無機光譜化學 Inorganic Spectroscopic Chemistry Time : Thursday 9: :45Classroom : 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) spectroscopy Cotton Chapter 9 Ebsworth/Rankin/Cradock Chapter 6 Brisdon Chapter 4 ˙ IR/Raman (vibrational) spectroscopy Cotton Chapter 10 Ebsworth/Rankin/Cradock Chapter 5 Brisdon Chapter 2 ˙ Mass Spectrometry Ebsworth/Rankin/Cradock Chapter 9 Drago Chapter 16 Brisdon Chapter 5 ˙ NMR Spectroscopy Ebsworth/Rankin/Cradock Chapter 2 Drago Chapter 7, 8 Brisdon Chapter 3 ˙ ESR Spectroscopy Ebsworth/Rankin/Cradock Chapter 3 Drago Chapter 9 Brisdon Chapter 3 Grade :Mid-term 40% Final 40% Quiz 20%

2 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?

3 Some physical techniques in determining structure Fingerprint Group present Molecular symmetry Bond lengths and angles Electronic structure

4 excited state electronic transition vibrational transition rotational transition ground state E = E electronic + E vibration + E rotation + E translation population distribution N upper ——— = exp(-  E/kT) k =1.381  J/K N lower radiation E = h  = hc/ unit 1 nm = m 1 cm -1 = J/mol = 2.86 cal/mol 1 eV = J/mol = cal/mol

5 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) ESR (solution) rotational spectroscopy (gas) vibrational spectroscopy (gas) electronic spectroscopy (solution) Mössbauer spectroscopy (solid) Nuclear energies Chemical energies Molecular energies Spin energies XRF ∣ Electronic ∣ ∣ Rotational ∣ Mössbauer XPS UPS ∣ Vibrational ∣ ESR NMR NQR GED XRD

6 glossary of spectroscopic and structural techniques

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15 Symmetry – group theory symmetry operation identityE inversioni reflection  rotationC rotation and reflectionS point group character table ex. What is the point group for [PtCl 4 ] 2- ? Cl Cl –– Pt –– Cl Cl symmetry element: E, C 4, C 2, i,  h,  v,  d, S 4 point group: D 4h

16 character table of D 4h