Calendar of Events
Reactions between nanoparticles
Institute of Nanotechnology
Bldg. 640 Seminar room 0-167
Talk given by
Prof. T. Pradeep
Atomically precise clusters of noble metals is an expanding research theme. An emerging aspect of their science will be the topic of discussion in this seminar. Atom and structure conserving chemical reactions between two atomically precise archetypal nanoparticles[2,3], Ag25(SR)18 and Au25(SR)18, will be used to illustrate this science. Despite their geometric robustness and electronic stability, reactions between them in solution produce alloys, AgmAun(SR)18 (m+n=25), keeping their M25(SR)18 composition, structure and topology intact. We have shown that a mixture of Ag25(SR)18 and Au25(SR)18 can be transformed to any arbitrary alloy composition, AgmAun(SR)18 (n=1–24), merely by controlling the reactant compositions.
We captured one of the earliest events of the process, namely the formation of the dianionic adduct, [Ag25Au25(SR)36]2-, by electrospray ionization mass spectrometry. Molecular docking simulations and density functional theory (DFT) calculations have suggested that metal atom exchanges occurred through the formation of an adduct between the two clusters. DFT calculations further confirmed that metal atom exchanges were thermodynamically feasible. Such isomorphous transformations between nanoparticles imply that microscopic pieces of matter can be transformed completely to chemically different entities, preserving their structures, at least in the nanometric regime. The capability envisioned here is important for sustainable development. A more recent development is the finding that such chemistry distinguishes the geometric shell structure of clusters.
 I. Chakraborty and T. Pradeep, Chem. Rev., 2017, In Press.
 M. W. Heaven, A. Dass, P. S. White, K. M. Holt, and R. W. Murray J. Am. Chem. Soc., 2008, 130, 3754-3755.
 C. P. Joshi, M. S. Bootharaju, M. J. Alhilaly, and O. M. Bakr J. Am. Chem. Soc., 2015, 137, 11578−11581.
 K. R. Krishnadas, A. Baksi, A. Ghosh, G. Natarajan and T. Pradeep Nat. Commun., 2016, 7, 13447 (DOI: 10.1038/ncomms13447).
 K. R. Krishnadas; A. Baksi; A. Ghosh, G. Natarajan and T. Pradeep, ACS Nano, 2017, In Press.
Prof. T. Pradeep
Indian Institute of Technology Madras
Pradeep Research Group
Prof. Dr.-Ing. Horst Hahn
Institute of Nanotechnology (INT)
Karlsruhe Institute of Technology (KIT)
Mail:horst hahn∂kit edu
Interested / Everyone