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SUMMARY:Chiral Inorganic Nanoparticles - Prof. Nick Kotov (University of M
 ichigan\, Depts. of Chem. Eng. and Materials Science)
DTSTART:20170515T150000Z
DTEND:20170515T163000Z
UID:TALK72575@talks.cam.ac.uk
CONTACT:Stoyan Smoukov
DESCRIPTION:One of the rapidly expanding fields of inorganic materials is 
 chiral inorganic nanostructures (CNI).  This talk will cover both experime
 nt and theory of CNI starting with the origin and multiple components of m
 irror asymmetry of individual NPs and their assemblies.  Differences and s
 imilarities with chiral strctures known from other fields of chemistry wil
 l  be discussed as well.  \n 	Developement of the field of CNI started fro
 m the observation of strong circular dichroism for single nanoparticles (N
 Ps) and their assemblies. It is currently being expanded to sophisticated 
 constructs involving nanostructures from metals\, semiconductors\, ceramic
 s\, and nanocarbons. Besides the well-established chirality transfer from 
 bioorganic molecules extensively used in organic chemistry\, other methods
  to impart handedness to nanoscale matter specific to inorganic materials 
 were discovered. They  include 3D lithography\, multiphoton chirality tran
 sfer\, polarization effects in nanoscale assemblies\, and others. Multiple
  chiral geometries were observed with characteristic scales from ångströ
 ms  to microns.  For many of them uniquely strong polarization rotation an
 d high values of chiral anisotropy factors was observed.   It will be show
 n that\, the high values of chiroptical activity found in CNI are due to s
 trong resonances of incident electromagnetic radiation with plasmonic and 
 excitonic states typical for metals and semiconductors typical for inorgan
 ic matter.  \nAt the same time\, distinct similarities of CNI with chiral 
 supramolecular and biological systems also emerged. They can be seen in th
 e synthesis and separation methods\, chemical properties of individual NPs
 \, geometries of the NP assemblies\, and interactions with biological coun
 terparts. For instance\, semiconductor NPs modified by L- and D-aminoacids
  spontaneously assemble into biosimilar helices with near unity enantiomer
 ic excess\, *e.g. 98%*. The analysis of these similarities with known biol
 ogical\, supramolecular\, and liquid crystalline materials help us underst
 and in greater depth the role of chiral asymmetry in Nature and accelerate
  the development of technologies based on chiroplasmonic and chiroexcitoni
 c effects.  Technological prospects of chiral inorganic materials with cur
 rent front runners being biosensing\, chiral catalysis\, and chiral photon
 ics will be presented.  \n\n*Relevant References*:\n#[1]	Chen\, W. et al. 
 Nanoparticle Superstructures Made by Polymerase Chain Reaction: Collective
  Interactions of Nanoparticles and a New Principle for Chiral Materials. _
 Nano Lett._ *2009*\, 9(5)\, 2153. \n#[2]	Kotov\, N.A. Inorganic Nanopartic
 les as Protein Mimics _Science_\, *2010*\, 330\, 188.\n#[3]	Ma\, M.\; et a
 l. Attomolar DNA Detection with Chiral Nanorod Assemblies. _Nature Comm._ 
 *2013*\, 4\, 2689.\n#[4]	Yan\, W.\; et al.  Self-Assembly of Chiral Nanopa
 rticle Pyramids with Strong R/S Optical Activity. _J. Am. Chem. Soc._ *201
 2*\, 134(36)\, 15114.\n#[5]	Srivastava\, S.\; et al Light-Controlled Self-
 Assembly of Semiconductor Nanoparticles into Twisted Ribbons. _Science_ *2
 010*\, 327\, 1355–1359.\n#[6]	J.Yeom\, et al Chiral Templating of Self-A
 ssembling Nanostructures by Circularly Polarized Light\, _Nature Mater._ *
 2015*\, 14\, 66.\n#[7]	W. Feng\, et al Assembly of Mesoscale Helices with 
 Near Unity Enantiomeric Excess and Light-Matter Interactions for Chiral Se
 miconductors\, _Science Advances_\, *2017*\, 3(3) e1601159. \n\n*About the
  speaker*:\nProf. Kotov is a pioneer in the synthesis of nanoparticles and
  their self-assembly. He is a Fellow of the Royal Society of Chemistry\, T
 hompson Reuters Highly Cited Researcher\, MRS Fellow\, and the MRS Medal w
 inner\, amongst numerous other awards.\n\n
LOCATION:Goldsmiths 1 Lecture Theatre\, Materials Science and Metallurgy B
 uilding
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