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15 pages, 12057 KiB

Open AccessArticle

N-Confused Porphyrin Immobilized on Solid Supports: Synthesis and Metal Ions Sensing Efficacy

by Sara R. D. Gamelas, Ana T. P. C. Gomes, Nuno M. M. Moura, Maria A. F. Faustino, José A. S. Cavaleiro, Carlos Lodeiro, Marta I. S. Veríssimo, Tiago Fernandes, Ana L. Daniel-da-Silva, M. Teresa S. R. Gomes and Maria G. P. M. S. Neves

Molecules 2018, 23(4), 867; https://doi.org/10.3390/molecules23040867 - 10 Apr 2018

Cited by 19 | Viewed by 6432

Abstract

In this work, the N-confused porphyrin 5,10,15,20-tetraphenyl-2-aza-21-carbaporphyrin (NCTPP) was immobilized on neutral or cationic supports based on silica and on Merrifield resin. The new materials were characterized by appropriate techniques (UV-Vis spectroscopy, SEM, and zeta potential analysis). Piezoelectric quartz crystal gold electrodes [...] Read more.

In this work, the N-confused porphyrin 5,10,15,20-tetraphenyl-2-aza-21-carbaporphyrin (NCTPP) was immobilized on neutral or cationic supports based on silica and on Merrifield resin. The new materials were characterized by appropriate techniques (UV-Vis spectroscopy, SEM, and zeta potential analysis). Piezoelectric quartz crystal gold electrodes were coated with the different hybrids and their ability to interact with heavy metals was evaluated. The preliminary results obtained showed that the new materials can be explored for metal cations detection and the modification of the material surface is a key factor in tuning the metal selectivity. Full article

(This article belongs to the Special Issue Porphyrins and Phthalocyanines: Synthesis, Properties and Applications)

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1426 KiB

Open AccessCommunication

Unexpected Synthesis of a Bulky Bis-Pocket A₃B-Type Meso-Cyano Porphyrin

by Ze-Yu Liu, Mian HR Mahmood, Jian-Zhong Wu, Shu-Bao Yang and Hai-Yang Liu

Molecules 2017, 22(11), 1941; https://doi.org/10.3390/molecules22111941 - 9 Nov 2017

Cited by 6 | Viewed by 5375

Abstract

A one-pot synthesis of bulky bis-pocket A₃B-type meso-cyano porphyrin, 5-cyano-10,15,20-tris(2,4,6-triphenylphenyl)porphyrin, has been accomplished via trifluoroacetic acid (TFA) catalyzed condensation of pyrrole and 2,4,6-triphenylbenzaldehyde in an acceptable yield of about 4%. DDQ served as oxidant and the cyanating agent. Full article

(This article belongs to the Special Issue Porphyrins and Phthalocyanines: Synthesis, Properties and Applications)

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3986 KiB

Open AccessArticle

Ultrafast Dynamics of Sb-Corroles: A Combined Vis-Pump Supercontinuum Probe and Broadband Fluorescence Up-Conversion Study

by Clark Zahn, Till Stensitzki, Mario Gerecke, Alexander Berg, Atif Mahammed, Zeev Gross and Karsten Heyne

Molecules 2017, 22(7), 1174; https://doi.org/10.3390/molecules22071174 - 13 Jul 2017

Cited by 19 | Viewed by 6026

Abstract

Corroles are a developing class of tetrapyrrole-based molecules with significant chemical potential and relatively unexplored photophysical properties. We combined femtosecond broadband fluorescence up-conversion and fs broadband Vis-pump Vis-probe spectroscopy to comprehensively characterize the photoreaction of 5,10,15-tris-pentafluorophenyl-corrolato-antimony(V)-trans-difluoride (Sb-tpfc-F₂). Upon fs [...] Read more.

Corroles are a developing class of tetrapyrrole-based molecules with significant chemical potential and relatively unexplored photophysical properties. We combined femtosecond broadband fluorescence up-conversion and fs broadband Vis-pump Vis-probe spectroscopy to comprehensively characterize the photoreaction of 5,10,15-tris-pentafluorophenyl-corrolato-antimony(V)-trans-difluoride (Sb-tpfc-F₂). Upon fs Soret band excitation at ~400 nm, the energy relaxed almost completely to Q band electronic excited states with a time constant of 500 ± 100 fs; this is evident from the decay of Soret band fluorescence at around 430 nm and the rise time of Q band fluorescence, as well as from Q band stimulated emission signals at 600 and 650 nm with the same time constant. Relaxation processes on a time scale of 10 and 20 ps were observed in the fluorescence and absorption signals. Triplet formation showed a time constant of 400 ps, with an intersystem crossing yield from the Q band to the triplet manifold of between 95% and 99%. This efficient triplet formation is due to the spin-orbit coupling of the antimony ion. Full article

(This article belongs to the Special Issue Porphyrins and Phthalocyanines: Synthesis, Properties and Applications)

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2151 KiB

Open AccessArticle

Efficiency of Dinucleosides as the Backbone to Pre-Organize Multi-Porphyrins and Enhance Their Stability as Sandwich Type Complexes with DABCO

by Sonja Merkaš, Souhaila Bouatra, Régis Rein, Ivo Piantanida, Mladen Zinic and Nathalie Solladié

Molecules 2017, 22(7), 1112; https://doi.org/10.3390/molecules22071112 - 6 Jul 2017

Cited by 3 | Viewed by 4869

Abstract

Flexible linkers such as uridine or 2′-deoxyuridine pre-organize bis-porphyrins in a face-to-face conformation, thus forming stable sandwich complexes with a bidentate base such as 1,4-diazabicyclo[2.2.2]octane (DABCO). Increased stability can be even greater when a dinucleotide linker is used. Such pre-organization increases the association [...] Read more.

Flexible linkers such as uridine or 2′-deoxyuridine pre-organize bis-porphyrins in a face-to-face conformation, thus forming stable sandwich complexes with a bidentate base such as 1,4-diazabicyclo[2.2.2]octane (DABCO). Increased stability can be even greater when a dinucleotide linker is used. Such pre-organization increases the association constant by one to two orders of magnitude when compared to the association constant of DABCO with a reference porphyrin. Comparison with rigid tweezers shows a better efficiency of nucleosidic dimers. Thus, the choice of rigid spacers is not the only way to pre-organize bis-porphyrins, and well-chosen nucleosidic linkers offer an interesting option for the synthesis of such devices. Full article

(This article belongs to the Special Issue Porphyrins and Phthalocyanines: Synthesis, Properties and Applications)

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1870 KiB

Open AccessArticle

Molecular Orientation of a Terbium(III)-Phthalocyaninato Double-Decker Complex for Effective Suppression of Quantum Tunneling of the Magnetization

by Tsutomu Yamabayashi, Keiichi Katoh, Brian K. Breedlove and Masahiro Yamashita

Molecules 2017, 22(6), 999; https://doi.org/10.3390/molecules22060999 - 15 Jun 2017

Cited by 31 | Viewed by 5847

Abstract

Single-molecule magnet (SMM) properties of crystals of a terbium(III)-phthalocyaninato double-decker complex with different molecular packings (1: TbPc₂, 2: TbPc₂·CH₂Cl₂) were studied to elucidate the relationship between the molecular packing and SMM properties. [...] Read more.

Single-molecule magnet (SMM) properties of crystals of a terbium(III)-phthalocyaninato double-decker complex with different molecular packings (1: TbPc₂, 2: TbPc₂·CH₂Cl₂) were studied to elucidate the relationship between the molecular packing and SMM properties. From single crystal X-ray analyses, the high symmetry of the coordination environment of 2 suggested that the SMM properties were improved. Furthermore, the shorter intermolecular Tb–Tb distance and relative collinear alignment of the magnetic dipole in 2 indicated that the magnetic dipole–dipole interactions were stronger than those in 1. This was confirmed by using direct current magnetic measurements. From alternating current magnetic measurements, the activation energy for spin reversal for 1 and 2 were similar. However, the relaxation time for 2 is three orders of magnitude slower than that for 1 in the low-T region due to effective suppression of the quantum tunneling of the magnetization. These results suggest that the SMM properties of TbPc₂ highly depend on the molecular packing. Full article

(This article belongs to the Special Issue Porphyrins and Phthalocyanines: Synthesis, Properties and Applications)

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3545 KiB

Open AccessArticle

Synthesis, Characterization and Protonation Behavior of Quinoxaline-Fused Porphycenes

by Daiki Kuzuhara, Mika Sakaguchi, Wataru Furukawa, Takuya Okabe, Naoki Aratani and Hiroko Yamada

Molecules 2017, 22(6), 908; https://doi.org/10.3390/molecules22060908 - 31 May 2017

Cited by 14 | Viewed by 5940

Abstract

9,10-Quinoxaline-fused porphycenes 1a-H₂ and 1b-H₂ were synthesized by intramolecular McMurry coupling. As a result of the annulation of the quinoxaline moiety on the porphycene skeleton, 1a-H₂ and 1b-H₂ display absorption and fluorescence in the near infra-red (NIR) region. Additionally, [...] Read more.

9,10-Quinoxaline-fused porphycenes 1a-H₂ and 1b-H₂ were synthesized by intramolecular McMurry coupling. As a result of the annulation of the quinoxaline moiety on the porphycene skeleton, 1a-H₂ and 1b-H₂ display absorption and fluorescence in the near infra-red (NIR) region. Additionally, the quinoxaline moieties of 1a-H₂ and 1b-H₂ act as electron-withdrawing groups, introducing lower reduction potentials than for pristine porphycene. The protonation occurred at the nitrogen atoms in the cavity of freebase porphycenes and at the quinoxaline moieties for their nickel complexes to give diprotonic species. Full article

(This article belongs to the Special Issue Porphyrins and Phthalocyanines: Synthesis, Properties and Applications)

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Open AccessArticle

Preparation and In Vitro Photodynamic Activity of Glucosylated Zinc(II) Phthalocyanines as Underlying Targeting Photosensitizers

by Jian-Yong Liu, Chen Wang, Chun-Hui Zhu, Zhi-Hong Zhang and Jin-Ping Xue

Molecules 2017, 22(5), 845; https://doi.org/10.3390/molecules22050845 - 19 May 2017

Cited by 15 | Viewed by 5427

Abstract

Two novel glucosylated zinc(ІІ) phthalocyanines 7a–7b, as well as the acetyl-protected counterparts 6a–6b, have been synthesized by the Cu(I)-catalyzed 1,3-dipolar cycloaddition between the propargylated phthalocyanine and azide-substituted glucoses. All of these phthalocyanines were characterized with various spectroscopic methods and studied for their photo-physical, [...] Read more.

Two novel glucosylated zinc(ІІ) phthalocyanines 7a–7b, as well as the acetyl-protected counterparts 6a–6b, have been synthesized by the Cu(I)-catalyzed 1,3-dipolar cycloaddition between the propargylated phthalocyanine and azide-substituted glucoses. All of these phthalocyanines were characterized with various spectroscopic methods and studied for their photo-physical, photo-chemical, and photo-biological properties. With glucose as the targeting unit, phthalocyanines 7a–7b exhibit a specific affinity to MCF-7 breast cancer cells over human embryonic lung fibroblast (HELF) cells, showing higher cellular uptake. Upon illumination, both photosensitizers show high cytotoxicity with IC₅₀ as low as 0.032 µM toward MCF-7 cells, which are attributed to their high cellular uptake and low aggregation tendency in the biological media, promoting the generation of intracellular reactive oxygen species (ROS). Confocal laser fluorescence microscopic studies have also revealed that they have high and selective affinities to the lysosomes, but not the mitochondria, of MCF-7 cells. The results show that these two glucosylated zinc(II) phthalocyanines are potential anticancer agents for targeting photodynamic therapy. Full article

(This article belongs to the Special Issue Porphyrins and Phthalocyanines: Synthesis, Properties and Applications)

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2391 KiB

Open AccessArticle

Modes of Cell Death Induced by Photodynamic Therapy Using Zinc Phthalocyanine in Lung Cancer Cells Grown as a Monolayer and Three-Dimensional Multicellular Spheroids

by Sello L. Manoto, Nicolette Houreld, Natasha Hodgkinson and Heidi Abrahamse

Molecules 2017, 22(5), 791; https://doi.org/10.3390/molecules22050791 - 16 May 2017

Cited by 12 | Viewed by 7574

Abstract

Photodynamic therapy (PDT) involves interaction of a photosensitizer, light, and molecular oxygen which produces singlet oxygen and subsequent tumour eradication. The development of second generation photosensitizers, such as phthalocyanines, has improved this technology. Customary monolayer cell culture techniques are, unfortunately, too simple to [...] Read more.

Photodynamic therapy (PDT) involves interaction of a photosensitizer, light, and molecular oxygen which produces singlet oxygen and subsequent tumour eradication. The development of second generation photosensitizers, such as phthalocyanines, has improved this technology. Customary monolayer cell culture techniques are, unfortunately, too simple to replicate treatment effects in vivo. Multicellular tumour spheroids may provide a better alternative since they mimic aspects of the human tumour environment. This study aimed to profile 84 genes involved in apoptosis following treatment with PDT on lung cancer cells (A549) grown in a monolayer versus three-dimensional multicellular tumour spheroids (250 and 500 μm). Gene expression profiling was performed 24 h post irradiation (680 nm; 5 J/cm²) with zinc sulfophthalocyanine (ZnPcS_mix) to determine the genes involved in apoptotic cell death. In the monolayer cells, eight pro-apoptotic genes were upregulated, and two were downregulated. In the multicellular tumour spheroids (250 µm) there was upregulation of only 1 gene while there was downregulation of 56 genes. Apoptosis in the monolayer cultured cells was induced via both the intrinsic and extrinsic apoptotic pathways. However, in the multicellular tumour spheroids (250 and 500 µm) the apoptotic pathway that was followed was not conclusive. Full article

(This article belongs to the Special Issue Porphyrins and Phthalocyanines: Synthesis, Properties and Applications)

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723 KiB

Open AccessArticle

A Cost-Efficient Method for Unsymmetrical Meso-Aryl Porphyrin Synthesis Using NaY Zeolite as an Inorganic Acid Catalyst

by Mário J. F. Calvete, Lucas D. Dias, César A. Henriques, Sara M. A. Pinto, Rui M. B. Carrilho and Mariette M. Pereira

Molecules 2017, 22(5), 741; https://doi.org/10.3390/molecules22050741 - 5 May 2017

Cited by 18 | Viewed by 6358

Abstract

Herein we report the synthesis of unsymmetrical meso-aryl substituted porphyrins, using NaY zeolite as an inorganic acid catalyst. A comparative study between this method and the several synthetic strategies available in the literature was carried out. Our method presented a better, more [...] Read more.

Herein we report the synthesis of unsymmetrical meso-aryl substituted porphyrins, using NaY zeolite as an inorganic acid catalyst. A comparative study between this method and the several synthetic strategies available in the literature was carried out. Our method presented a better, more cost-efficient rationale and displayed a significantly lower environmental impact. Furthermore, it was possible to verify the scalability of the process as well as the reutilization of the inorganic catalyst NaY (up to 6 times) without significant yield decrease. In addition, this method was applied to the synthesis of several other unsymmetrical porphyrins, from a low melting point porphyrin to mono-carboxylated halogenated unsymmetrical porphyrins, in yields higher than those found in the literature. Additionally, for the first time, two acetamide functionalized halogenated porphyrins were prepared in high yields. This methodology opens the way to the preparation of high yielding functionalized porphyrins, which can be easily immobilized for a variety of applications, either in catalysis or in biomedicine. Full article

(This article belongs to the Special Issue Porphyrins and Phthalocyanines: Synthesis, Properties and Applications)

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2298 KiB

Open AccessArticle

Off-Center Rotation of CuPc Molecular Rotor on a Bi(111) Surface and the Chiral Feature

by Kai Sun, Min-Long Tao, Yu-Bing Tu and Jun-Zhong Wang

Molecules 2017, 22(5), 740; https://doi.org/10.3390/molecules22050740 - 4 May 2017

Cited by 8 | Viewed by 5460

Abstract

Molecular rotors with an off-center axis and the chiral feature of achiral CuPc molecules on a semi-metallic Bi(111) surface have been investigated by means of a scanning tunneling microscopy (STM) at liquid nitrogen (LN₂) temperature. The rotation axis of each CuPc [...] Read more.

Molecular rotors with an off-center axis and the chiral feature of achiral CuPc molecules on a semi-metallic Bi(111) surface have been investigated by means of a scanning tunneling microscopy (STM) at liquid nitrogen (LN₂) temperature. The rotation axis of each CuPc molecular rotor is located at the end of a phthalocyanine group. As molecular coverage increases, the CuPc molecules are self-assembled into various nanoclusters and finally into two-dimensional (2D) domains, in which each CuPc molecule exhibits an apparent chiral feature. Such chiral features of the CuPc molecules can be attributed to the combined effect of asymmetric charge transfer between the CuPc and Bi(111) substrate, and the intermolecular van der Waals interactions. Full article

(This article belongs to the Special Issue Porphyrins and Phthalocyanines: Synthesis, Properties and Applications)

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1369 KiB

Open AccessArticle

Template Effect of the Graphene Moiré Lattice on Phthalocyanine Assembly

by Nicolas Néel and Jörg Kröger

Molecules 2017, 22(5), 731; https://doi.org/10.3390/molecules22050731 - 3 May 2017

Cited by 7 | Viewed by 7307

Abstract

Superstructures of metal-free phthalocyanine (2H-Pc) molecules on graphene-covered Ir(111) have been explored by scanning tunnelling microscopy. Depending on the sub-monolayer coverage different molecular assemblies form at the surface. They reflect the transition from a graphene template effect on the 2H-Pc arrangement to molecular [...] Read more.

Superstructures of metal-free phthalocyanine (2H-Pc) molecules on graphene-covered Ir(111) have been explored by scanning tunnelling microscopy. Depending on the sub-monolayer coverage different molecular assemblies form at the surface. They reflect the transition from a graphene template effect on the 2H-Pc arrangement to molecular superstructures that are mainly governed by the intermolecular coupling. Full article

(This article belongs to the Special Issue Porphyrins and Phthalocyanines: Synthesis, Properties and Applications)

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4276 KiB

Open AccessArticle

Synthesis and Spectral Properties of meso-Arylbacteriochlorins, Including Insights into Essential Motifs of their Hydrodipyrrin Precursors

by Muthyala Nagarjuna Reddy, Shaofei Zhang, Han-Je Kim, Olga Mass, Masahiko Taniguchi and Jonathan S. Lindsey

Molecules 2017, 22(4), 634; https://doi.org/10.3390/molecules22040634 - 14 Apr 2017

Cited by 7 | Viewed by 5485

Abstract

Synthetic bacteriochlorins—analogues of bacteriochlorophylls, Nature’s near-infrared absorbers—are attractive for diverse photochemical studies. meso-Arylbacteriochlorins have been prepared by the self-condensation of a dihydrodipyrrin–carbinol or dihydrodipyrrin–acetal following an Eastern-Western (E-W) or Northern-Southern (N-S) joining process. The bacteriochlorins bear a gem-dimethyl group in each pyrroline [...] Read more.

Synthetic bacteriochlorins—analogues of bacteriochlorophylls, Nature’s near-infrared absorbers—are attractive for diverse photochemical studies. meso-Arylbacteriochlorins have been prepared by the self-condensation of a dihydrodipyrrin–carbinol or dihydrodipyrrin–acetal following an Eastern-Western (E-W) or Northern-Southern (N-S) joining process. The bacteriochlorins bear a gem-dimethyl group in each pyrroline ring to ensure stability toward oxidation. The two routes differ in the location of the gem-dimethyl group at the respective 3- or 2-position in the dihydrodipyrrin, and the method of synthesis of the dihydrodipyrrin. Treatment of a known 3,3-dimethyldihydrodipyrrin-1-carboxaldehyde with an aryl Grignard reagent afforded the dihydrodipyrrin-1-(aryl)carbinol, and upon subsequent acetylation, the corresponding dihydrodipyrrin-1-methyl acetate (dihydrodipyrrin–acetate). Self-condensation of the dihydrodipyrrin–acetate gave a meso-diarylbacteriochlorin (E-W route). A 2,2-dimethyl-5-aryldihydrodipyrrin-1-(aryl)carbinol underwent self-condensation to give a trans-A₂B₂-type meso-tetraarylbacteriochlorin (N-S route). In each case, the aromatization process entails a 2e⁻/2H⁺ (aerobic) dehydrogenative oxidation following the dihydrodipyrrin self-condensation. Comparison of a tetrahydrodipyrrin–acetal (0%) versus a dihydrodipyrrin–acetal (41%) in bacteriochlorin formation and results with various 1-substituted dihydrodipyrrins revealed the importance of resonance stabilization of the reactive hydrodipyrrin intermediate. Altogether 10 new dihydrodipyrrins and five new bacteriochlorins have been prepared. The bacteriochlorins exhibit characteristic bacteriochlorophyll-like absorption spectra, including a Q_y band in the region 726–743 nm. Full article

(This article belongs to the Special Issue Porphyrins and Phthalocyanines: Synthesis, Properties and Applications)

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1817 KiB

Open AccessArticle

Efficient Catalytic Oxidation of 3-Arylthio- and 3-Cyclohexylthio-lapachone Derivatives to New Sulfonyl Derivatives and Evaluation of Their Antibacterial Activities

by Mariana F. do C. Cardoso, Ana T. P. C. Gomes, Caroline Dos S. Moreira, Mário M. Q. Simões, Maria G. P. M. S. Neves, David R. Da Rocha, Fernando De C. Da Silva, Catarina Moreirinha, Adelaide Almeida, Vitor F. Ferreira and José A. S. Cavaleiro

Molecules 2017, 22(2), 302; https://doi.org/10.3390/molecules22020302 - 16 Feb 2017

Cited by 9 | Viewed by 5471

Abstract

New sulfonyl-lapachones were efficiently obtained through the catalytic oxidation of arylthio- and cyclohexylthio-lapachone derivatives with hydrogen peroxide in the presence of a Mn(III) porphyrin complex. The antibacterial activities of the non-oxidized and oxidized lapachone derivatives against the Gram-negative bacteria Escherichia coli and the [...] Read more.

New sulfonyl-lapachones were efficiently obtained through the catalytic oxidation of arylthio- and cyclohexylthio-lapachone derivatives with hydrogen peroxide in the presence of a Mn(III) porphyrin complex. The antibacterial activities of the non-oxidized and oxidized lapachone derivatives against the Gram-negative bacteria Escherichia coli and the Gram-positive bacteria Staphylococcus aureus were evaluated after their incorporation into polyvinylpyrrolidone (PVP) micelles. The obtained results show that the PVP-formulations of the lapachones 4b–g and of the sulfonyl-lapachones 7e and 7g reduced the growth of S. aureus. Full article

(This article belongs to the Special Issue Porphyrins and Phthalocyanines: Synthesis, Properties and Applications)

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Review

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Open AccessReview

Electronic Spectroscopy of Phthalocyanine and Porphyrin Derivatives in Superfluid Helium Nanodroplets

by Alkwin Slenczka

Molecules 2017, 22(8), 1244; https://doi.org/10.3390/molecules22081244 - 25 Jul 2017

Cited by 11 | Viewed by 5669

Abstract

Phthalocyanine and porphyrin were among the first organic compounds investigated by means of electronic spectroscopy in superfluid helium nanodroplets. Superfluid helium nanodroplets serve as a very gentle host system for preparing cold and isolated molecules. The uniqueness of helium nanodroplets is with respect [...] Read more.

Phthalocyanine and porphyrin were among the first organic compounds investigated by means of electronic spectroscopy in superfluid helium nanodroplets. Superfluid helium nanodroplets serve as a very gentle host system for preparing cold and isolated molecules. The uniqueness of helium nanodroplets is with respect to the superfluid phase which warrants the vanishing viscosity and, thus, minimal perturbation of the dopant species at a temperature as low as 0.37 K. These are ideal conditions for the study of molecular spectra in order to analyze structures as well as dynamic processes. Besides the investigation of the dopant species itself, molecular spectroscopy in helium droplets provides information on the helium droplet and in particular on microsolvation. This article, as part of a special issue on phthalocyanines and porphyrins, reviews electronic spectroscopy of phthalocyanine and porphyrin compounds in superfluid helium nanodroplets. In addition to the wide variety of medical as well as technical and synthetical aspects, this article discusses electronic spectroscopy of phthalocyanines and porphyrins in helium droplets in order to learn about both the dopant and the helium environment. Full article

(This article belongs to the Special Issue Porphyrins and Phthalocyanines: Synthesis, Properties and Applications)

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Open AccessReview

Coumarin–Tetrapyrrolic Macrocycle Conjugates: Synthesis and Applications

by Ana F. R. Cerqueira, Vítor A. S. Almodôvar, Maria G. P. M. S. Neves and Augusto C. Tomé

Molecules 2017, 22(6), 994; https://doi.org/10.3390/molecules22060994 - 15 Jun 2017

Cited by 22 | Viewed by 8221

Abstract

This review covers the synthesis of coumarin–porphyrin, coumarin–phthalocyanine and coumarin–corrole conjugates and their potential applications. While coumarin–phthalocyanine conjugates were obtained almost exclusively by tetramerization of coumarin-functionalized phthalonitriles, coumarin–porphyrin and coumarin–corrole conjugates were prepared by complementary approaches: (a) direct synthesis of the tetrapyrrolic macrocycle [...] Read more.

This review covers the synthesis of coumarin–porphyrin, coumarin–phthalocyanine and coumarin–corrole conjugates and their potential applications. While coumarin–phthalocyanine conjugates were obtained almost exclusively by tetramerization of coumarin-functionalized phthalonitriles, coumarin–porphyrin and coumarin–corrole conjugates were prepared by complementary approaches: (a) direct synthesis of the tetrapyrrolic macrocycle using formylcoumarins and pyrrole or (b) by functionalization of the tetrapyrrolic macrocycle. In the last approach a range of reaction types were used, namely 1,3-dipolar cycloadditions, hetero-Diels–Alder, Sonogashira, alkylation or acylation reactions. This is clearly a more versatile approach, leading to a larger diversity of conjugates and allowing the access to conjugates bearing one to up to 16 coumarin units. Full article

(This article belongs to the Special Issue Porphyrins and Phthalocyanines: Synthesis, Properties and Applications)

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Open AccessReview

Modifications of Porphyrins and Hydroporphyrins for Their Solubilization in Aqueous Media

by Michael Luciano and Christian Brückner

Molecules 2017, 22(6), 980; https://doi.org/10.3390/molecules22060980 - 13 Jun 2017

Cited by 68 | Viewed by 15069

Abstract

The increasing popularity of porphyrins and hydroporphyrins for use in a variety of biomedical (photodynamic therapy, fluorescence tagging and imaging, photoacoustic imaging) and technical (chemosensing, catalysis, light harvesting) applications is also associated with the growing number of methodologies that enable their solubilization in [...] Read more.

The increasing popularity of porphyrins and hydroporphyrins for use in a variety of biomedical (photodynamic therapy, fluorescence tagging and imaging, photoacoustic imaging) and technical (chemosensing, catalysis, light harvesting) applications is also associated with the growing number of methodologies that enable their solubilization in aqueous media. Natively, the vast majority of synthetic porphyrinic compounds are not water-soluble. Moreover, any water-solubility imposes several restrictions on the synthetic chemist on when to install solubilizing groups in the synthetic sequence, and how to isolate and purify these compounds. This review summarizes the chemical modifications to render synthetic porphyrins water-soluble, with a focus on the work disclosed since 2000. Where available, practical data such as solubility, indicators for the degree of aggregation, and special notes for the practitioner are listed. We hope that this review will guide synthetic chemists through the many strategies known to make porphyrins and hydroporphyrins water soluble. Full article

(This article belongs to the Special Issue Porphyrins and Phthalocyanines: Synthesis, Properties and Applications)

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