Nanoscience is a new area of science that has generated excitement worldwide. Nanomaterials are being developed to address some of the world’s biggest challenges, including: clean, affordable energy; stronger, lighter, more durable materials; medical devices and drugs to detect and treat diseases; sensors to detect harmful chemical or biological agents; lighting that uses a fraction of the energy; low-cost filters to provide clean drinking water. We work on molecular gold nanoparticles (<2nm) that have precise number of gold atoms and ligands. Commercialization of nanomaterials and design of nanoengineered products will require: understanding of the fundamental properties; controlled synthetic and processing conditions. In my research group, we work on synthesis and characterization (mass spectrometry, NMR, optical spectroscopy) of these molecular gold nanoparticles.
Gold Nanoclusters - Assistant Professor @ OleMiss
xx. “(AuAg)144(SR)60 alloy nanomolecules” Chanaka Kumara and Amala Dass, Nanoscale 2011, 3, 3064-3067.
xx. “Size Exclusion Chromatography for Semi-Preparative Scale Separation of Au38(SR)24 and Au40(SR)24 and larger clusters” Stefan Knoppe, Julien Boudon, Igor Dolamic, Amala Dass, and Thomas Burgi, Anal. Chem. 2011, 83, 5056-5061.
xx. “Au36(SPh)23 Nanomolecules” Praneeth Reddy Nimmala and Amala Dass, J. Am. Chem. Soc. 2011, 133, 9175–9177.
30. “Ligand Exchange Reactions on Au38 and Au40 Clusters: A Combined Circular Dichroism and Mass Spectrometry Study” S. Knoppe, A. C. Dharmaratne, E. Schreiner, A. Dass, and T. Burgi, J. Am. Chem. Soc. 2010, 132, 16783–16789.
29. “Ion Mobility Mass Spectrometry of Au25(SCH2CH2Ph)18 Nanoclusters” L. A. Angel, L. T. Majors, A. C. Dharmaratne, A. Dass, ACS Nano 2010, 4, 4691-4700.
28. “Surfactant-free Synthesis of Ultra-small Gold Nanoclusters” S. Reilly, T. Krick, A. Dass, J. Phys. Chem. C. 2010, 144, 741-745.
27. “Solvent-Dependent Stability of Monolayer-Protected Au38 Clusters” O. Toikkanen, S. Carlsson, A. Dass, G. Ronnholm, N. Kalkkinen, B. M. Quinn, J. Phys. Chem. Lett. 2010, 1, 32–37.
26. “Nanocluster Size Evolution Studied by Mass Spectrometry in Room Temperature Au25(SR)18 Synthesis” A. C. Dharmaratne, T. Krick, A. Dass, J. Am. Chem. Soc. 2009, 131, 13604–13605.
25. “Mass Spectrometric Identification of Au68(SR)34 Molecular Gold Nanoclusters with 34-Electron Shell Closing” A. Dass, J. Am. Chem. Soc. 2009, 131, 11666-11667.
24. “Mass Spectrometry of Small Bimetal Monolayer-Protected Clusters” C. A. Fields-Zinna, M. C. Crowe, A. Dass, J. E. F. Weaver and R. W. Murray, Langmuir2009, 25, 7704–7710.
23. “Mass Spectrometrically Detected Statistical Aspects of Ligand Populations in Mixed Monolayer Au25L18 Nanoparticles” A. Dass, K. Holt, J. Parker, S. Feldberg, R. W. Murray, J. Phys. Chem. C.2008, 112, 20276-20283.
22. “Fast Atom Bombardment Mass Spectrometry of Au25(SCH2CH2Ph)18” A. Dass, G. Dubay, R. W. Murray, Anal. Chem.2008, 80, 6845-6549.
21. “Nanoparticle MALDI-TOF Mass Spectrometry without Fragmentation: Au25(SCH2CH2Ph)18 and Mixed Monolayer Au25(SCH2CH2Ph)18-x(L)x”, A. Dass, A. Stevenson, G. R. Dubay, J. B. Tracy, R. W. Murray, J. Am. Chem. Soc.2008, 130, 5940-5946.
20. “Crystal structure of the Gold Nanoparticle [N(C8H17)4] [Au25SCH2CH2Ph)18]” M. Heaven, A. Dass, K. Holt, P. White, R. W. Murray, J. Am. Chem. Soc.2008, 130, 3754-3755.
19. “Electrospray Ionization Mass Spectrometry of Uniform and Mixed Monolayer Nanoparticles: Au25[S(CH2)2Ph]18 and Au25[S(CH2)2Ph]18-x(SR)x”, J. B. Tracy, M. C. Crowe, J. F. Parker, O. Hampe, C. A. Fields-Zinna, A. Dass, R. W. Murray. J. Am. Chem. Soc. 2007, 129, 16209-16215.
18. “Gold Nanoparticles with Perfluorothiolate Ligands”, A. Dass, R. Gao, J. B. Tracy, R. Balasubramanian, A. D. Douglas, R. W. Murray, Langmuir 2008, 24, 310-315.
17. “Demonstration of the Elusive Concentration-Gradient Paramagnetic Force,” N. Leventis and A. Dass; J. Am. Chem. Soc. 2005, 127, 4988-4989.
16. “Magnetic Field Effects on the Open Circuit Potential of Ferromagnetic Electrodes in Corroding Solutions,” A. Dass, J. A. Counsil, X. Gao and N. Leventis; J. Phys. Chem. B.2005, 109, 11065-11073.
15. “Mass transfer effects on the electropolymerization current efficiency of 3-methylthiophene in the magnetic field”, N. Leventis, A. Dass, N. Chandrasekaran; J. Solid State Electrochem.2006, 11, 727-735.
14. “Funnel-like flow generated electrochemically in paramagnetic media by the two paramagnetic body forces”, N. Leventis, N. Chandrasekaran, A. Dass, X. Gao, ECS Transactions2008, 13, 25-31.
13. “Protection of 2-(3-Thienyl)ethanol with 3-Thienylacetic Acid and Hard Cross-linked conducting films by Electropolymerization of the Ester”, A. Dass, S. Mulik, C. Sotiriou-Leventis, N. Leventis; Synth. Met.2006, 156, 966-972.
12. “Non-additive voltammetric currents from multicomponent systems of redox-active substances; A. Dass and N. Leventis Electrochimica Acta.2005, 50, 4134-4139.
11. “Multiple Substitution Effects and Non-Linear Free Energy Relationships in the Electrochemical Reduction of the N,N’-Dibenzylviologen and the 4-Benzoyl-N-benzylpyridinium Cation,” N. Leventis, M. A. B. Meador, G. Zhang, A. Dass and C. Sotiriou-Leventis; J. Phys. Chem. B.2004, 108, 11228-11235.
10. “Stresses at the interface of micro with nano” N. Leventis, S. Mulik, X. Wang, A. Dass, C Sotiriou-Leventis, H. Lu, J. Am. Chem. Soc.2007, 129, 10660-10661.
9. “Polymer nano-encapsulation of templated mesoporous silica monoliths with improved mechanical properties,” N. Leventis, S. Mulik, X. Wang, A. Dass, V. U. Patil, C. Sotiriou-Leventis, H. Lu, G. Churu, A. Capecelatro. J. Non-Cryst. Solids2008, 354, 632-644.
8. “Polymer nanoencapsulated rare earth aerogels: chemically complex but stoichiometrically similar core-shell superstructures with skeletal properties of pure compounds” N. Leventis, P. Vassilaras, E. Fabrizio, A. Dass, J. Mater. Chem. 2007, 17, 1502-1508
7. “Hydrophobic monolithic aerogels by nanocasting polystyrene on amine-modified silica,” U. F. Ilhan, E. F. Fabrizio, L. McCorkle, D. A. Scheiman, A. Dass, A. Palczer, M. B. Meader, J. C. Johnston and N. Leventis, J. Mater. Chem., 2006, 16, 3046-3054.
6. “Chemical, Physical and Mechanical Characterization of Isocyanate-Crosslinked Amine-Modified Silica Aerogels,” A. Katti, N. Shimpi, S. Roy, H. Lu, E. F. Fabrizio, A. Dass, L. A. Capadona and N. Leventis, Chem. Mater. 2006, 18, 285-296.
5. “Cross-linking Amine-Modified Silica Aerogels with Epoxies: Mechanically Strong Lightweight Porous Materials,” M. A. B. Meador, E. F. Fabrizio, F. Ilhan, A. Dass, G. Zhang, P. Vassilaras, J.C. Johnston, and N. Leventis; Chem. Mater. 2005, 17, 1085-1098.
4. “Isocyanate Cross-Linked Silica Aerogel Monoliths: Preparation and Characterization,”G. Zhang, A. Dass, A.-M. M. Rawashdeh, J. Thomas, J. A. Counsil, C. Sotiriou-Leventis, E. F. Fabrizio, F. Ilhan, P. Vassilaras, D. A. Scheiman, L. McCorkle, A. Palczer, J. Chris Johnston, M. A. B. Meador and N. Leventis J. Non-Cryst. Solids, (ISA-7), 2004, 350, 152-164.
3. “Synthesis and Near IR Photoluminescence of Os(II) Bis(2,2’-bipyridine) (3,8-Diarylethynyl 1,10-phenanthroline) complexes. Study of the anomalous behavior of the 3,8-Di(4-nitrophenylethynyl)- Derivative,” J. Yang, A. Dass, C. Sotiriou-Leventis and N. Leventis; Inorg. Chim. Acta 2005, 358, 389-395.
2. “Arylethynyl Substituted 9,10-Anthraquinones: Tunable Stokes Shifts by Substitution and Solvent Polarity,” J. Yang, A. Dass, A.-M. M. Rawashdeh, C. Sotiriou-Leventis, D. S. Tyson, J. D. Kinder and N. Leventis; Chem. Mater. 2004, 16, 3457-3468.
1.. “Synthesis and Characterization of Ru(II) Tris(1,10-phenanthroline)-Electron Acceptor Dyads Incorporating the 4-Benzoyl-N-methylpyridinium Cation or N-Benzyl-N´-methylviologen: Improving the Dynamic Range, Sensitivity and Response Time of Sol-Gel Based Optical Oxygen Sensors,” N. Leventis, A.-M. M. Rawashdeh, I. A. Elder, J. Yang, A. Dass and C. Sotiriou-Leventis, Chem. Mater.2004, 16, 1493-1506.