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9 pages, 2501 KiB

Open AccessArticle

Novel Orange Color Pigments Based on La₃LiMnO₇

by Ryohei Oka, Jun-ichi Koyama, Takuro Morimoto and Toshiyuki Masui

Molecules 2021, 26(20), 6243; https://doi.org/10.3390/molecules26206243 - 15 Oct 2021

Cited by 1 | Viewed by 2533

Abstract

La₃LiMn_1−xTi_xO₇ (0 ≤ x ≤ 0.05) samples were synthesized by a solid-state reaction method, and a single-phase form was observed for the samples in the range of x ≤ 0.03. Crystal structure, optical properties, and [...] Read more.

La₃LiMn_1−xTi_xO₇ (0 ≤ x ≤ 0.05) samples were synthesized by a solid-state reaction method, and a single-phase form was observed for the samples in the range of x ≤ 0.03. Crystal structure, optical properties, and color of the La₃LiMn_1−xTi_xO₇ (0 ≤ x ≤ 0.03) samples were characterized. Strong optical absorption was observed at a wavelength between 400 and 550 nm, and a shoulder absorption peak also appeared around 690 nm in all samples; orange colors were also exhibited. Among the samples synthesized, the most brilliant orange color was obtained at La₃LiMn_0.97Ti_0.03O₇. The redness (a*) and yellowness (b*) values of this pigment were higher than those of the commercially available orange pigments. Therefore, the orange color of this pigment is brighter than those of the commercial products. Since the La₃LiMn_0.97Ti_0.03O pigment is composed of non-toxic elements, it could be a new environmentally friendly inorganic orange pigment. Full article

(This article belongs to the Special Issue Exclusive Feature Papers in Colorants)

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12 pages, 1558 KiB

Open AccessArticle

A Concise Synthesis of a BODIPY-Labeled Tetrasaccharide Related to the Antitumor PI-88

by Juan Ventura, Clara Uriel, Ana M. Gomez, Edurne Avellanal-Zaballa, Jorge Bañuelos, Inmaculada García-Moreno and Jose Cristobal Lopez

Molecules 2021, 26(10), 2909; https://doi.org/10.3390/molecules26102909 - 14 May 2021

Cited by 5 | Viewed by 2593

Abstract

A convergent synthetic route to a tetrasaccharide related to PI-88, which allows the incorporation of a fluorescent BODIPY-label at the reducing-end, has been developed. The strategy, which features the use of 1,2-methyl orthoesters (MeOEs) as glycosyl donors, illustrates the usefulness of suitably-designed BODIPY [...] Read more.

A convergent synthetic route to a tetrasaccharide related to PI-88, which allows the incorporation of a fluorescent BODIPY-label at the reducing-end, has been developed. The strategy, which features the use of 1,2-methyl orthoesters (MeOEs) as glycosyl donors, illustrates the usefulness of suitably-designed BODIPY dyes as glycosyl labels in synthetic strategies towards fluorescently-tagged oligosaccharides. Full article

(This article belongs to the Special Issue Exclusive Feature Papers in Colorants)

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13 pages, 2666 KiB

Open AccessArticle

Sulfanyl Porphyrazines with Morpholinylethyl Periphery—Synthesis, Electrochemistry, and Photocatalytic Studies after Deposition on Titanium(IV) Oxide P25 Nanoparticles

by Tomasz Koczorowski, Wojciech Szczolko, Anna Teubert and Tomasz Goslinski

Molecules 2021, 26(8), 2280; https://doi.org/10.3390/molecules26082280 - 15 Apr 2021

Cited by 14 | Viewed by 2416

Abstract

The syntheses, spectral UV–Vis, NMR, and electrochemical as well as photocatalytic properties of novel magnesium(II) and zinc(II) symmetrical sulfanyl porphyrazines with 2-(morpholin-4-yl)ethylsulfanyl peripheral substituents are presented. Both porphyrazine derivatives were synthesized in cyclotetramerization reactions and subsequently embedded on the surface of commercially available [...] Read more.

The syntheses, spectral UV–Vis, NMR, and electrochemical as well as photocatalytic properties of novel magnesium(II) and zinc(II) symmetrical sulfanyl porphyrazines with 2-(morpholin-4-yl)ethylsulfanyl peripheral substituents are presented. Both porphyrazine derivatives were synthesized in cyclotetramerization reactions and subsequently embedded on the surface of commercially available P25 titanium(IV) oxide nanoparticles. The obtained macrocyclic compounds were broadly characterized by ESI MS spectrometry, 1D and 2D NMR techniques, UV–Vis spectroscopy, and subjected to electrochemical studies. Both hybrid materials, consisting of porphyrazine derivatives embedded on the titanium(IV) oxide nanoparticles’ surface, were characterized in terms of particle size and distribution. Next, they were subjected to photocatalytic studies with 1,3-diphenylisobenzofuran, a known singlet oxygen quencher. The applicability of the obtained hybrid material consisting of titanium(IV) oxide P25 nanoparticles and magnesium(II) porphyrazine derivative was assessed in photocatalytic studies with selected active pharmaceutical ingredients, such as diclofenac sodium salt and ibuprofen. Full article

(This article belongs to the Special Issue Exclusive Feature Papers in Colorants)

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16 pages, 3279 KiB

Open AccessArticle

A Flavone-Based Solvatochromic Probe with A Low Expected Perturbation Impact on the Membrane Physical State

by Simona Concilio, Miriam Di Martino, Anna Maria Nardiello, Barbara Panunzi, Lucia Sessa, Ylenia Miele, Federico Rossi and Stefano Piotto

Molecules 2020, 25(15), 3458; https://doi.org/10.3390/molecules25153458 - 29 Jul 2020

Cited by 5 | Viewed by 2837

Abstract

The study of the cell membrane is an ambitious and arduous objective since its physical state is regulated by a series of processes that guarantee its regular functionality. Among the different methods of analysis, fluorescence spectroscopy is a technique of election, non-invasive, and [...] Read more.

The study of the cell membrane is an ambitious and arduous objective since its physical state is regulated by a series of processes that guarantee its regular functionality. Among the different methods of analysis, fluorescence spectroscopy is a technique of election, non-invasive, and easy to use. Besides, molecular dynamics analysis (MD) on model membranes provides useful information on the possibility of using a new probe, following its positioning in the membrane, and evaluating the possible perturbation of the double layer. In this work, we report the rational design and the synthesis of a new fluorescent solvatochromic probe and its characterization in model membranes. The probe consists of a fluorescent aromatic nucleus of a 3-hydroxyflavone moiety, provided with a saturated chain of 18 carbon atoms and a zwitterionic head so to facilitate the anchoring to the polar heads of the lipid bilayer and avoid the complete internalization. It was possible to study the behavior of the probe in GUV model membranes by MD analysis and fluorescence microscopy, demonstrating that the new probe can efficiently be incorporated in the lipid bilayer, and give a color response, thanks to is solvatochromic properties. Moreover, MD simulation of the probe in the membrane supports the hypothesis of a reduced perturbation of the membrane physical state. Full article

(This article belongs to the Special Issue Exclusive Feature Papers in Colorants)

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17 pages, 2096 KiB

Open AccessArticle

1,3,4-Thiadiazole-Containing Azo Dyes: Synthesis, Spectroscopic Properties and Molecular Structure

by Agnieszka Kudelko, Monika Olesiejuk, Marcin Luczynski, Marcin Swiatkowski, Tomasz Sieranski and Rafal Kruszynski

Molecules 2020, 25(12), 2822; https://doi.org/10.3390/molecules25122822 - 18 Jun 2020

Cited by 26 | Viewed by 5655

Abstract

Three series of azo dyes derived from 2-amino-5-aryl-1,3,4-thiadiazoles and aniline, N,N-dimethylaniline and phenol were synthesized in high yields by a conventional diazotization-coupling sequence. The chemical structures of the prepared compounds were confirmed by ¹H-NMR, ¹³C-NMR, IR, UV-Vis spectroscopy, mass spectrometry [...] Read more.

Three series of azo dyes derived from 2-amino-5-aryl-1,3,4-thiadiazoles and aniline, N,N-dimethylaniline and phenol were synthesized in high yields by a conventional diazotization-coupling sequence. The chemical structures of the prepared compounds were confirmed by ¹H-NMR, ¹³C-NMR, IR, UV-Vis spectroscopy, mass spectrometry and elemental analysis. In addition, the X-ray single crystal structure of a representative azo dye was presented. For explicit determination of the influence of a substituent on radiation absorption in UV-Vis range, time-dependent density functional theory calculations were performed. Full article

(This article belongs to the Special Issue Exclusive Feature Papers in Colorants)

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14 pages, 2904 KiB

Open AccessFeature PaperArticle

Spectroscopic Behaviour of Two Novel Azobenzene Fluorescent Dyes and Their Polymeric Blends

by Rosita Diana, Ugo Caruso, Stefano Piotto, Simona Concilio, Rafi Shikler and Barbara Panunzi

Molecules 2020, 25(6), 1368; https://doi.org/10.3390/molecules25061368 - 17 Mar 2020

Cited by 14 | Viewed by 4285

Abstract

Two novel symmetrical bis-azobenzene red dyes ending with electron-withdrawing or donor groups were synthesized. Both chromophores display good solubility, excellent chemical, and thermal stability. The two dyes are fluorescent in solution and in the solid-state. The spectroscopic properties of the neat crystalline solids [...] Read more.

Two novel symmetrical bis-azobenzene red dyes ending with electron-withdrawing or donor groups were synthesized. Both chromophores display good solubility, excellent chemical, and thermal stability. The two dyes are fluorescent in solution and in the solid-state. The spectroscopic properties of the neat crystalline solids were compared with those of doped blends of different amorphous matrixes. Blends of non-conductive and of emissive and conductive host polymers were formed to evaluate the potential of the azo dyes as pigments and as fluorophores. Both in absorbance and emission, the doped thin layers have CIE coordinates in the spectral region from yellow to red. The fluorescence quantum yield measured for the brightest emissive blend reaches 57%, a remarkable performance for a steadily fluorescent azo dye. A DFT approach was employed to examine the frontier orbitals of the two dyes. Full article

(This article belongs to the Special Issue Exclusive Feature Papers in Colorants)

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13 pages, 4454 KiB

Open AccessFeature PaperArticle

Ready Access to Molecular Rotors Based on Boron Dipyrromethene Dyes-Coumarin Dyads Featuring Broadband Absorption

by Ernesto Enríquez-Palacios, Teresa Arbeloa, Jorge Bañuelos, Claudia I. Bautista-Hernández, José G. Becerra-González, Iñigo López-Arbeloa and Eduardo Peña-Cabrera

Molecules 2020, 25(4), 781; https://doi.org/10.3390/molecules25040781 - 12 Feb 2020

Cited by 3 | Viewed by 3907

Abstract

Herein we report on a straightforward access method for boron dipyrromethene dyes (BODIPYs)-coumarin hybrids linked through their respective 8- and 6- positions, with wide functionalization of the coumarin fragment, using salicylaldehyde as a versatile building block. The computationally-assisted photophysical study unveils broadband absorption [...] Read more.

Herein we report on a straightforward access method for boron dipyrromethene dyes (BODIPYs)-coumarin hybrids linked through their respective 8- and 6- positions, with wide functionalization of the coumarin fragment, using salicylaldehyde as a versatile building block. The computationally-assisted photophysical study unveils broadband absorption upon proper functionalization of the coumarin, as well as the key role of the conformational freedom of the coumarin appended at the meso position of the BODIPY. Such free motion almost suppresses the fluorescence signal, but enables us to apply these dyads as molecular rotors to monitor the surrounding microviscosity. Full article

(This article belongs to the Special Issue Exclusive Feature Papers in Colorants)

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Review

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31 pages, 4868 KiB

Open AccessReview

Zinc (II) and AIEgens: The “Clip Approach” for a Novel Fluorophore Family. A Review

by Rosita Diana and Barbara Panunzi

Molecules 2021, 26(14), 4176; https://doi.org/10.3390/molecules26144176 - 9 Jul 2021

Cited by 28 | Viewed by 3416

Abstract

Aggregation-induced emission (AIE) compounds display a photophysical phenomenon in which the aggregate state exhibits stronger emission than the isolated units. The common term of “AIEgens” was coined to describe compounds undergoing the AIE effect. Due to the recent interest in AIEgens, the search [...] Read more.

Aggregation-induced emission (AIE) compounds display a photophysical phenomenon in which the aggregate state exhibits stronger emission than the isolated units. The common term of “AIEgens” was coined to describe compounds undergoing the AIE effect. Due to the recent interest in AIEgens, the search for novel hybrid organic–inorganic compounds with unique luminescence properties in the aggregate phase is a relevant goal. In this perspective, the abundant, inexpensive, and nontoxic d¹⁰ zinc cation offers unique opportunities for building AIE active fluorophores, sensing probes, and bioimaging tools. Considering the novelty of the topic, relevant examples collected in the last 5 years (2016–2021) through scientific production can be considered fully representative of the state-of-the-art. Starting from the simple phenomenological approach and considering different typological and chemical units and structures, we focused on zinc-based AIEgens offering synthetic novelty, research completeness, and relevant applications. A special section was devoted to Zn(II)-based AIEgens for living cell imaging as the novel technological frontier in biology and medicine. Full article

(This article belongs to the Special Issue Exclusive Feature Papers in Colorants)

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25 pages, 6928 KiB

Open AccessReview

The Role of Zinc(II) Ion in Fluorescence Tuning of Tridentate Pincers: A Review

by Rosita Diana and Barbara Panunzi

Molecules 2020, 25(21), 4984; https://doi.org/10.3390/molecules25214984 - 28 Oct 2020

Cited by 53 | Viewed by 5109

Abstract

Tridentate ligands are simple low-cost pincers, easy to synthetize, and able to guarantee stability to the derived complexes. On the other hand, due to its unique mix of structural and optical properties, zinc(II) ion is an excellent candidate to modulate the emission pattern [...] Read more.

Tridentate ligands are simple low-cost pincers, easy to synthetize, and able to guarantee stability to the derived complexes. On the other hand, due to its unique mix of structural and optical properties, zinc(II) ion is an excellent candidate to modulate the emission pattern as desired. The present work is an overview of selected articles about zinc(II) complexes showing a tuned fluorescence response with respect to their tridentate ligands. A classification of the tridentate pincers was carried out according to the binding donor atom groups, specifically nitrogen, oxygen, and sulfur donor atoms, and depending on the structure obtained upon coordination. Fluorescence properties of the ligands and the related complexes were compared and discussed both in solution and in the solid state, keeping an eye on possible applications. Full article

(This article belongs to the Special Issue Exclusive Feature Papers in Colorants)

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