Presence Of Tetraphenylporphyrin Research Articles

Porphyrin mediated photodegradation of tylosin in aqueous media by near-UV light

Tylosin is one of the most used livestock antibiotics, typically employed as a prophylactic and a growth promoter. However, there have been growing concerns that the presence of antibiotics in wastewater sources can contribute to the development of antibiotic resistance. Thus, attempts have been made by researchers to develop techniques capable of removing antibiotics from wastewater. This study evaluated the photocatalytic properties of three types of porphyrin molecules to break down tylosin in deionized water. It was observed that when irradiated with 3.06 eV light the concentration of tylosin decreases by 13.88% after 180 min in the presence of octoethylporphyrin. Similarly, after 180-minute exposure the concentration of tylosin decreases by 17.92% in the presence of tetraphenylporphyrin. Lastly, in the presence of copper (II) tetraphenylporphyrin the concentration of tylosin was observed to decrease by 21.20% after 180-minute exposure to near UV light. Furthermore, it was observed that in the presence of CuTPP the concentration of tylosin decreased by up to 12.54% in a pond water sample over a 24 h period. The initial results indicate that porphyrins present as a plausible candidate for organic photocatalysts to facilitate removal of antibiotic contaminants from aquatic sources.

Synthesis, photooxygenation, and characterization of new angular furoquinolinone derivatives, a new furocoumarin bioisoster

AbstractSynthesis of angular furoquinolinone derivatives with a new skeleton structure was accomplished via Williamson reaction of hydroxyquinolinones with α‐haloketones, such as 3‐chloro‐2‐butanone and phenacyl bromide, followed by treatment with polyphosphoric acid (PPA). The synthesized angular furoquinolinones were photooxygenated in chloroform or dimethyl formamide and in the presence of tetraphenylporphyrin (TPP) as a singlet oxygen sensitizer (1O2). The photooxygenation reactions furnished the photocleaved product through the [2 + 2] cycloaddition reaction. All photoproducts were isolated and fully characterized by spectral analyses.

Study of tetraphenylporphyrins as modifiers of insulin amyloid aggregation.

Amyloid fibrils are rigid β-pleated protein aggregates that are connected with series of harmful diseases and at the same time are promising as base for novel nanomaterials. Thus, design of compounds able to inhibit or redirect those aggregates formation is important both for the biomedical aims and for nanotechnology applications. Here, we studied the effect of tetraphenylporphyrins (metal free, their Cu and Pd complexes, and those functionalized by carboxy and amino groups on periphery) on insulin amyloid self-assembling. The strongest impact on insulin aggregation was demonstrated by a metal-free porphyrin bearing four carboxy groups. This compound strongly suppresses insulin aggregation (about 88% reduction in amyloid-sensitive probe emission) inducing formation of fibrils with the length close to this of free insulin (1.7 ± 0.6 μm as compared with 1.4 ± 0.4 μm, respectively) with an essentially reduced tendency to lateral aggregation. Contrarily, the presence of tetraphenylporphyrin containing four amino groups only slightly affects fibrils' morphology and makes weaker impact on insulin aggregation yield (about 44% reduction). This is explained by the ability of aromatic carboxy groups of 5,10,15,20-(tetra-4-carboxyphenyl)porphyrin to interact with complementary protein-binding groups and thus stabilize the supramolecular complex. For 5,10,15,20-(tetra-4-aminophenyl)porphyrin, full protonation takes place in acidic medium of protein aggregation reaction; this results in the high positive charge of TPPN4 (equal or close to +6) and hence higher contribution of coulombic repulsion to interaction of TPPN4 with insulin. One more possible mechanism of the lower inhibition effect of TPPN4 as compared with TPPC4 could be the more restricted possibility of the former as compared with the latter to form H bonds with insulin groups. It was also shown that metal-free, Pd-containing, and Cu-containing tetraphenylporphyrins without peripheral substituents make almost the same impact on the protein self-assembling. We suppose this to be due to coordination saturation of these metal atoms.

Synthesis and Photooxygenation of Linear and Angular Furocoumarin Derivatives as a Hydroxyl Radical Source: Psoralen, Pseudopsoralen, Isopseudopsoralen, and Allopsoralen

Synthesis of linear and angular furocoumarins with new skeleton structure of potential photobiological feature interest was carried out through Williamson reaction of hydroxycoumarins with 3‐chloro‐2‐butanone followed by cyclization with polyphosphoric acid or by heating in a strongly alkaline solution. The photooxygenation reactions of synthesized furocoumarins were performed in chloroform and in the presence of tetraphenylporphyrin as singlet oxygen sensitizer (1O2). The photooxygenation reactions afforded the photocleaved product through [2 + 2] cycloaddition and the photooxygenated products through ene reaction and [4 + 2] cycloaddition. The photoproducts were isolated and fully characterized by spectral analyses.

Synthesis and Photooxygenation of the Methyl Ester of 11-Homodrim-6,8(9)-Diene-12-Oic Acid

Starting with the methyl 11-homodrim-8-ene-7-oxo-12-oate a two steps synthesis of methyl-11-homodrim-6,8(9)-diene-12-oate was accomplished in 87% overall yield, which on photooxygenation in the presence of tetraphenylporphyrin gave a mixture of methyl esters of 11-homodrim-7-ene-6α,9α-peroxy-12-oic and 11-homodrim-5,8-diene-7-oxo-12-oic acids 21% and 54% yields, respectively.

Photooxygenation of alkenes by molecular oxygen in the presence of porphyrins and chlorin sensitizers under visible light irradiation

Photooxidation of alkenes by molecular oxygen and visible light in the presence of tetraphenylporphyrin (H2TPP) , tetramesitylporphyrin (H2TMP) , tetrakis pentafluorophenylporphyrin (H2TPFPP) and tetrakis(2,3-dimetoxyphenyl)porphyrin T(2,3-OMeP)P and metalloporphyrins such as ClFeTPP , ClMnTMP , ClMnTPP , ClMnTPFPP , ClCoTPP and ZnTPP has been performed. Photooxidation of alkenes with tetraphenylchlorin (H2TPC) as the sensitizer with visible light has also been studied. The conversion rates for alkene oxidation were in the order of free-base porphyrins > chlorin > metalloporphyrins. In the presence of NaN3/Na2SO3 the yield of oxidation products and conversion percentage is considerably reduced, confirming involvement of 1O2 in the mechanism.

A new and efficient aerobic oxidation of aldehydes to carboxylic acids with singlet oxygen in the presence of porphyrin sensitizers and visible light

A new aerobic route is introduced for the oxidation of a variety of aromatic and aliphatic aldehydes to the corresponding carboxylic acid derivatives using molecular oxygen in the presence of tetraphenylporphyrin (H 2 TPP), tetramesitylporphyrin (H 2 TMP), tetrakisdichlorophenylporphyrin (H 2 TDCPP), ZnTPP, and ZnTMP as sensitizers using visible light in an organic solvent. The method has a wide range of applications, does not involve cumbersome work-up, exhibits chemoselectivity, and proceeds under mild reaction conditions. The products are obtained with good conversions and in reasonable reaction times.

Selective photocatalytic epoxidation of cyclooctene by molecular oxygen in the presence of porphyrin sensitizers

Photooxidation of cyclooctene by molecular oxygen in the presence of tetraphenyl porphyrin (H2TPP), tetramesityle porphyrin (H2TMP), tetrakis dichlorophenyl porphyrin (H2TDCPP) and ClFeTMP, ClFeTPP, tetrakis pentaflouro phenyl porphyrin iron chloride (ClFeTPFPP), ClFeTDCPP, ClMnTPP, ClMnTPFPP, ZnTDCPP, ClMnTDCPP, ClCoTDCPP, ClCoTPP and ZnTPP as sensitizers has been studied. 98% cyclooctene conversion with 97% selectivity toward cyclooctene oxide was obtained by H2TDCPP and ZnTDCPP sensitizers. The effect of electron-donating and withdrawing groups on the porphyrin macrocycle ring showed that non-metalled porphyrins with electron-withdrawing groups have higher reactivity (H2TDCPP > H2TPP > H2TMP). The order of reactivity for metalloporphyrins is Zn > Mn > Fe > Co for the same porphyrin ligand. A turnover number (TON) up to 6,000 with selectivity up to 95% was obtained by ClMnTDCPP. In free-base porphyrins and Zn porphyrins, singlet oxygen production is the major route for oxidation, whereas in Mn and Fe porphyrins, two parallel pathways for oxidation products is proposed.

Oxidation reactions of some natural volatile aromatic compounds: anethole and eugenol

trans-Anethole [1-methoxy-4-(trans-prop-1-en-1-yl)benzene] was isolated from anise seed oil (Pimpinella anisum). Its photochemical oxidation with hydrogen peroxide gave the corresponding epoxy derivative together with 4-methoxybenzaldehyde. The thermal oxidation of trans-anethole with 3-chloroperoxybenzoic acid at room temperature resulted in the formation of dimeric epoxide, 2,5-bis(4-methoxyphenyl)-3,6-dimethyl-1,4-dioxane, as the only product. Photochemical oxygenation of trans-anethole in the presence of tetraphenylporphyrin, Rose Bengal, or chlorophyll as sensitizer led to a mixture of 1-(4-methoxyphenyl)prop-2-en-1-yl hydroperoxide and 4-methoxybenzaldehyde. Eugenol was isolated from clove oil [Eugenia caryophyllus (Spreng.)]. It was converted into 2-methoxy-4-(prop-2-en-1-yl)phenyl hydroperoxide by oxidation with hydrogen peroxide under irradiation. Thermal oxidation of eugenol with 3-chloroperoxypenzoic acid at room temperature produced 2-methoxy-4-(oxiran-2-ylmethyl)phenol, while sensitized photochemical oxygenation (in the presence of Rose Bengal or chlorophyll) gave 4-hydroperoxy-2-methoxy-4-(prop-2-en-1-yl)cyclohexa-2,5-dien-1-one.

Oxidation studies on some natural monoterpenes: Citral, pulegone, and camphene

Citral extracted from Cymbopogon citratus (Gramineae) was subjected to photochemical epoxidation with hydrogen peroxide to obtain a mixture of epoxy derivatives at the C2=C3 and C6=C7 double bonds. The thermal oxidation of citral with m-chloroperoxybenzoic acid at room temperature gave only the corresponding 6,7-epoxy derivative as a mixture of E and Z isomers with respect to the C2=C3 double bond. Photosensitized oxygenation of citral in the presence of tetraphenylporphyrin, Rose Bengal, or chlorophyll lead to a mixture of two isomeric hydroperoxides, (2E)-6-hydroperoxy-3,7-dimethylocta-2,7-dienal and (2E,5E)-7-hydroperoxy-3,7-dimethylocta-2,5-dienal. Epoxidation of pulegone isolated from Penny royal oil (Mentha pulegium, Lamiaceae) with hydrogen peroxide under irradiation with a sodium lamp lead to a mixture of cis- and trans-isomeric 2,2,6-trimethyl-1-oxaspiro[2.5]octan-4-ones, whereas under conditions of photosensitized oxygenation two hydroperoxide derivatives, 2-(1-hydroperoxy-1-methylethyl)-5-methylcyclohex-2-en-1-one and 2-hydroperoxy-5-methyl-2-(1-methylethenyl)cyclohexan-1-one, were also formed. Camphene reacted with hydrogen peroxide under irradiation to give a mixture of the corresponding endo- and exo-epoxy derivatives and camphor, while its thermal oxidation with m-chloroperoxybenzoic produced only the two former.

Structure of pluronic F-127 and its tetraphenylporphyrin complexes: X-ray diffraction study

The structure of pluronic F-127 and its complexes with tetraphenylporphyrin has been studied by SAXS and WAXS techniques. It has been shown that the samples prepared via evaporation of chloroform and aqueous solutions of pluronic and its mixtures with tetraphenylporphyrin have a semicrystalline layered structure with the crystalline phase composed of poly(ethylene oxide). The identity period of layers in the samples prepared from the aqueous solution of pluronic has been found to be larger than that in the samples prepared from chloroform solutions of the polymer. This result may apparently be explained by a more pronounced hydration of the samples prepared by the former method. The presence of tetraphenylporphyrin in the samples has an insignificant effect on the parameters of the crystalline and layered structures of pluronic. When the tetraphenylporphyrin content is not larger than its solubilization limit with pluronic, tetraphenylporphyrin concentrates in the amorphous layers of pluronic in the noncrystalline finely dispersed state.

Single Electron Transfer Regioselective Photocatalytic Synthesis of 2-Cyano-1,2,5,6-tetrahydropyridines

A mild and regioselective single electron transfer (SET) photocatalytic general synthesis of 2-cyano-1,2,5,6-tetrahydropyridines from 1,2,5,6-tetrahydropyridines is described. Cyanotrimethylsilane is used as cyanating agent in the presence of tetraphenylporphyrin (TPP) as pbotosensitizer

Thermal and photochemical polymerization of methyl methacrylate in the presence of cholesteric liquid crystals and tetraphenyl porphyrins

Thermal and photochemical homopolymerization of methyl methacrylate (MMA) and copolymerization of MMA and styrene (S) initiated by cholesteryl oleyl carbonate (CHOC) and cholesteryl 2-ethylhexyl carbonate (CHEHC) were studied in the presence of tetraphenylporphyrin (TPP) and cobalt-tetraphenylporphyrin (Co-TPP) at 30 and 65°C. The percentage conversions, molecular weights and tacticities of the homopolymers were determined. The percentage conversion and molecular weights of the polymer formed in the presence of TPP were high and in the presence of Co-TPP they were low. In photopolymerization the percentage conversion was high and the molecular weights were low. In the presence of tetraphenyl-porphyrins the tendency for homopolymerization was high for the copolymerization of MMA with S.