Details of CH4202 (Spring 2025)
| Level: 4 | Type: Theory | Credits: 4.0 |
| Course Code | Course Name | Instructor(s) |
|---|---|---|
| CH4202 | Symmetry in Chemistry | Debasis Koley |
| Syllabus |
|---|
| A: Bonding in organic and inorganic chemistry (13 Classes)
Construction of qualitative MO diagram using the concepts of SALC and Projection operator in followings: (i) SALC and MO diagram in homo- and hetero-nuclear diatomic molecules (H2, N2, O2, CO, NO ) (ii) SALC and MO diagram in AHn (A=second-row atom) (BeH2, BH3, CH4, NH3, H2O, HF), pendant atom (iii) SALC and MO diagram in Mxn, e.g., alpha-bonding in BF3, XeF4, BrF5, pi-bonding in CO2, SF6 (iv) SALC and MO diagram in pi-electronic systems. pi-approximation (carbonate ion, transbutadiene, cyclobutadiene, etc.), pi-MOs of carbocyclic systems (e.g., benzene, naphthalene); Hckel MO theory. B: Bonding in transition-metal complexes (7 Classes) Transformation properties of Atomic orbitals. Frontier orbitals. (i) LCAO-MO for alpha-bonding in Oh, Td, D4h and other geometries. (ii) LCAO-MO for pi-bonding in Oh, Td, D4h and other geometries. (iii) LCAO-MO in cage and cluster compounds (B6H62, metal carbonyl) (iv) LCAO-MO in sandwich complexes (ferrocene, dibenzenechromium) C: Molecular vibration (10 Classes) Symmetry species of normal vibrations ( ) in polyatomic molecules in various geometries. Selection rules in IR and Raman spectroscopy, Polarization, Overtones, combination bands and Hot bands , Stretching and bending mode analysis, Fermi resonance, Rule of mutual exclusion. Using correlation tables with vibrational spectra (CH4 and CH3D). Examples: (H2O, CO2, XeF4, BCl3, NH3, B2H6, C2H4, CH4, SF6, C6H6, etc.) D: Electronic Spectroscopy (7 Classes) Molecular term symbols (B2, N2, O2, etc) Electric dipole transition. Orbital and spin selection rule. Frank-Condon factor, Vibronic selection rule, Relaxation in selection rule. Magnetic dipole selection rules, single-photon and two-photon spectroscopy, forbidden transition, Laporte selection rule Ligand field theory of transition-metal complexes: electronic structure of free atoms and ions, Splitting of levels and terms in various chemical environment (Oh, Td), weak fields and strong fields, correlation table, Jahn-Teller effect, Orgel diagram, correlation diagram, method of descending symmetry, non-crossing rule. Hole formalism, Tanabe-Sugano diagram, Chargetransfer spectra. E: Photochemistry and conservation of orbital symmetry (3 Classes) Woodward Hoffmann rule, Frontier orbitals, Symmetry State Correlation, Electrocyclic reaction, Cycloaddition reaction (ethylene dimerization), Sigmatropic rearrangement |
| References |
|---|
| References:
1. Symmetry and Structure, by S. F. A. Kettle, JohnWiley & Sons. NY. 2. Molecular Symmetry and Group Theory, by R. L. Carter, JohnWiley & Sons. NY. 3. Molecular Symmetry, by D. J. Willock, JohnWiley & Sons. NY. 4. Chemical Applications of Group Theory, by F. A. Cotton, JohnWiley & Sons. NY. 5. Group Theory and Chemistry, by D. M. Bishop, Dover Publication. NY. 6. Symmetry and Group Theory in Chemistry, by M. Ladd, Horwood Publishing. Chichester |
Course Credit Options
| Sl. No. | Programme | Semester No | Course Choice |
|---|---|---|---|
| 1 | IP | 2 | Not Allowed |
| 2 | IP | 4 | Not Allowed |
| 3 | IP | 6 | Not Allowed |
| 4 | MP | 2 | Not Allowed |
| 5 | MP | 4 | Elective |
| 6 | MR | 2 | Not Allowed |
| 7 | MR | 4 | Not Allowed |
| 8 | MS | 10 | Not Allowed |
| 9 | MS | 4 | Not Allowed |
| 10 | MS | 6 | Not Allowed |
| 11 | MS | 8 | Core |
| 12 | RS | 1 | Elective |
| 13 | RS | 2 | Elective |