Charge transfer- color of the complexes

Explanation for MLCT(Metal to Ligand Charge Transfer) and LMCT (Ligand to Metal Charge Transfer)

1. CHARGE TRANSFER COLOR OF COMPLEXES SHOBANA.N.S QUEEN MARY’S COLLEGE

2. INTRODUCTION Colour provides a vital enhancement to the world in which we live . Every day materials we use - textiles, paints, plastics, paper, and foodstuffs - are especially appealing if they are colourful.

3. ABSORPTION OF LIGHT

4. COLOR OF TRANSITION COMPLEXES DUE TO: 1. d-d transition 2. charge transfer 3. Spin allowed transition

5. CHARGE TRANSFER

6. WHAT DOES CHARGE -TRANSFER MEAN ?? Usually charge refers the charge of electron, which is being transferred within the molecular entity.

7. F our types of charge transfer complexes are known : LIGAND TO METAL CHARGE TRANSFER METAL TO LIGAND CHARGE TRANSFER METAL TO METAL CHARGE TRANSFER LIGAND TO LIGAND CHARGE TRANSFER

8. LIGAND TO METAL CHARGE TRANSFER COMPLEXES

9. Presence of pi donor ligands: F - , Cl, Br-, I - , H 2 O, OH - , RS - , S 2 - , NCS - , NCO. 2. Metal ions are devoid of d- electrons. CONDITION

10. METAL TO LIGAND CHARGE TRANSFER COMPLEXES

11. 1. Presence of pi accepting ligands CO, NO, CN - , N 2 , bipy , phen , RNC, C 5 H 5 - , C=C, C = C 2. Metal in 0,+1,+2 oxidation states ( low oxidation state). CONDITION

12. Tris ( bipyridine )ruthenium(II) dichloride [Ru( bpy ) 3 ]Cl 2 .

13. SPECTRA

14. KMnO4 Spectra LMCT

15. MLCT Tris ( bipyridine )ruthenium(II) dichloride

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