Phthalocyanines spectra

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. 

The purity and the depth of the color of phthalocyanines arise front an isolated band (Q band) in the far-red end of the visible spectrum of light near 670 nm, with a molar absorption often exceeding 10s cm2 mol-1.77 321 A second absorption (B band), near 340 nm, extending to the blue of the visible spectrum is generally much less intense. Absorption spectra of 1,4-oc-tahcxyl-substitutcd PcNi322 and 1,4-octahexyl-substituted PcH2,323 both dissolved in chloroform, are shown below. 

The photochemical formation and the analysis of the absorption and magnetic circular dichro-ism spectra of the anion radical of zinc phthalocyanine were carried out. A complete assignment of the optical spectrum of the anion radical was proposed.834 Similarly, spectroelectrochemical cells have been used to record absorption and magnetic circular dichroism spectra of zinc phthalocyanines and a band assignment scheme proposed.835... 

The first, and still the most commonly used, of the tunable lasers were those based upon solutions of organic dyes. The first dye laser was developed by Sorokin and Lankard 05), and used a "chloro-aluminum phthalocyanine" (sic) solution. Tunable dye lasers operating throughout the visible spectrum were soon produced, using dyes such as coumarins, fluorescein, rhodamines, etc. Each dye will emit laser radiation which is continuously tunable over approximately the fluorescence wavelength range of the dye. 

The dithionite reduction of the micelle encapsulated aqua (hydroxo) ferric hemes at pH 10 (in inert atmosphere) gives an iron (II) porphyrin complex whose optical spectrum [21] shows two well-defined visible bands at 524 and 567 nm and a Soret band split into four bands (Fig. 10). Such spectral features are typical of four-coordinate iron (II) porphyrins. The magnetic moment (p = 3.8 + 0.2 Pb) of this sample in the micellar solution is also typical of intermediate spin iron(II) system and is similar to that reported for four-coordinate S = 1 iron(II) porphyrins and phthalocyanine [54-56]. The large orbital-contribution (ps.o. = 2.83 p for S = 1) observed in this iron(II) porphyrin... 

In systems in which the charge-transfer excitation band differs from the action spectrum of photoconductivity, the doping effect may be due to a change of recombination path that results in an enhancement of carrier liefetime (e.g. holes in merocyanines and phthalocyanines). (Details on the mechanism are given in 10,11,74).)... 

The photoconductivity of organic dyes, especially phthalocyanine pigments, could be utilized to provide reusable or non-reusable electrophotographic plates having sensitivities that extend over the entire visible spectrum and produce high-contrast images 167,168) Microcrystalline dispersions of metal-free phthalocyanine in suitable binders have a white-light sensitivity equal to that of selenium 169> and can be incorporated into coated papers and drums. 

LB films of 1,4,8,11,15,18-liexaoctyl-22,25-bis-(carboxypropyl)-phthalocyanine (2), an asymmetrically substituted phthalocyanine, were stable monolayers formed at the water—air interface that could be transferred onto hydrophilic silica substrates (32—34). When a monolayer film of the phthalocyanine derivative was heated, there was a remarkable change in the optical spectrum. This, by comparison to the spectrum of the bulk material, indicated a phase transition from the low temperature herringbone packing, to a high temperature hexagonal packing. 

Porphyrin [125-128] and phthalocyanine [129] derivatives are also employed as photosensitizers in DSSCs. A nanocrystalline Ti02 solar cell sensitized by Cu chlorophyllin produced 2.6% efficiency (./ . = 9.4 mA/cm2 and Voc = 0.52 V) under 100 mW/cm2 [127]. In order to develop new, efficient, metal dye photosensitizers, both an increase in the absorption coefficient of the metal complex and a greater red shift of the absorption spectrum is required. 

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. 

Solid /8-CrPc reacts reversibly with gaseous NO at ambient temperature to give a 1 1 adduct, which reacts with both py and 02 (Scheme 117).596 No structural information is available on the oxidation product of the nitrosyl complex. In contrast to the /3 form, solid ar-CrPc is unreactive towards either 02 or NO, a difference ascribed to the solid-state structures of the two polymorphs.597 Although the distance between the phthalocyanine planes is similar (340 pm), in both cases the metal-metal distance increases from 340 to 480 pm on going from the a to the /3 form. These distances are sufficient to permit access of 02 or NO in the /8 form, while excluding them from the a form. The addition of py to CrPc(NO) causes the NO stretching band in the IR spectrum to intensify and to sharpen considerably. The diffuse nature of this band in CrPc(NO) indicates the presence of a perturbed NO ligand but the introduction of py causes lattice expansion and eliminates the perturbation. 

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... 

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