@article { ISI:000232129900010, title = {Biosynthesis of gold and silver nanoparticles using emblica officinalis fruit extract, their phase transfer and transmetallation in an organic solution}, journal = {Journal of Nanoscience and Nanotechnology}, volume = {5}, number = {10}, year = {2005}, month = {OCT}, pages = {1665-1671}, publisher = {AMER SCIENTIFIC PUBLISHERS}, type = {Article}, address = {26650 THE OLD RD, STE 208, VALENCIA, CA 91381-0751 USA}, abstract = {

The design, synthesis and characterization of biologically synthesized nanomaterials have become an area of significant interest. In this paper, we report the extracellular synthesis of gold and silver nanoparticles using Emblica Officinalis (amla, Indian Gooseberry) fruit extract as the reducing agent to synthesize Ag and Au nanoparticles, their subsequent phase transfer to an organic solution and the transmetallation reaction of hydrophobized silver nanoparticles with hydrophobized chloroaurate ions. On treating aqueous silver sulfate and chloroauric acid solutions with Emblica Officinalis fruit extract, rapid reduction of the silver and chloroaurate ions is observed leading to the formation of highly stable silver and gold nanoparticles in solution. Transmission Electron Microscopy analysis of the silver and gold nanoparticles indicated that they ranged in size from 10 to 20 nm and 15 to 25 nm respectively. Ag and Au nanoparticles thus synthesized were then phase transferred into an organic solution using a cationic surfactant octadecylamine. Transmetallation reaction between hydrophobized silver nanoparticles and hydrophobized chloroaurate ions in chloroform resulted in the formation of gold nanoparticles.

}, keywords = {Biosynthesis, Nanomaterials, Phase transfer, Transmetallation}, issn = {1533-4880}, doi = {10.1166/jnn.2005.184}, author = {Ankamwar, Balaprasad and Damle, C. and Ahmad, Absar and Sastry, M.} } @article { ISI:000270471100021, title = {Porous anisotropic metal nanostructures through controlled transmetallation across a dialysis membrane}, journal = {Journal of Nanoscience and Nanotechnology}, volume = {9}, number = {11}, year = {2009}, month = {NOV}, pages = {6401-6408}, publisher = {AMER SCIENTIFIC PUBLISHERS}, address = {25650 NORTH LEWIS WAY, STEVENSON RANCH, CA 91381-1439 USA}, abstract = {

Nanostructured metals with hollow interiors are of technological importance due to their unique optoelectronic properties and enhanced surface area. We describe herein, a novel method for the synthesis of anisotropic gold and palladium nanoparticles through a simple galvanic replacement reaction across a semi-permeable dialysis membrane. The control over the reaction kinetics achieved by the presence of membrane enables one to tune the bimetal composition, particle porosity and morphology. Rapid outward diffusion of silver ions generated from the sacrificial silver nanoparticles even at room temperatures prevents the precipitation of high quantities of silver chloride, thereby circumventing the need for product purification. The porous anisotropic nanostructures have potential applications in catalysis, cell imaging and therapeutics.

}, keywords = {Ag/Pd Nanostructures, Anisotropic Nanoparticles, Dialysis, Galvanic Replacement, Porous nanostructures, Silver Nanotriangles, Silver Nanowires, Transmetallation}, issn = {1533-4880}, doi = {10.1166/jnn.2009.1350}, author = {Shukla, Sourabh and Pasricha, Renu and Sastry, Murali} } @article { ISI:000267381100014, title = {Synthesis of catalytically active porous platinum nanoparticles by transmetallation reaction and proposition of the mechanism}, journal = {Small}, volume = {5}, number = {12}, year = {2009}, month = {JUN}, pages = {1467-1473}, publisher = {WILEY-V C H VERLAG GMBH}, address = {PO BOX 10 11 61, D-69451 WEINHEIM, GERMANY}, abstract = {

A facile method for the synthesis of porous platinum nanoparticles by transmetallation reactions between sacrificial nickel nanoparticles and chloroplatinic acid (H(2)PtCl(6)) in solution, as well as at the constrained environment of the air water interface, using a Langmuir-Blodgett instrumental setup is presented. To carry out the transmetallation at the air-water interface hydrophobized nickel nanoparticles are assembled as a monolayer on the sub phase containing platinum ions. The porous Pt nanoparticles obtained as a result of the reaction are found to act as extremely good catalysts for hydrogenation reaction. The products are well characterized by TEM, HRTEM, EDAX, and STEM. Attempts are made to postulate the plausible mechanism of this reaction to generate this kind of nanoparticle with controllable geometric shape and structure. This simple strategy has the potential to synthesize other nanomaterials of interest too.

}, keywords = {Catalysts, Interfaces, Nickel nanoparticles, porous platinum, Transmetallation}, issn = {1613-6810}, doi = {10.1002/smll.200801863}, author = {Pasricha, Renu and Bala, Tanushree and Biradar, Ankush V. and Shubhangi B. Umbarkar and Sastry, Murali} } @article {46910, title = {Transmetallation vs adduct: diverse reactivity of N,O-ketiminato germylene with [Cp*MCl2](2) (M = Rh or Ir; Cp* = eta(5)-C5Me5) and MCl5 (M = Nb and Ta)}, journal = {Journal of Organometallic Chemistry}, volume = {911}, year = {2020}, month = {APR }, pages = {121142}, type = {Article}, abstract = {

The reactions of the germylenes, [(Dipp)NCMeCHCORGeCl] (1a: R = Me, 1b: R = Ph) with [Ir2Cl2(mu-Cl)(2)(eta(5)-Cp*)(2)] led to the formation of the adducts [(Dipp)NCMeCHCORGeClIrCl2Cp*] (3a: R = Me and 3b: R = Ph). On the other hand, [Rh2Cl2(mu-Cl)(2)(eta(5)-Cp*)(2)] does not react with the germylenes (1a and 1b). When the reactions of 1a and 1b are carried out with [Cp*TaCl4], the reaction led to decomposition. The reaction of 1a or 1b with TaCl5 yielded the transmetallated products [(Dipp)NCMeCHCORTaCl4] (4a: R = Me, 4b: R = Ph) with the extrusion of GeCl2. Our theoretical studies show that for, the insertion of TaCl5 to 1a and the formation of 4a with concomitant elimination of GeCl2 is energetically favourable. Extrusion of SnCl2 is also observed when the corresponding stannylene, [(Dipp)NCMeCHCOMeSnCl] was reacted with TaCl5. All these compounds have been characterized by H-1 and C-13 NMR spectroscopy, elemental analysis and the constitution of compounds 1b, 3b, and 4a were confirmed by single-crystal X-ray crystallography. (C) 2020 Elsevier B.V. All rights reserved.

}, keywords = {Adduct formation, Germylenes, Iridium, Ketoiminate, Tantalum, Transmetallation}, issn = {0022-328X}, doi = {10.1016/j.jorganchem.2020.121142}, author = {Raghavendra, Beesam and Bakthavachalam, K. and Das, Tamal and Roisnel, Thierry and Sen, Sakya S. and Vanka, Kumar and Ghosh, Sundargopal} }