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Porous Polymer for Heterogeneous Catalysis
Published in Inamuddin, Mohd Imran Ahamed, Rajender Boddula, Porous Polymer Science and Applications, 2022
Vivek Mishra, Simran Aggarwal, Shubham Pandey
Selective oxidation of alcohols is done to yield aldehydes and ketones which are used extensively in the pharmaceutical and plastic industry. These reactions are generally catalyzed by Au, Ru, or Pd catalysts due to their high activity, selectivity, and reusability but their limited availability and high cost have restricted their applications. Therefore, developing low-cost and environmentally benign transition metal-based catalysts is highly desirable. Porphyrin is a conjugated heterocycle with four pyrrolidine units interconnected by methine bridges. The four N atoms of porphyrin coordinate with various metal ions to give metalloporphyrins which are widely used as catalysts. These N atoms can strongly bind with Mn species leading to the formation of stable heterogeneous Mn-based catalysts. Additionally, the high conjugation helps in the flow of electrons to and from the valence ions resulting in an easy reduction of metals and enhanced reactivity of these catalysts in alcohol oxidation. Chen et al.78 synthesized various porphyrin-based POP by taking 1,3,5-Triformylphloroglucinol (TFP) and 2,2′-dipyrrolylmethane (DPM) as the precursor. The POPs were further reacted with Mn(OAc)2.4H2O to give various Mn/TFP-DPMs.
Biomass Delignification with Biomimetic Enzyme Systems
Published in Jorge M.T.B. Varejão, Biomass, Bioproducts and Biofuels, 2022
Porphyrins are naturally occurring compounds in many enzymes involved in several important biological metabolic processes, such as a prosthetic group, as oxygen/carbon dioxide transporters, cytochromes, peroxidases, catalase, among others. Synthetic counterparts have a wide range of use in different applications, such as notable examples in photodynamic therapy (PDT), with use in cancer detection and therapy (Deng et al. 2020), in the preparation of blood substitutes (Kitagishi et al. 2017), in catalysis for adding oxygen to a variety of substrates (Meireles et al. 2020), in the design of new molecular electronic devices (Ahmed and Manna 2020), among many others. Meso tetrakis phenyl porphyrins have almost exclusively been used in different applications due to their ease of synthesis and isolation. The optimization of its effectiveness in such applications required the design and preparation of porphyrins with the specific requirements to fulfill the desired properties, such as spectral modifications, solubility manipulation, etc. Wider use and manipulation of their properties is necessary, so the evolution of synthetic methods that can make them easier to prepare, with lower prices is desirable.
Thermal Nanosensors
Published in Vinod Kumar Khanna, Nanosensors, 2021
A porphyrin is any one of a class of water-soluble, nitrogenous biological pigments (biochromes), derivatives of which include the hemoproteins (porphyrins combined with metals and protein). A porphyrin is an organic compound that contains four pyrrole rings. A pyrrole is a pentagon-shaped ring of four carbon atoms with a nitrogen atom at one corner (C4H5N). The porphyrins are an enormous group of organic compounds, found all over the living world. They are universal, found in most living cells of animals and plants, where they perform a wide variety of functions. The special property of porphyrins is that they bind metals. The four nitrogen atoms in the middle of the porphyrin molecule act as teeth: they can grab and hold metal ions such as magnesium (Mg), iron (Fe), zinc (Zn), nickel (Ni), cobalt (Co), copper (Cu), and silver (Ag).
Analysis of porphyrin, PETIM and zinc porphyrin dendrimers by atom-bond sum-connectivity index for drug delivery
Published in Molecular Physics, 2023
Rong-Rong Huang, Sahar Aftab, Sadia Noureen, Adnan Aslam
Dendrimers for drug delivery are employed using a nanoconstruct approach. They have evolved into an important class of nanostructured carriers for the progress of nanomedicine in the treatment of a wide range of disorders. Because of their structural diversity and versatility, bacteria have been employed to deliver medications and genes in a number of ways. Porphyrin is required for haemoglobin to function. Heme is a protein found in red blood cells that links to porphyrin, binds iron, and delivers oxygen from the pulmonary system to the body's other organs. To put it another way, our bodies employ porphyrin to create haemoglobin. It is used in the treatment of porphyria (which refers to a category of disorders caused by an increase in the natural chemicals in the body that produce replete porphyrin). To limit the body's natural formation of porphyrin, it is medicated with an ‘injection of hemin’, a heme-like medication.
Aluminum complexes bearing Schiff base ligands derived from porphyrin derivatives and their application in lactide polymerization
Published in Journal of Coordination Chemistry, 2021
Bo Gao, Guiqiu Huang, Dongni Li
Porphyrin is an 18 π aromatic macrocyclic compound with important roles in diverse areas of scientific research, owing to its unique electronic and optical properties [23]. Porphyrins and metalated porphyrins, in catalysis, have attracted organic and inorganic chemists because of their molecular structures [24]. The highly symmetrical D4h planar structure of metalloporphyrin has inspired study of metal porphyrins as catalysts to catalyze the ROP of cyclic esters [25–27]. The stereoselective polymerization of ROP of rac-lactide initiated by aluminum porphyrin complexes supported by Schiff bases have not been reported (see Schemes 1 and 2). Encouraged by the effective use of aluminum complexes base on Schiff bases [17–22], and combining our previous studies on the syntheses and properties of porphyrins [28, 29], due to the introduction of Schiff bases, the volume of porphyrin ligand increases, we believe the aluminum complex based on this modified porphyrin with Schiff bases is a good initiator for stereoselective polymerization of rac-LA. In this work, the experimental results of the syntheses and characterization of aluminum porphyrin complexes based on Schiff bases are reported, which act as initiators to polymerize rac-LA to afford isotactically enriched PLA.
Highly reactive μ-carbido diiron tetraphenylporphine oxo-species: chemical generation and the oxidation ability
Published in Journal of Coordination Chemistry, 2018
S. V. Zaitseva, E. Yu. Tyulyaeva, O. R. Simonova, S. A. Zdanovich, D. V. Tyurin, O. I. Koifman
Porphyrin complexes are widely used by nature in the active sites of enzymes responsible for catalytic aerobic oxidations, reduction and transport of dioxygen, metabolism of pharmaceuticals and destruction of peroxides. The peroxidase activity of iron-containing enzymes determined by their ability to initiate the metabolism and detoxification of peroxides by oxidation with the release of O2 is of great importance for the antioxidant system of the human body. Complexes with synthetic ligands can be also regarded as related to bioinspired chemistry. Dimeric metalloporphyrin species can exhibit even better catalytic properties than those of mononuclear counterparts [1–7]. Indeed, generation of active oxidizing species in the course of diiron macrocyclic constructions can increase their oxidation state by more than two redox equivalents. This high oxidation state is stabilized by charge delocalization at the two iron sites as well as at two aromatic ligands similar to the (P+•)FeIV=O (Compound I) species in cytochrome P-450 [8].