Charge transfer- color of the complexes

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

description

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

Transcript of Charge transfer- color of the complexes

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CHARGE TRANSFER

COLOR OF COMPLEXES

SHOBANA.N.S

QUEEN MARY’S COLLEGE

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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.

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ABSORPTION OF LIGHT

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COLOR OF TRANSITION COMPLEXES

• DUE TO:

1. d-d transition

2. charge transfer

3. Spin allowed transition

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CHARGE TRANSFER

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WHAT DOES CHARGE -TRANSFER MEAN ??

Usually charge refers the charge of electron, which is being transferred within the molecular entity.

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Four types of charge transfer complexes are known :

1. LIGAND TO METAL CHARGE TRANSFER

2. METAL TO LIGAND CHARGE TRANSFER

3. METAL TO METAL CHARGE TRANSFER

4. LIGAND TO LIGAND CHARGE TRANSFER

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LIGAND TO METAL CHARGE TRANSFER COMPLEXES

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1. Presence of pi donor ligands:

F-, Cl, Br-, I-, H2O, OH-, RS-, S2-, NCS-, NCO.

2. Metal ions are devoid of d- electrons.

CONDITION

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METAL TO LIGAND CHARGE TRANSFER COMPLEXES

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1. Presence of pi accepting ligands

CO, NO, CN-, N2, bipy, phen, RNC, C5H5-, C=C,

C=C

2. Metal in 0,+1,+2 oxidation states ( low oxidation

state).

CONDITION

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Tris(bipyridine)ruthenium(II)

dichloride

[Ru(bpy)3]Cl2.

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SPECTRA

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KMnO4 SpectraLMCT

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MLCTTris(bipyridine)ruthenium(II) dichloride

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THANK YOU !!!