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1. seminar topic: “TANABE SUGANO DIAGRAMS FOR d 2 AND d 8 IONS “. BY HARINI.C. Reg. No.: P11AZ23S104048 I MSC .II SEM DOS & R in organic chemistry Tumkur university , Tumkur SUBMITTED TO The coordinator Dr. SURESH D DOS & R in organic chemistry Tumkur university , Tumkur under the guidance of Dr. PRIYARANI DOS & R in organic chemsitry Tumkur university , Tumkur 1 T UMKUR UNIVER S ITY Department of Studies and Research in Organic Chemistry Tumkur University Tumkuru - 572103

2. CONTENTS Introduction About tanabe-sugano diagrams. Tanabe- sugano diagrams of d 2 & d 8 ions Conclusions. Reference. 2

3. INTRODUCTION The simple orgel energy level diagrams are useful for interpreting spectra but there diagram are two important limitations. 1.They treat only the high spin case. 2.They are only useful for spin allowed transitions. Tanabe- sugano diagram used in co-ordination chemistry to predict absorption in the visible and I-R electromagnetic spectrum of co-ordination compounds. It can be used for both high spin and low spin complexes. 3

4. TANABE-SUGANO DIAGRAMS Tanabe – sugano diagram are commonly used for interpretation of spectra including weak and strong complexes of ions. . Tanabe- sugano diagrams are similar to orgel diagrams but they differ in several ways. 1.Ground state is always taken as the abscissa (horizontal axis) and provides a constant reference point ,the other energy states are plotted relative to this. 2.Low spin terms i.e states where the spin multiplicity is lower than the ground state are included. 3.In order to make diagrams general for different metal ions with the same electronic configuration and to allow for different ligands both of which effect D and B (crystal field splitting an racah’s parameter) the axis are plotted in units of energy E/B and Dq /B. 4

5. DEFINITION: The Tanabe – sugano diagram is a plot of orbital energy as a function of the Racah parameter(E/B) V/S Δ o /B . E/B Δ o /B The x-axis of the Tanabe- sugano diagram expressed in terms of the ligand field splitting parameter, Δ , or Dq (for" differential of quanta“),divided by the Racah parameter B. The y-axis is in term of energy ,E, also scaled by B. Racah parameter: Describe the various aspect of the inter electronic repulsion. B- is the most important Racah parameter to explain the Tanabe – sugano parameter . Typically for free ion B=1000cm -1 5

6. Configuration Term symbol d 2 ,d 8 3 F, 3 P, 1 G, 1 D, 1 S L Term Term splitting in tetrahedral field Term splitting in octahedral field S A 1 A 1g 1 P T 1 T 1g 2 D E + T 2 E g + T 2g 3 F A 2 + T 1 + T 2 A 2g + T 1g + T 2g 4 G A 1 + E + T 1 + T 2 A 1g + E g + T 1g + T 2g 5 H E + 2 T 1 + T 2 E g + 2 T 1g + T 2g 5 . TERM SPLITTING 6

7. TANABE –SUGUNO DIAGRAM FOR d 2 and d 8 IONS Fig T-S diagram for d 2 ions 7

8. Fig T-S diagram for d 8 ions 8

9. Some lines are curved this arises because whenever two states of the symmetry (same term symbol) are close in energy ,they can be combined to yield one sate of lower energy and another of higher energy . In a Tanabe- sugano diagram this makes it appear that some lines bend away from each other to avoid crossing. Transition involving these curved lines must be avoided when determining Δ o from Tanabe- sugano diagram 2. For some configuration there is abrupt change of slope and the ground state term also changes .this happen there is a transitions from a high spin to low spin state 9

10. CONCLUSION The Tanabe-Sugano diagram is a powerful tool for understanding the electronic transitions metal ions in different oxidation states. For d 2 and d 8 ions ,the diagram provide crucial insights into their spectroscopic properties ,such as ligand field splitting and the relative energies of different electronic states. By analyzing these diagram, researchers can predict and interpret the absorption spectra of transition metal complexes. 10

11. REFERENCE Coordination chemistry – AJAI KUMAR page number 49-51 Coordination chemistry-V Ramalingam page number 95-99 Inorganic chemistry(principle of structure and reactivity )- james E Huheey,Etion A.keiter Richard L.keiter,okhal k.medhl page number 746-748 11

12. THANK YOU 12