Phthalocyanine electronic spectra

The first investigation into the excited states of ZnPc based on first-principles methods is the TDDFT/SAOP study by Ricciardi et al [135], where the UV-vis and the vacuum ultraviolet region of the electronic spectrum of ZnPc are described in detail. Subsequently, Nguyen and Pachter, in the context of a TDDFT/B3LYP study of the electronic spectroscopy of the zinc tetrapyrrole series [140], ZnP, ZnPz, ZnTBP, and ZnPc, came to a somewhat different interpretation of the Uv-vis spectrum of this phthalocyanine. 

Dilithium phthalocyanine is obtained as dark-blue crystals. The compound has high thermal stability, as is typical of many phthalocyanines. It is soluble in acetone, giving a deep-blue solution that deposits phthalocyanine when in contact with even trace amounts of water. The material is also soluble in ethanol and tetrahydrofuran, but it is insoluble in diethyl ether, hexane, or chloroform. Solutions of the dilithium complex in ethanol react rapidly and quantitatively with a variety of metal salts to give the metallophthalocyanines, which precipitate, in very pure form, from solution. The electronic spectrum contains the bands (acetone solution) 370 (e = 24,800), 596 (e = 17,300), 630 (e = 16,100), 655 nm (e = 11,100). 

In addition, the electronic spectrum of uranyl superphthalocyanine 160 is significantly different from those of known metal phthalocyanine complexes... 

Fig. 8. Electronic spectrum of bacteriochlorophyll a (—) extracted from antenna complexes of purple bacteria compared to the spectrum of a synthetic phthalocyanine metal complex (—). Reproduced with permission from Ref (5). Copyright Wiley-VCH.

Ag1. A silver1 salt of TPP containing two silver atoms has been described it produces an electronic spectrum like that of the porphyrin dianions [Rothemund (153)]. Ag2I phthalocyanine is photolabile [Lever (122)]. 

Uranyl phthalocyanine 31) has a linear 0—U—O bond system whose asymmetric stretching frequency occurs at 920 cm-1. A band observed at 278 cm-1 in the far infrared is assigned to the 0—U—O bending vibration. The electronic spectrum of uranyl phthalocyanine in 1-chloronaphthalene is unique in having no absorption in the 500-800 mju region. All other phthalocyanines exhibit bands in this region (see Section V,B). The complex may be purified by sublimation, but is demetallated in sulfuric acid. 

The electronic spectrum in DMF solution had absorption bands at 634 and 660 nm. The polymer contained 4.0 mol% Fe(III)-Pc rings that were covalently bonded to polystyrene. If the amount of Fe(III)-Pc attached to the polymer was less than 4 mol%, the polymer was soluble in DMF or benzene. A Fe(III)-Pc-containing film was obtained by casting from a benzene solution. Co(II), Ni(II), and Cu(II)-phthalocyanine were bonded covalently to polystyrene in a similar way. 

The kinetic spectrum of chlorophyll a is quite different from that of the phthalocyanines (Fig. 17). There is only one maximum of slow electrons (0.3-0.5 e.v.), which widens as the photon energy is increased. 

Scandium phthalocyanine (H2pc) complexes have been obtained and quantum mechanical calculations carried out on these systems. Thus Sc(pc)Cl is obtained from reaction of ScCl3 with either phthalonitrile or with Li2(pc) and gives a molecular ion in the mass spectrum.29 The molecular orbitals of scandium (and other) phthalocyanines have been calculated and the electron distribution over the ring system studied in relation to the effect of the scandium ion.30... 

For the TOF SIMS analysis, only slides treated with a natural pH HAPS solution were used. These were subsequently extracted with warm and hot water. They were mounted into a grid sample holder for transportation into a VG IX23S time-of-flight (TOF) SIMS instrument operating at a vacuum of < 10 Torr with a microfocused liquid Ga metal ion primary beam source (30 keVx 1.0 nA). For charge compensation, an electron flood gun was used. The working resolution of the spectrometer was determined from a lead phthalocyanine spectrum for Pb+ at mlz = 208 and the molecular ion at mlz = 720, it was 500 and 1000, respectively. 

Perylenediimides represent another class of photoactive dyes which are characterized by their strong fluorescence emission and facile electrochemical reduction. Recently, a supramolecular bis(phthalocyanine)-perylenediimide hetero-triad (compound 42) has been assembled through axial coordination [47]. Treatment of perylenediimide 43, which has two 4-pyridyl substituents at the imido positions, with 2.5 equiv. of ruthenium(II) phthalocyanine 44 in chloroform affords 42 in 68% yield (Scheme 3). This array shows remarkable stability in solution due to the robustness of the ruthenium-pyridyl bond. Its electronic absorption spectrum is essentially the sum of the spectra of its molecular components 43 and 44 in... 

Oxidation of dilithium phthalocyanine Li2Pc affords a mono-lithium Pc rr-radical, LiPc, in which one unpaired electron resided in HOMO aiu n-orbital [23-25], ESR spectrum in chloronaphthalene solution was reported by Simon et al. [26], LiPc... 

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