Post on 20-Dec-2015
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6205334 無機光譜化學Inorganic Spectroscopic Chemistry
Time : Thursday 9:00 - 11:45 Classroom : Chem 430 Textbooks : ˙ F.A. Cotton “Chemical Applications of Group
Theory, 3rd ed.”, 1990, Wiley.˙ E.A.V. Ebsworth, D.W.H. Rankin, S. Cradock “Structural Methods in Inorganic Chemistry, 2nd ed.”, 1991, CRC.˙ R.S. Drago “Physical Methods for Chemists, 2nd ed.”, 1992, Saunders.˙ A.K. Brisdon “Inorganic Spectroscopic Methods” 1998, Oxford.
Contents : ˙ UV-visible (electronic) spectroscopyCotton Chapter 9Ebsworth/Rankin/Cradock Chapter 6Brisdon Chapter 4
˙ IR/Raman (vibrational) spectroscopyCotton Chapter 10Ebsworth/Rankin/Cradock Chapter 5Brisdon Chapter 2
˙ Mass SpectrometryEbsworth/Rankin/Cradock Chapter 9Drago Chapter 16Brisdon Chapter 5
˙ NMR SpectroscopyEbsworth/Rankin/Cradock Chapter 2Drago Chapter 7, 8Brisdon Chapter 3
˙ ESR SpectroscopyEbsworth/Rankin/Cradock Chapter 3Drago Chapter 9Brisdon Chapter 3
Grade : Mid-term 40% Final 40% Quiz 20%
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Introduction
Determining structure
˙ contain any known compound?
˙ is it pure?
˙ what functional group it contains?
˙ what is its composition and molecular
weight?
˙ how the functional groups linked together?
˙ what is molecular symmetry?
˙ what are the bond lengths and bond angles?
˙ what is its electronic structure?
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Some physical techniques in determining structure
Fingerprint
Group present
Molecular symmetry
Bond lengths and angles
Electronicstructure
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excited state
electronic transition
vibrational transition rotational transition
ground state
E = Eelectronic + Evibration + Erotation + Etranslation
population distribution
Nupper ——— = exp(-E/kT) k =1.381 10-23 J/K Nlower
radiation E = h = hc/
unit 1 nm = 10-9 m 1 cm-1 = 11.98 J/mol = 2.86 cal/mol 1 eV = 96500 J/mol = 23060 cal/mol
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spectrum of electromagnetic radiation
timescales associated with some spectroscopic techniques
Energy of excited state Typical relaxation Typical
Technique (Hz) time (seconds) linewidth (Hz)
NMR (solution) 108 10 10-1
ESR (solution) 1010 10-5 105
rotationalspectroscopy (gas) 1011 10-4 104
vibrationalspectroscopy (gas) 1014 10-8 108
electronic spectroscopy (solution) 1016 10-15 1015
Mössbauerspectroscopy (solid) 1019 10-8 108
Nuclear energies Chemical energies Molecular energies Spin energies XRF Electronic∣ ∣ ∣ Rotational ∣Mössbauer XPS UPS Vibrational ∣ ∣ ESR NMR NQR GED XRD
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Symmetry – group theorysymmetry operation
identity E
inversion i
reflection rotation C
rotation and reflection S
point group
character table
ex. What is the point group for [PtCl4]2-?
Cl
Cl –– Pt –– Cl
Cl
symmetry element: E, C4, C2, i, h, v, d, S4
point group: D4h