The Use of Spectrophotometry UV-Vis for the Study of Porphyrins

Giovannetti, Rita

doi:10.5772/38797

Cited by 141 publications

(148 citation statements)

References 31 publications

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“…The absorption spectra show a strong absorption band at around 420 nm, corresponding to the Soret bands of the porphyrinyl group. The indicative four Q bands are displayed in the UV‐Vis of L1 and S1 , respectively, around 500—700 nm . In the case of L2 and S2 , when Zn(II) is inserted into the porphyrin ring, the UV‐Vis spectra exhibit two peaks instead of four in the Q regions, due to the modification in the symmetry of the substituted porphyrin ring from D 2h of L1/S1 to the D 4h of L2/S2 .…”

Section: Resultsmentioning

confidence: 99%

“…The indicative four Q bands are displayed in the UV‐Vis of L1 and S1 , respectively, around 500—700 nm . In the case of L2 and S2 , when Zn(II) is inserted into the porphyrin ring, the UV‐Vis spectra exhibit two peaks instead of four in the Q regions, due to the modification in the symmetry of the substituted porphyrin ring from D 2h of L1/S1 to the D 4h of L2/S2 . Two emission bands at 650 nm and 720 nm for L1/S1 and 600 nm and 650 nm for L2/S2 are observed in the emission spectra (Figure c).…”

Section: Resultsmentioning

confidence: 99%

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Order from Chaos: Self‐Assembly of Nanoprism from a Mixture of Tetratopic Terpyridine‐Porphyrin Conformers

Filosa

Wang

et al. 2019

Chin. J. Chem.

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Summary of main observation and conclusion Porphyrins have been widely used in the self‐assembly of metallo‐supramolecules. In this study, we introduced 2,2':6,2"‐terpyridine (tpy) into a porphyrin core to synthesize a tetratopic building block with multiple conformers. During the self‐assembly with Zn(II), such a mixture of conformers was able to form a discrete nanoprism with all building blocks in one conformation. Detailed characterizations, including NMR, ESI‐MS and traveling‐wave ion mobility‐mass spectrometry (TWIM‐MS), all supported the formation of the desired assemblies. AFM and TEM further confirmed the dimensions of assembled nanoprisms. Moreover, the photophysical properties of the ligands and complexes were noticeably different depending upon size and metal ion center.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Order from Chaos: Self‐Assembly of Nanoprism from a Mixture of Tetratopic Terpyridine‐Porphyrin Conformers

Filosa

Wang

et al. 2019

Chin. J. Chem.

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“…The substitution with a weak transition to the first excited state (S0 → S 1 ) in the range between 500-750 nm (the Q bands-I, II, III, IV) is due to the conjugation of 18 π -electrons in the porphyrin macrocycle (Figure 1). Peripheral substituents variations on the porphyrin ring often cause minor changes to the intensity and wavelength [13]. The structures of separated porphyrins (as shown in this work) consisted of β-substitution: four methyl groups (positions C-3,8,13,17) and propionic acid chains (C-2,18 - Figure 1B).…”

Section: Resultsmentioning

confidence: 99%

Hematoporphyrin derivatives: The ultrahigh performance liquid chromatography: Diode array: Electrospray ionization: Mass spectrometry analysis

Zvezdanovic¹,

Petrović²,

Marković³

2017

Adv Techol

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Recent advances in the column technology have led to the development of small particles as stationary phase carriers in reversed-phase liquid chromatography for separation of large scale of molecules. This work represents an application of UHPLC (ultrahigh performance liquid chromatography with 1.9 µm C-18 particles) coupled with ESI-MS (electro spray ionization-mass spectrometry) and DAD (diode array) analysis for the identification of the mixture of porphyrins such as hematoporphyrin and protoporphyrin derivatives, widely known photosensitizers used in medicine. Five porphyrin derivatives were separated and identified in the hematoporphyrin mixture: hematoporphyrin IX, protoporphyrin IX, two hydroxyethyl-vinylderivatives and methyl-ester of protoporphyrin IX.

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“…The powders were dissolved in water at a 10 mg/mL concentration, and their absorbance spectra for the range 350 to 780 nm, at a 5 nm interval, were recorded on a SpectraMax i3x multiplate reader (Molecular corresponding to the CIE 1976 color space were calculated from the measured spectra according to standard guidelines with the illuminant D65 as a reference (CIE, 2004). Color changes were assessed by the CIE coordinates and the spectral change in the longer wavelengths (450-700 nm), which correspond to the so-called heme Q-bands and largely influence the perceived redness of the heme samples (Giovannetti, 2012). For the storage stability tests, seven measurements were taken over a period of about 6 months for all heme-ligand complexes (minimum: 178 days for SN and maximum: 196 days for MeN).…”

Section: Experimental Designmentioning

confidence: 99%

Storage and thermal stability of novel heme‐based pigments prepared from porcine hemoglobin

Chhem-Kieth

Lametsch

Hansen³

et al. 2019

J Food Process Engineering

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The stability of novel meat pigments derived from heme‐enriched extract obtained from porcine hemoglobin was assessed. Four different ligands (sodium nitrite, 4‐methylimidazole, methyl nicotinate, and pyrazine) were used to produce spray‐dried, microencapsulated heme‐ligand complexes. The storage and thermal stabilities of the produced pigments were assessed, over a 6‐months storage period and across a temperature range of 25–75°C. Color measurements and evaluation were made on the dissolved pigments by ultraviolet–visible absorbance spectroscopy and CIELAB color space. All heme‐ligand complexes exhibited a stable red color across the storage period, except for the heme‐methyl nicotinate adduct, which color faded to brown after 30 days of storage. For thermal stability, only the heme‐4‐methylimidazole complex did not retain its red color beyond 55°C. The redness of the heme‐pyrazine complex showed improvement upon heating, which is proposed to be due to the degradation of polymeric heme‐pyrazine structure formed during the ligation process. Practical applications Due to the global effort to reduce nitrite addition in food product, there is an important interest to replace it in processed meat products, wholly or in part. Additionally, the perspective of optimizing the usage of an under‐utilized blood fraction is attractive for the meat industry. The development of a heme pigment derived from porcine blood thus presents a good commercial potential. Two important aspects of such product would be its stability upon storage, or during heat treatment to levels similar to what is used in processed, cooked meat products. This study presents the behavior for those two aspects of different heme‐ligand complexes, and compares the results obtained with a heme pigment produced from the traditionally used nitrite.

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The Use of Spectrophotometry UV-Vis for the Study of Porphyrins

Cited by 141 publications

References 31 publications

Order from Chaos: Self‐Assembly of Nanoprism from a Mixture of Tetratopic Terpyridine‐Porphyrin Conformers

Order from Chaos: Self‐Assembly of Nanoprism from a Mixture of Tetratopic Terpyridine‐Porphyrin Conformers

Hematoporphyrin derivatives: The ultrahigh performance liquid chromatography: Diode array: Electrospray ionization: Mass spectrometry analysis

Storage and thermal stability of novel heme‐based pigments prepared from porcine hemoglobin

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