Comprehensive Coordination Chemistry II Volume 832 || Nickel

The emergence of multidrug resistant bacterium threatens to unravel global healthcare systems, built up over centuries of medical research and development. Current antibiotics have little resistance against this onslaught as bacterium strains can quickly evolve effective defense mechanisms. Fortunately, alternative therapies exist and, at the forefront of research lays the photodynamic inhibition approach mediated by porphyrin based photosensitizers. This review will focus on the development of various porphyrins compounds and their incorporation as small molecules, into polymers, fibers and thin films as practical therapeutic agents, utilizing photodynamic therapy to inhibit a wide spectrum of bacterium. The use of photodynamic therapy of these porphyrin molecules are discussed and evaluated according to their electronic and bulk material effect on different bacterium strains. This review also provides an insight into the general direction and challenges facing porphyrins and derivatives as full-fledged therapeutic agents and what needs to be further done in order to be bestowed their rightful and equal status in modern medicine, similar to the very first antibiotic; penicillin itself. It is hoped that, with this perspective, new paradigms and strategies in the application of porphyrins and derivatives will progressively flourish and lead to advances against disease.

A Perspective on the Trends and Challenges Facing Porphyrin-Based Anti-Microbial Materials

(57) [Summary]
The present application relates to novel pharmaceutical and cosmetic compositions containing essential oils in combination with herbs and / or spices. The composition may be used orally and topically.

Essential oil composition

Diverse biological activities of vanadium(V) drugs mainly arise from their abilities to inhibit phosphatase enzymes and to alter cell signaling. Initial interest focused on anti-diabetic activities but has shifted to anti-cancer and anti-parasitic drugs. V-based anti-diabetics are pro-drugs that release active components (e.g., H2 VO4- ) in biological media. By contrast, V anti-cancer drugs are generally assumed to enter cells intact; however, speciation studies indicate that nearly all drugs are likely to react in cell culture media during in vitro assays and the same would apply in vivo. The biological activities are due to VV and/or VIV reaction products with cell culture media, or the release of ligands (e.g., aromatic diimines, 8-hydroxyquinolines or thiosemicarbazones) that bind to essential metal ions in the media. Careful consideration of the stability and speciation of V complexes in cell culture media and in biological fluids is essential to design targeted V-based anti-cancer therapies.

Stabilities and Biological Activities of Vanadium Drugs: What is the Nature of the Active Species?

Porphyrins have long been used as fluorescence imaging contrast agents. However, they often suffer from aggregation-caused quenching (ACQ) which limits their maximal imaging ability. It is desirable to design new porphyrin derivatives exhibiting aggregation induced emission enhancement (AIEE) with a high photoluminescence (PL) intensity in an aggregated state. Herein, we transform porphyrin from an ACQ molecule to an AIEE one by simply decorating a porphyrin core with four tetraphenylethene arms. We further encapsulate the new AIE porphyrin into nanoparticles and examine their fluorescence imaging in vitro with HeLa cells. This research demonstrates a general approach to produce AIEE porphyrin derivatives that could potentially enhance their performance in various areas.

Decoration of porphyrin with tetraphenylethene: converting a fluorophore with aggregation-caused quenching to aggregation-induced emission enhancement

Results of investigation of the physicochemical properties of zinc complexes containing substituted phenols as axial ligand having general formula [X-Zn-t(p-CH3) PP] [where X = different phenolates as axial ligand] in impurity-free organic solvent are presented. The four-coordinated zinc porphyrin accepts one axial ligand in 1 : 1 molar ratio to form five-coordinated complex, which is purified by column chromatography and characterized by physicochemical, biological evaluation and TGA/DTA studies. Absorption spectra show two principal effects: a red shift for phenols bearing substituted electron releasing groups (−CH3, −NH2) and blue shift for phenols bearing electron withdrawing groups (−NO2, −Cl) relative to Zn-t(p-CH3) PP, respectively. 1H NMR spectra show that the protons of the phenol ring axially attached to the central metal ion are merged with the protons of the porphyrin ring. Fluorescence spectra show two fluorescence peaks in the red region with emission ranging from 550 nm to 700 nm. IR spectra confirm the appearance of Zn-NPor and Zn-O vibrational frequencies, respectively. According to the thermal studies, the complexes have a higher thermal stability and the decomposition temperature of these complexes depends on the axial ligation. The respective complexes of X-ZnII-t(p-CH3) PP were found to possess higher antifungal activity (up to 90%) and higher in vitro cytotoxicity against human cancer cells lines.

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Synthesis and Spectroscopic and Biological Activities of Zn(II) Porphyrin with Oxygen Donors

A series of parasubstituted tetraphenylporphyrin zirconium(IV) salicylate complexes (SA/5-SSAZr(IV)RTPP, R = p-H, p-CH3, p-NO2, p-Cl, SA = salicylate, and 5-SSA = 5-sulfosalicylate) have been synthesized, and the spectral properties of free base porphyrins, their corresponding metallated, and axially ligated zirconium(IV) porphyrin compounds were compared with each other. A detailed analysis of ultraviolet-visible (UV-vis), proton nulcear magnetic resonance (1H NMR) spectroscopy, infrared (IR) spectroscopy, and elemental analysis suggested the transformation from free base porphyrins to zirconium(IV) porphyrins. The ability of the metal in this complex for extra coordination of solvent molecules was confirmed by ESI-MS spectra. Besides the fluorescence, cyclic voltammetry, and thermogravimetric studies, the complexes were also screened for antimicrobial and anticancer activities. Among all the complexes, 5-SSAZr(p-NO2TPP) shows high antibacterial activity.

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Synthesis, Spectroscopic, and Biological Studies on New Zirconium(IV) Porphyrins with Axial Ligand

Crystallographic elucidations of indium(III) porphyrin conformations, morphology and aggregation behaviour: Comparative optical study of free base porphyrins and their indium(III) derivatives at varying pH

The synthesis and spectroscopic characterization of new axially ligated indium(III) porphyrin complexes were reported. Chloroindium(III) porphyrin (TPPIn-Cl) was obtained in good yield by treating the corresponding free base with indium trichloride. The action of the different phenols on chloroderivatives (TPPIn-Cl) led to the corresponding phenolato complexes (TPPIn-X). These derivatives were characterized on the basis of mass spectrometry, 1H-NMR, IR, and UV-visible data. The separation and isolation of these derivatives have been achieved through chromatography. The spectral properties of free base porphyrin and its corresponding metallated and axially ligated indium(III) porphyrin compounds were compared with each other. A detailed analysis of UV-Vis, 1H-NMR, and IR suggested the transformation from free base porphyrin to indium(III) porphyrin. Besides, 13C-NMR and fluorescence spectra were also reported and interpreted. The stability of these derivatives has also been studied through thermogravimetry. The complexes were also screened for anticancerous activities. Among all the complexes, 4-MePhO-InTPP shows highest anticancerous activity. The title complexe, TPPIn-X (where X = different phenolates), represents a five-coordinate indium(III) porphyrin complex in a square-pyramidal geometry with the phenolate anion as the axial ligand.

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Synthesis and Spectroscopic Characterization of Some New Axially Ligated Indium(III) Macrocyclic Complexes and Their Biological Activities.

Abstract 5, 10, 15, 20-tetrakis-(4-chlorophenyl) porphyrin, H2TTPCl4, has been isolated as a new polymorph following the modified Adler’s method and its X-ray crystal structure solved. The new polymorph (I) crystallises in the monoclinic space group, P21/n with a = 10.1574(5) Å, b = 8.9827(4) Å, c = 20.9350(8) Å, β = 102.532(4)°, V = 1864.62(15) Å3, Z = 2. The previously found polymorph, prepared using Lindsay method was crystallised in monoclinic space group, P21/a with a = 15.776 (13) Å, b = 8.646 (3) Å, c = 14.087 (5) Å, β = 96.05 (5)°, V = 1910.7 (3) Å3, Z = 2. The main difference between the two polymorphs seems to be the different packing arrangement of molecules in their crystal lattices. The dramatic self aggregation property of new polymorph (I) has also been investigated. The investigation reveals that under certain conditions of solute concentration and pH of the media, the compound exhibits a strong tendency to exist in a prominent self aggregated state in head-to-tail type (j-aggregation) molecular alignment. The self association behaviour of (I) was confirmed by UV-Vis absorption spectra, performed in chloroform by varying concentrations and pH changes and 1H NMR spectra, performed in deuterated chloroform at varying concentrations and their results have been discussed in detail.

Synthesis and single crystal structure of a new polymorph of 5, 10, 15, 20-tetrakis-(4-chlorophenyl) porphyrin, H2TTPCl4: Spectroscopic investigation of aggregation of H2TTPCl4

Gauri D. Bajju

Papers

Synthesis and Spectroscopic and Biological Activities of Zn(II) Porphyrin with Oxygen Donors

Synthesis, Spectroscopic, and Biological Studies on New Zirconium(IV) Porphyrins with Axial Ligand

Crystallographic elucidations of indium(III) porphyrin conformations, morphology and aggregation behaviour: Comparative optical study of free base porphyrins and their indium(III) derivatives at varying pH

Synthesis and Spectroscopic Characterization of Some New Axially Ligated Indium(III) Macrocyclic Complexes and Their Biological Activities.

Synthesis and single crystal structure of a new polymorph of 5, 10, 15, 20-tetrakis-(4-chlorophenyl) porphyrin, H2TTPCl4: Spectroscopic investigation of aggregation of H2TTPCl4