- Photoinduced electron transfer of double-bridged phthalocyanine-fullerene dyads
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Three new double-bridged phthalocyanine-fullerene dyads were studied with spectroscopic and electrochemical methods. The two-linker strategy was applied for the first time to phthalocyanine-fullerene dyads. Photoinduced electron transfer (ET) of the dyads was found to occur from the excited state of phthalocyanine both in polar and non-polar environment. Examination of ET energetics revealed that the phthalocyanine-fullerene dyads exist mainly in an extended conformation as opposed to a face-to-face orientation common for the similar double-bridged porphyrin-fullerene dyads.
- Isosomppi, Marja,Tkachenko, Nikolai V.,Efimov, Alexander,Vahasalo, Heidi,Jukola, Johanna,Vainiotalo, Pirjo,Lemmetyinen, Helge
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- Effect of non-peripheral alkyloxy substituents on the structure and spectroscopic properties of metal-free phthalocyanines
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Four non-peripheral alkyloxy substituted metal-free phthalocyanines have been synthesized and characterized with X-ray crystal structure, IR, UV-vis and 1H NMR. It is found that the center caves of Pc skeletons were expanded but their ring currents were reduced by the introduction of alkyloxy substituents on the non-peripheral positions.
- Lin, Mei-Jin,Wang, Jun-Dong
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- α-Substituted Bis(octabutoxyphthalocyaninato)Terbium(III) Double-Decker Complexes: Preparation and Study of Protonation by NMR and DFT
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Synthesis of the anionic, α-substituted, bis(phthalocyaninato)TbIII complex [Tb(α-obPc)2]- ([1]-) (obPc = α-octabutoxyphthalocyaninato) leads to the isolation of its protonated form [1H]0. This complex was characterized by X-ray diffraction (XRD), mass spectroscopy (MS), infrared (IR) and ultraviolet-visible-near-infrared (UV-vis-NIR) spectroscopy. Crystal structure analysis did not allow localization of the additional proton, which is probably attached to the meso-N atom or isoindole-N atom of the phthalocyaninato ligand. [1H]0 can easily be deprotonated or protonated, giving the corresponding anionic and cationic complexes. The three compounds [1H]0, [1]-, and [1HH]+ were studied by a combination of paramagnetic NMR experiments (1H, 13C, variable-temperature measurements, two-dimensional nuclear magnetic resonance and DFT calculations (done on YIII analogues with octamethoxyphthalocyaninato ligands), for the purpose of elucidating the positions of the acidic protons and for understanding the structural changes of the coordination environment of the Tb ion induced by protonation.
- Damjanovi?, Marko,Horie, Yusuke,Morita, Takaumi,Horii, Yoji,Katoh, Keiichi,Yamashita, Masahiro,Enders, Markus
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- Temperature-dependent changes in the molecular orientation and visible color of phthalocyanine films
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A simple phthalocyanine zinc complex exhibits a visible color change in response to weak external stimuli, i.e., changes in solvent and temperature. Its chromism was attributed to its controlled aggregation via weak interactions between the central metal and peripheral oxygen atoms. In solution, intense absorption and fluorescence bands appeared in both the longer-wavelength and NIR region in non-coordinating solvents, while a simple sharp Q band was observed in coordinating solvents. Variable-temperature absorption spectra and fluorescence lifetime measurements were used to characterize the aggregation-induced absorption and emission in non-coordinating solvents. A selective aggregation-disaggregation process was also observed in thin films of this phthalocyanine zinc complex, and the optical properties of the film depend on the annealing temperature. The changes in the NIR region lead to a sizable visible color change that is recognizable by the naked human eye. The temperature-dependent control of the aggregation process in the thin film was confirmed using operando spectroscopy techniques. This journal is
- Chikamatsu, Tatsuki,Furuyama, Taniyuki,Horikawa, Takafumi,Maeda, Hajime,Segi, Masahito,Taima, Tetsuya,Takahashi, Hiromi,Uchiyama, Shiori
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p. 31348 - 31354
(2020/09/21)
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- Facile tuning of strong near-IR absorption wavelengths in manganese(iii) phthalocyanines: Via axial ligand exchange
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The facile tuning of near-infrared absorption of manganese(iii) phthalocyanines was accomplished by changing the nature and number of bound axial ligands. For a series of axial ligands on manganese α-octabutoxyphthalocyanine and α-octakis-(isopropylthio)phthalocyanine, the electron density on the metal and its displacement from the Pc-ring plane both control the position of the complex's Q-band. For these two macrocycles, this strong absorption band could be tuned over a λmax range of 815-948 nm by axial ligand exchange.
- McKearney, Declan,Zhou, Wen,Zellman, Carson,Williams, Vance E.,Leznoff, Daniel B.
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supporting information
p. 6696 - 6699
(2019/06/17)
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- Changes of phthalocyanine visible color caused by near-IR solvatochromism
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Herein, we show that the Zn complex of 1,4,8,11,15,18,22,28-octakis(butoxy)phthalocyanine exhibits solvatochromism and characterize the corresponding visible color changes. In particular, we reveal that although the variation of the solvent-dependent position of the Q band is relatively small (～100 nm), the solution colors change from red to yellow and green depending on the composition of the solvent mixture. Moreover, the above Q band was located at the border between the visible and near-IR regions, i.e. its red shift could not be directly recognized by the human naked eye. Substituents on oxygen atoms were shown to influence phthalocyanine aggregation and thus affect near-IR absorption, with the observed near-IR solvatochromism providing a new strategy of color change in response to weak external stimuli.
- Furuyama, Taniyuki,Uchiyama, Shiori,Iwamoto, Takayuki,Maeda, Hajime,Segi, Masahito
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- Photoinduced vectorial electron transfer in multilayered Langmuir-Blodgett films of porphyrin and phtalocyanine derivatives
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A series of new phtalocyanines and phtalocyanine-fullerene dyads was synthesized. The dyads were transferred to solid substrates in the form of the Langmuir-Blodgett films. Poly(hexylthiophene) (PHT) and/or phtalocyanine (B6PH) were used as secondary electron donors in the multilayered structures, together with molecules of phtalocyanine-fullerene (B6PF) or porphyrin-fullerene (DHD6ee) dyads in a matrix of octadecylamine (ODA) molecules in a ratio of 1: 9. Directed photoinduced electron transfer in films was studied by means of the time-resolved Maxwell displacement charge method. It was established that the addition of a monolayer of molecules of the secondary B6PH donor to a monolayer of molecules of the DHD6ee/ODA (1: 9) dyad resulted in a thirty-fold increase in the sample's photovoltaic response; it did not, however, change the recombination rate of the charges as compared to a single monolayer of the dyad molecules. In the case of bilayer samples consisting of B6PF/ODA (1: 9) and PHT/ODA (3: 2) monolayers, both quantities increased. The absorption of visible light over a wide spectral range was achieved via the use of three-component (PHT, B6PH and DHD6ee) multilayered structures. The relative sensitivities of the samples to excitation radiation were assessed and the efficiencies of their transformation of light energy to electric potential were compared. The largest sensitivity values were obtained for three-component samples prepared from PHT, B6PH, and DHD6ee monolayers in which the sensitivity value was 500 times larger than that for a separate monolayer of DHD6ee dyad molecules.
- Alekseev,Tkachenko,Efimov,Lemmetyinen
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experimental part
p. 1230 - 1241
(2011/01/05)
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- Synthesis of a series of octabutoxy- and octabutoxybenzophthalocyanines and photophysical properties of two members of the series
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We have developed a new route to silicon-centered phthalocyanines and phthalocyanine-like compounds that is robust and flexible, and of considerable potential usefulness. This route entails insertion of silicon into the metal-free macrocycle. It has been developed in the course of preparing four new and two known metal-free, six new dihydroxysilicon, and six new bis-trihexylsiloxysilicon octabutoxy- and octabutoxybenzophthalocyanines. One of the siloxysilicon compounds, that with the ligand 5,9,12,16,19,23,28,32-octabutoxy-33H,35H- dibenzo[b,g]dinaphtho[2,3-1:2',3'-q]porphyrazine, has a Q-band at a wavelength of 804 nm and an extinction coefficient of 1.9 x 105 M-1 cm- 1. Its wavelength thus matches the wavelength of the output of the most common GaA1As diode laser. The compound and its analog in which the benzo rings are trans to each other instead of cis have no tendency to aggregate in benzene up to a concentration of 150 μM. The triplet state of the cis isomer has an absorption maximum at 640 nm and a lifetime in deaerated benzene solution of 105 μs, while the triplet state of the trans isomer has a maximum at 660 nm and a lifetime of 72 μs. Both isomers have a triplet quantum yield, Q1, of ca. 0.20 and a singlet oxygen quantum yield, Q(Δ), of ca, 0.20, photochemical properties that are consistent with potentially efficient photosensitization action in photodynamic therapy of tumors. For both sensitizers, energy transfer from the sensitizer triplet to ground state of dioxygen is reversible at appropriate concentrations. For the cis isomer, the equilibrium constant for the energy transfer process, K(e), is 0.012 ± 0.001, and the triplet state energy calculated from this, E(T), is 21.29 kcal/mol (E(T) derived from phosphorescence measurements is 21.26 kcal/mol). For the trans isomer, K(e) is 3.68 x 10-3 and E(T) is 19.27 kcal/mol.
- Aoudia, Mohamed,Cheng, Gongzhen,Kennedy, Vance O.,Kenney, Malcolm E.,Rodgers, Michael A. J.
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p. 6029 - 6039
(2007/10/03)
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- Synthesis and photoproperties of diamagnetic octabutoxyphthalocyanines with deep red optical absorbance
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The synthesis and photoproperties of six new metal 1,4,8,11,15,18,22,25-octabutoxyphthalocyanines and photoproperties of the known analogous Zn and metal-free phthalocyanines are described. The new compounds are AIPc(OBu)8OSiEt3, GaPc(OBu)8OSiEt3, GePc(OBu)8(OSiEt3)2, SnPc(OBu)8(OSiEt3)2, RuPc(OBu)8(py)2, and PdPc(OBu)8 (where Pc(OBu)8 represents the octabutoxyphthalocyanine ligand). Benzene-d6 solutions of all eight of the compounds give NMR spectra showing large ring-current effects. Benzene solutions of the compounds give visible spectra with absorption maxima in the 688-779-nm range having extinction coefficients between 1.0 × 105 and 2.2 × 105 M-1cm-1. The triplet-state properties of the phthalocyanines in benzene solutions have been measured by laser flash photolysis. The triplet states have absorption maxima in the 550-640-nm range, quantum yields in the 0.1-0.9 range, and lifetime when the solutions are deaerated in the 0.5-150-μs range. The rate constants for energy transfer from the triplet states of the compounds to O2 are between 1.3 × 108 and 2.8 × 109 M-1 s-1. Analysis of kinetic data pertaining to the photogeneration of O2 (1Δg) by the main-group compounds shows that the energy gap between their singlet (S1) and triplet (T1) states is 14.9 ± 0.3 kcal/mol. Relationships between the photoproperties of the metal complexes and the position in the periodic chart of the metals they contain are apparent.
- Rihter, Boris D.,Kenney, Malcolm E.,Ford, William E.,Rodgers, Michael A. J.
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p. 8064 - 8070
(2007/10/02)
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- Octa-alkoxy Phthalocyanine and Naphthalocyanine Derivatives: Dyes with Q-band Absorption in the Far Red or Near Infrared
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The lithium alkoxide-catalysed cyclic tetramerisation of various 3,6-dialkoxy-4,5-dichlorophthalonitriles, 1,4-dialkoxynaphthalene-2,3-dicarbonitriles and 3,6-dialkoxyphthalonitriles to give the corresponding metal-free octa-alkoxyoctachlorophthalocyanines, octa-alkoxynaphthalocyanines and octa-alkoxyphthalocyanines is described.An unexpected trans-alkoxylation reaction occurs during the cyclisation of the first two series of precursors.Metal-free phthalocyanines and naphthalocyanines have been converted into derivatives containing various metal ions.Compounds show Q-band absorption in the region 739-862 nm in toluene solution.The fluorescence spectra of selected examples are reported.The solubility of some of the compounds has been measured in a formulation of liquid crystal materials.
- Cook, Michael J.,Dunn, Adrian J.,Howe, Steven D.,Thomson, Andrew J.,Harrison, Kenneth J.
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p. 2453 - 2458
(2007/10/02)
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