Manganeseporphyrins immobilized on silica microspheres as biomimetic catalysts hydroxylating cyclohexane with molecular oxygen

Fang

Chemistry An Asian Journal

et al. 2013

Allyloxyporphyrin-functionalized multiwalled carbon nanotubes (MWCNT-TPP) were synthesized by radical polymerization and characterized by FTIR, UV/Vis absorption, and X-ray photoelectron spectroscopy; elemental analysis; TEM; and thermogravimetric analysis. Z-scan studies revealed that this nanohybrid exhibits enhanced nonlinear optical (NLO) properties compared to a control sample consisting of a covalently unattached physical blend of MWCNTs and porphyrin, as well as to the separate MWCNTs and porphyrin. At the wavelengths used, the mechanism of enhanced optical limiting likely involves reverse saturable absorption, nonlinear scattering, and photoinduced electron/energy transfer between the MWCNTs and the porphyrin. The role of electron/energy transfer in the NLO performance of MWCNT-TPP was investigated by Raman and fluorescence spectroscopy.

Section: Nonlinear Optical Studiessupporting

confidence: 72%

Allyloxyporphyrin‐Functionalized Multiwalled Carbon Nanotubes: Synthesis by Radical Polymerization and Enhanced Optical‐Limiting Properties

Fang

Chemistry An Asian Journal

et al. 2013

“…One of the important goals for developing efficient biomimetic models is related to the necessity of developing sustainable, environmentally benign, safe, and clean methodologies for synthetic organic chemistry [92,93,94,95,96,97,98]. In particular, the oxidation reactions needed to convert bulk chemicals (e.g., from petroleum products) into useful products are amongst the most problematic transformations in industrial core technologies (expensive, not selective, and frequently performed under environmentally malignant conditions), hence justifying the huge investment made by different research groups studying the oxidation of aliphatic (alkanes and alkenes) and aromatic hydrocarbons (e.g., toluene, ethylbenzene, and styrene) or phenolic derivatives under homogeneous and heterogeneous conditions [61,62,64,65,99,100,101,102,103,104]. This is also a challenging topic if considering the possibility to use natural and abundant substrates such as terpenes giving rise to high-value compounds with organoleptic or pharmacological interest.…”

Section: Synthetic Metalloporphyrinsmentioning

confidence: 99%

Immobilized Lignin Peroxidase-Like Metalloporphyrins as Reusable Catalysts in Oxidative Bleaching of Industrial Dyes

et al. 2016

Synthetic and bioinspired metalloporphyrins are a class of redox-active catalysts able to emulate several enzymes such as cytochromes P450, ligninolytic peroxidases, and peroxygenases. Their ability to perform oxidation and degradation of recalcitrant compounds, including aliphatic hydrocarbons, phenolic and non-phenolic aromatic compounds, sulfides, and nitroso-compounds, has been deeply investigated. Such a broad substrate specificity has suggested their use also in the bleaching of textile plant wastewaters. In fact, industrial dyes belong to very different chemical classes, being their effective and inexpensive oxidation an important challenge from both economic and environmental perspective. Accordingly, we review here the most widespread synthetic metalloporphyrins, and the most promising formulations for large-scale applications. In particular, we focus on the most convenient approaches for immobilization to conceive economical affordable processes. Then, the molecular routes of catalysis and the reported substrate specificity on the treatment of the most diffused textile dyes are encompassed, including the use of redox mediators and the comparison with the most common biological and enzymatic alternative, in order to depict an updated picture of a very promising field for large-scale applications.

ACS Appl. Mater. Interfaces

“…According to recent observations, , in comparison to nonsupported metalloporphyrins, metalloporphyrin-bound composites display increased stability and selectivity, as well as improved recovery. Generally, inorganic materials are the solid support of choice, due to their robustness and efficiency in inhibiting deactivation of photoactive compounds.…”

Section: Introductionmentioning

confidence: 99%

“…3 – 5 However, inherent drawbacks of these homogeneous systems involve their susceptibility to oxidative self-destruction and aggregation. 6 These phenomena occur when the macrocycles spontaneously self-assemble through noncovalent interactions, forming oligomers and/or dimers. 7 Using nanotechnology-based strategies, such issues can be overcome via immobilization of porphyrins onto supports.…”

Section: Introductionmentioning

confidence: 99%

“…Free-base and metalloporphyrins are well known for exhibiting extraordinary photo- and electrochemical properties. As noted elsewhere, these properties are useful in applications ranging from photodynamic therapy to catalysis. − However, inherent drawbacks of these homogeneous systems involve their susceptibility to oxidative self-destruction and aggregation . These phenomena occur when the macrocycles spontaneously self-assemble through noncovalent interactions, forming oligomers and/or dimers .…”

Section: Introductionmentioning

confidence: 99%

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Preparation of Metalloporphyrin-Bound Superparamagnetic Silica Particles via “Click” Reaction

Hollingsworth

Bhupathiraju

Sun

et al. 2016

A facile approach using click chemistry is demonstrated for immobilization of metalloporphyrins onto the surface of silica-coated iron oxide particles. Oleic-acid stabilized iron oxide nanocrystals were prepared by thermal decomposition of iron(III) acetylacetonate. Their crystallinity, morphology, and superparamagnetism were determined using X-ray diffraction, transmission electron microscopy, and a superconducting quantum interference device. Monodisperse core–shell particles were produced in the silica-coating of iron oxide via microemulsion synthesis. Surface modification of these particles was performed in two steps, which included the reaction of silica-coated iron oxide particles with 3-bromopropyltrichlorosilane, followed by azido-functionalization with sodium azide. Monoalkylated porphyrins were prepared using the Williamson ether synthesis of commercially available tetra(4-hydroxyphenyl) porphyrin with propargyl bromide in the presence of a base. 1H NMR and matrix-assisted laser desorption ionization confirmed the identity of the compounds. The prepared monoalkyne porphyrins were zinc-metalated prior to their introduction to azide-functionalized, silica-coated iron oxide particles in the click reaction. X-ray photoelectron spectroscopy, thermogravimetric analysis, and Fourier transform infrared spectroscopy were used to characterize the surface chemistry after each step in the reaction. In addition, particle size was determined using dynamic light scattering and microscopy. The presented methodology is versatile and can be extended to other photoreactive systems, such as phthalocyanines and boron-dipyrromethane, which may lead to new materials for optical, photonic, and biological applications.