nano chemistry
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chemistryTRANSCRIPT
Scott Group: NanochemistrySemiconducting CdSe Quantum Dots
Colour changes with Size!
4 nm = 0.000004 mm
Scott Group: NanochemistrySolutions of Gold Nanoparticles also change colour with Size!
Plasmon Band @ ~ 520 nm
• Nanochemistry has old roots• Colloidal Au used in Ancient Roman times • Described by Faraday in 1857 Lycurgus Cup, 300 A.D.
Bimetallic Au-Ag nanoparticleshttp://www.thebritishmuseum.ac.uk
Scott Group: NanochemistryMetal Nanoparticles
Chemistry changes with Size!
Au Au
CO CO2
CO CO2
X See, for example:Valden et al., Science 1998,281, 1647.Scott et al., J. Phys. Chem. B 2005, 109, 692.
Gold Nanoparticles
A
Mita Dasog
• Size control possible by adjusting ratio of HAuCl4 : alkanethiol• Monodispersity can be improved by fractional precipitation• Brust et al., Chem. Commun., 1994, 801.
3.9 ± 0.6 nm
Gold Nanoparticles
A
Mita Dasog
• Size control possible by adjusting ratio of HAuCl4 : alkanethiol• Monodispersity can be improved by fractional precipitation• Brust et al., Chem. Commun., 1994, 801.
Au
S
S
SS
SS
HAuCl4C12H25SH
NaBH4
SO3
Au
S-S
SS
S
Air Exposure SS
Au
S
S
SS
SSSSS
S
SS
S
S
SS
S
S
S-SSO3
B
3.9 ± 0.6 nm 6.2 ± 1.0 nm
Gold Nanoparticles Mita Dasog
• Particle aggregation co-exists with alkanesulfonate formation
• Oxidation of thiols on Au surface by O2!
As synthesized
Air oxidized
Ionic Liquids for Materials Synthesis
Nicole DehmPriyabrat Dash
NN
PF6
AuN N
N
NN
N
N
N
• Liquids at Room Temp. • No vapour pressure• Low surface tension
200 nm
TiCl4
Self-Assembly Hydrolysis
TiO2
One pot synthesis of titania-Au catalysts!
Amine-stabilized AuNanoparticles
Continuing Work
Catalysis with Gold Nanoparticles in Solution
Nicole Dehm
OH
2 atom % Au:PVP300 mol% K2CO3
H2O, air, 300K
O
OH
Benzyl Alcohol Benzoic Acid
Tsunoyama et al., J. Am. Chem. Soc. 2005, 127, 9374.
Barcode Nanowires for Chemical Sensing
Mintang LiuNicewarner-Pena, et al., Science 2001, 294, 137.
Biophysicochemical Properties of Nanoparticles (Bernie Kraatz, Matthew Paige)
Zahid Islam
R R
R
R
R
RR
RR
R
R
R
RR
hv
FRET
emission
R R = NR3+, SO4
-, etc.
How do nanoparticles interact with Lipid membranes?
How does one detect single nanoparticle-biomolecule interactions?
How strongly nanoparticles associatewith biomolecules?