Green synthesis mechanism

M. L. H. Green, Studies on Synthesis, Mechanism and Reactivity of Some Organo— Molybdenum and -Tungsten Compounds, Pure Appl. Chem. 50, 27-35 (1978). 

MECHANISM OF GREEN SYNTHESIS OF GOLD AND SILVER NANOPARTICLES... 

The mechanism of green synthesis of gold and silver nanoparticles is due to the presence of polyphenol in plant extracts which is responsible for reduction of nanoparticles. The molecular mechanism which gives the antioxidant properties of gold and silver nanoparticles endorses reduction of Au ions to Au atoms and Ag ions to Ag atoms (Figure 6.8). This reduction takes place by abstraction of hydrogen because of the OH groups in the polyphenol... 

Mechanism of green synthesis of gold and silver nanoparticles. 

Parida, U.K., Biswal, S.K., Bindhani, B.K., 2014b. Green synthesis and characterization of gold nanoparticles study of its biological mechanism in human SUDHL-4 cell line. Adv. Biol. Chem. 4, 360-375. 

G.D. Yadav, A.R. Yadav, selective green synthesis of 1,5-benzodiazepine over modified heteropolyadd as nanocatalyst kinetics and mechanism, Ind. Eng. Chem. Res. 52 (2013) 17812-17820. 

Barondeau DP, Putnam CD, Kassmann CJ, Tainer JA, Getzoff ED (2003) Mechanism and energetics of green fluorescent protein chromophore synthesis revealed by trapped intermediate structures. Proc Natl Acad Sci USA 100 12111-12116... 

Green, D.E. Gibson, D.M. (1960). Fatty acid oxidation and synthesis. In Metabolic Pathways (Greenberg, D.M. Ed.) Vol. I, pp. 301-340. Academic Press, New York. Lipmann, F. (1948-1949). Biosynthetic Mechanisms. Harvey Lectures XLIV, 99-123. Vagelos, P.R. (1964). Lipid metabolism. Annu. Rev. Biochem. 33, 139-172. 

The molecular target site of triketone herbicides is the enzyme -hydroxyphenylpyruvate dioxygenase (HPPD). Inhibition of this enzyme disrupts the biosynthesis of carotenoids and causes a bleaching (loss of chlorophyll) effect on the foliage similar to that observed with inhibitors ofphytoene desaturase (e.g. norflurazon). However, the mechanism of action of HPPD inhibitors is different. Inhibtion of HPPD stops the synthesis of homogen tisate (HGA), which is a key precursor of the 8 different tocochromanols (tocopherols and tocotrienols) and prenyl quinones. In the absence of prenylquinone plastoquinone, phytoene desaturase activity is interrupted. The bleaching of the green tissues ensues as if these compounds inhibited phytoene desaturase. 

The photoreductive synthetic process that promotes the assimilation of carbon dioxide into carbohydrates, other reduced metabolites, as well as ATP (synthesis of the latter is termed photophosphorylation). Photosynthesis is the primary mechanism for transducing solar energy into biomass, and green plants utilize chlorophyll a to capture a broad spectrum of solar radiant energy reaching the Earth s surface. Photosynthetic bacteria typically produce NADPH, the reductive energy of which is converted to ATP. 

Partially hydrogenated quinoline cores are also present in some important bioactive compounds. For example, the 4-aza-analogs of Podophyllotoxin, a plant lignan that inhibits microtubule assembly, revealed to be more potent and less toxic anticancer agents. In 2006, Ji s group reported a green multicomponent approach to a new series of these derivatives, consisting of the reaction of either tetronic acid or 1,3-indanedione with various aldehydes and substituted anilines in water under microwave irradiation conditions (Scheme 26) [107]. For this efficient and eco-friendly transformation, the authors proposed a mechanism quite similar to the one that was postulated for the synthesis of tetrahydroquinolines in the precedent section. 

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