New Chemistry of Gold

Transcription

1 Established in 1959 New Chemistry of Gold T. Pradeep Department of Chemistry Indian Institute of Technology Madras Chennai Quantum clusters: Au 25, Au 23, Au 22, Au 8, Ag 8, Ag 9, Ag 25 Anna University, March 7, 2011

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4 Hardcover: 274 pages Publisher: Elsevier Science Ltd (June 1978) Language: English ISBN-10: ISBN-13: Gold Chemistry ISBN: Hardcover 908 pages March 1999

5 Gold catalysis Number of papers published per year after the discovery of gold catalysis.

6 5000 Numbe rof publication in gold nanoparticle Publications per year as on December 31, 2010 With the key words, gold and nanoparticle* Year

7 Monolayer Protected Metal Nanoparticles Monolayer Protected Clusters (MPCs) N. Sandhyarani and T. Pradeep, Int. Rev. Phys. Chem. 2003

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10 A B 1 nm 1 nm 4.8 nm 7.8 nm 0.1 µm 20 nm E. S. Shibu et al. Adv. Mater. 2008; Nano Res. 2009; Chem. Mater. 2009

11 Fluorescent superlattices E. S. Shibu et al, Adv. Mater. 2008; Nano Res. 2008, Chem. Mater.; 2009

12 Manometer Rotary pump to gas source Power supply A B C Keithley multimeter ma D c b a 1 cm 10 µm E. S. Shibu et al. Nanoscale (2011). 12

13 Current (ma) 3.5x10-6 A 1. 5 volt 100 torr 3.0x x O Ar -----N CO 2 Current (ma) -----O volt 500 torr 3.6x Ar -----N CO 2 3.0x x10-6 B 1.8x x Time (sec) 1.2x Time (sec) Current (ma) 2.4x x x10-6 Current Raman Intensity C Raman Intensity a d l a= particle diameter d= gas molecule diameter l= thickness of monolayer z D Time (sec) 23 March 2011 E. S. Shibu, IIT M 13

14 P. R. Sajanlalal and T. Pradeep Nano Res. 2009; JPC C 2009; 2010

15 A B Intensity Au Ag 1 µm 1 µm AuAg C D Distance (nm) 500 nm 500 nm AuAg

16 Region-specific SERS activity ecreasing or er of SERS ac vity u g s u s u Pt s 1 µm 5 µm AuAg EDAX image of Au/Ag MF Raman shift (cm -1 ) 0.8 µm Raman image of Au/Ag MF SERS intensity is higher at the tip compared to the body of the stem. Au/Ag mesoflowers show high SERS activity than Au mesoflowers. show ten-fold increase in the SERS enhancement factor than Au mesoflowers. capable of detecting biomolecules and explosives at very low concentrations. P. R. Sajanlal and T. Pradeep, Langmuir, 26 (2010)

17 50 nm Faraday s gold preserved in Royal Institution. From the site,

18 they are simply cases of pure gold in a divided state; yet I have come to that conclusion, and believe that the differentlycoloured fluids and particles are quite analogous. Experimental Relations of Gold (and Other Metals) to Light, M. Faraday, Philos. Trans. R. Soc. London, 1857, 147, 145

19 Gustav Mie ( ) Surface plasmons 1905 By changing size 1940 Mie G. Beiträge zur Optik trüber Medien speziell kolloidaler Goldlösungen (contributions to the optics of diffuse media, especially colloid metal solutions). Ann Phys 1908;25: This paper, including an English translation, as well as other historic papers on light scattering and absorption can be found at

20 Gas phase cluster spectroscopy Mass spectra of positively charged Ar, Kr, Xe clusters, W. Miehle, O. Kandler, T. Leisner, and O. Echt. (1989) J. Chem. Phys., 91, 5940.

21 Laser desorption mass spectrometry Smalley et al. Nature 1985

22 Supported gold clusters in catalysis Schematic representation for CO oxidation pathways over Au/TiO2. M. Haruta. When Gold Is Not Noble: Catalysis by Nanoparticles. Chem. Rec. 2003, 3, 75.

23 Magic clusters From Gunter Schmidt, Chem. Soc. Rev. 2008, 37,

24 Gold clusters Au 13 Au 55 [Au 13 (PPhMe 2 ) 10 C1 2 ] 3+ Au 55 [P(C 6 H 5 ) 3 ] 12 Cl 6 - a gold cluster of unusual size, Schmid, G.; Pfeil, R.; Boese, R.; Brandermann, F.; Meyer, S.; Calis, G. H. M.; Van der Velden.; Jan W. A. Chemische Berichte 1981, 114, Synthesis and x-ray structural characterization of the centered icosahedral gold cluster compound [ Au 13 (PMe 2 Ph) 10 Cl 2 ](PF 6 ) 3 ; the realization of a theoretical prediction, Briant, C. E.; Theobald, B. R. C.; White, J. W.; Bell, L. K.; Mingos, D. M. P.; Welch, A. J. Chem. Commun. 1981, 5, 201. Synthesis of water-soluble undecagold cluster compounds of potential importance in electron microscopic and other studies in biological systems, Bartlett, P. A.; Bauer, B.; Singer, S. J. Am. Chem. Soc. 1978, 100, 5085.

25 Molecular Clusters 28 kda Alkanethiolate-Protected Au Clusters Give Analogous Solution Electrochemistry and STM Coulomb Staircases, Ingram, R. S.; Hostetler, M. J.; Murray, R. W.; Schaaff, T. G.; Khoury, J.; Whetten, R. L.; Bigioni, T. P.; Guthrie, D. K.; First, P. N. J. Am. Chem. Soc. 1997, 119, Isolation of Smaller Nanocrystal Au Molecules: Robust Quantum Effects in Optical Spectra, Schaaff, T. G.; Shafigullin, M. N.; Khoury, J. T.; Vezmar, I.; Whetten, R. L.; Cullen, W. G.; First, P. N.; Gutierrez-Wing, C.; Ascensio, J.; Jose-Yacaman, M. J. J. Phys. Chem. B 1997, 101, Optical Absorption Spectra of Nanocrystal Gold Molecules, Alvarez, M. M.; Khoury, J. T.; Schaaff, T. G.; Shafigullin, M. N.; Vezmar, I.; Whetten, R. L. J. Phys. Chem. B 1997, 101, 3706.

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27 How to make them?