR spectra for M(Pc)2 and M(OOPc)2 are much simpler than those of M(TBPc)2, revealing the relatively higher symmetry of the former two compounds. For M(Pc)2 the Pc-* marker band at 1312-1323 cm(-1), attributed to the pyrrole stretching, and the isoindole stretching band at 1439-1454 cm(-1) are found to be dependent on the central rare earth size, shifting slightly to the higher energy along with the decrease of rare earth radius. The frequency of the vibration at 876-887 cm(-1) is also dependent on the rare earth ionic size. The metal size-sensitivity of this band and theoretical studies render it possible to re-assign it to the coupling of isoindole deformation and aza vibration. The nature of another metal-sensitive vibration mode at 1110-1116 cm(-1), which was previously assigned to the C-H bending, is now re-assigned as an isoindole breathing mode with some small contribution also from C-H in-plane bending. These assignments are supported by comparative studies of the IR spectra of substituted bis(phthalocyaninato) analogues M(OOPc)2 and M(TBPc)2. By comparison between the IR spectra of unsubstituted and substituted bis(phthalocyaninato) rare earth analogues and according to the IR characteristics of alkyl groups, some characteristic vibrational fundamentals due to the Pc rings and the substituents can be separately identified. In conclusion, all the metal size-dependent IR absorptions are composed primarily of the vibrations of pyrrole or isoindole stretching, breathing or deformation or aza stretching of the Pc ring.

Electrochemistry of homoleptic bis[3(4),12(13),21(22),30(31)-tetra(tert-butyl)-naphthalocyaninato] rare earth(III) complexes

The electrochemistry of homoleptic bis(naphthalocyaninato) double-decker complexes for the whole series of tervalent rare earths M(TBNc)2 (M = Y, La…Lu except Ce and Pm; H2TBNc = 3(4),12(13),21(22),30(31)-tetra(tert-butyl)naphthalocyanine) has been systematically studied by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Up to three quasi-reversible one-electron oxidations and four quasi-reversible one-electron reductions have been revealed for these double-deckers.The half-wave potentials of all oxidations and the first reduction for double-decker complexes are dependent on the size of the metal center. The difference between the redox potentials of the first and second reductions for MIII(TBNc)2, which represents the potential difference between the first oxidation and first reduction of [MIII(TBNc)2]−, lies in the range 1.09-0.95 V and gradually diminishes along with the lanthanide contraction, indicating increased π-π interaction in the double-deckers in the same order. Comparison of...