Slide 2 - Types of Ligands

• Mono dentate ligand: Ligands that form only one bond with the metal atom or ion. Example: NH3, H2O
• Bidentate ligand: Ligands that can form two bonds with the metal atom or ion. Example: ethylenediamine (en), oxalate ion (C2O4^2-)
• Polydentate ligand: Ligands that can form multiple bonds with the metal atom or ion. Example: ethylenediaminetetraacetate (EDTA)

Slide 3 - Isomerism in Coordination Compounds

• Stereoisomerism:
  • Geometric isomerism: Same chemical formula, but differ in spatial arrangement.
  • Optical isomerism: Non-superimposable mirror images of each other.
• Coordination isomerism:
  • Exchange of ligands between the metal atom or ion and the counter ions.
• Linkage isomerism:
  • Existence of different isomeric compounds due to a ligand which can bind through different atoms or through different bonds.

Slide 4 - Werner’s Theory of Coordination Compounds

• Propounded by Alfred Werner in 1893.
• Central atom or ion is linked to ligands by primary or secondary valencies.
• Coordination number: Number of ligands coordinated to the central metal ion.
• Primary valency: Indicates the oxidation state of the central atom or ion.
• Secondary valency: Indicates the coordination number of the central atom or ion.

Slide 5 - Hybridization of Central Metal Atom with Ligands

• Hybridization refers to the mixing of atomic orbitals to form new hybrid orbitals.
• Hybrid orbitals determine the geometry around the central metal atom. Examples of hybridization:
• [Fe(CN)6]4-: Fe(III) has d^2sp^3 hybridization.
• [Co(NH3)6]3+: Co(III) has d^2sp^3 hybridization.
• [CuCl2(H2O)4]: Cu(II) has d^2sp^3 hybridization.

Slide 6 - Shapes and Structures of Coordination Compounds

• Square planar: Coordination number 4, d^2sp^3 hybridization.
• Tetrahedral: Coordination number 4, sp^3 hybridization.
• Octahedral: Coordination number 6, d^2sp^3 hybridization.
• Linear: Coordination number 2, sp hybridization.

Slide 7 - Crystal Field Theory (CFT)

• CFT explains the stability and color observed in coordination compounds.
• It is based on the interaction between the d-orbitals of the central metal atom and the ligands.
• Splitting of d-orbitals into two energy levels: eg and t2g.
• The energy difference between eg and t2g levels corresponds to the absorbed or emitted light, giving the compound its color.

Slide 8 - Colors of Transition Metal Complexes

• Color arises due to d-d transitions.
• Different ligands can cause different energy levels of d-orbitals.
• Greater energy difference between eg and t2g levels results in higher energy light absorbed, and vice versa.
• Examples:
  • Cu(II) with Cl ligands appears blue due to high energy absorption.
  • Cu(II) with NH3 ligands appears green due to lower energy absorption.

Slide 9 - Nomenclature of Coordination Compounds

• Cationic part is written first, followed by the anionic part.
• Nomenclature of cationic part:
  • The name of the metal is written first, followed by the oxidation state in Roman numerals in parentheses.
  • Example: Iron(III)
• Nomenclature of anionic part:
  • The name of the ligand is written, followed by the metal name ending in -ate.
  • Example: Chlorido, Nitrito, Aquo

Slide 10 - Isomerism in Coordination Compounds

• Structural isomerism:
  • Linkage isomerism: Different bond formation between the central atom and ligands.
  • Ionization isomerism: Exchange of ligand with the same molecular formula but different connectivity.
  • Coordination isomerism: Exchange of ligand between the cationic and anionic parts.
• Coordination compounds exhibit a variety of isomerism due to the different arrangements of ligands around the central metal atom or ion.

Slide 11 - Coordination Compounds: Hybridization of Central Metal Atom with Ligands

• Hybridization refers to the mixing of atomic orbitals to form new hybrid orbitals.
• The type of hybridization determines the geometry and shape around the central metal atom.
• Different types of hybridization can occur depending on the coordination number and ligands involved.
• Examples of hybridization in coordination compounds include sp, sp^2, sp^3, dsp^2, and d^2sp^3.
• The type of hybridization influences the magnetic properties, reactivity, and bonding in coordination compounds.

Slide 12 - sp Hybridization in Coordination Compounds

• Occurs when the central metal atom or ion has a coordination number of 2.
• The s orbital and one p orbital from the metal atom combine to form two sp hybrid orbitals.
• The sp hybrid orbitals are linearly oriented at an angle of 180 degrees.
• Examples: [Ni(CO)4], [PtCl2(NH3)2]

Slide 13 - sp^2 Hybridization in Coordination Compounds

• Occurs when the central metal atom or ion has a coordination number of 3.
• The s orbital and two p orbitals from the metal atom combine to form three sp^2 hybrid orbitals.
• The sp^2 hybrid orbitals are trigonally planarly oriented at an angle of 120 degrees.
• Examples: [Cu(CN)3]2-, [Co(NH3)3]+

Slide 14 - sp^3 Hybridization in Coordination Compounds

• Occurs when the central metal atom or ion has a coordination number of 4.
• The s orbital and three p orbitals from the metal atom combine to form four sp^3 hybrid orbitals.
• The sp^3 hybrid orbitals are tetrahedrally oriented at an angle of 109.5 degrees.
• Examples: [Ni(CO)4], [Zn(NH3)4]2+

Slide 15 - dsp^2 Hybridization in Coordination Compounds

• Occurs when the central metal atom or ion has a coordination number of 4 and there are two lone pairs of electrons.
• The dxy, dxz, dyz, and dz^2 orbitals from the metal atom combine with one s and two p orbitals to form five dsp^2 hybrid orbitals.
• The dsp^2 hybrid orbitals are trigonal bipyramidal in shape.
• Examples: [Fe(CO)5], [Cu(NH3)4]2+

Slide 16 - d^2sp^3 Hybridization in Coordination Compounds

• Occurs when the central metal atom or ion has a coordination number of 6.
• The dxy, dxz, dyz, dz^2, and dx^2-y^2 orbitals from the metal atom combine with one s and three p orbitals to form six d^2sp^3 hybrid orbitals.
• The d^2sp^3 hybrid orbitals are octahedrally oriented at an angle of 90 degrees.
• Examples: [Cr(H2O)6]3+, [Co(NH3)6]3+

Slide 21 - Coordination Compounds: Hybridization of Central Metal Atom with Ligands

• Hybridization determines the shape and geometry of coordination compounds.
• Hybridization involves the mixing of atomic orbitals to form new hybrid orbitals.
• Different types of hybridization can occur depending on the coordination number and ligands.
• sp hybridization:
  • Occurs when the central metal atom or ion has a coordination number of 2.
  • One s orbital and one p orbital from the metal atom combine to form two sp hybrid orbitals.
  • Examples: [PtCl2(NH3)2], [Ag(CN)2]-
• sp^2 hybridization:
  • Occurs when the central metal atom or ion has a coordination number of 3.
  • One s orbital and two p orbitals from the metal atom combine to form three sp^2 hybrid orbitals.
  • Examples: [Co(NH3)3]+, [Cu(CN)3]2-
• sp^3 hybridization:
  • Occurs when the central metal atom or ion has a coordination number of 4.
  • One s orbital and three p orbitals from the metal atom combine to form four sp^3 hybrid orbitals.
  • Examples: [NiCl4]2-, [Zn(NH3)4]2+
• dsp^2 hybridization:
  • Occurs when the central metal atom or ion has a coordination number of 4 with two lone pairs of electrons.
  • One d orbital and two p orbitals from the metal atom combine with one s orbital to form five dsp^2 hybrid orbitals.
  • Examples: [Fe(CO)5], [Cu(NH3)4]2+
• d^2sp^3 hybridization:
  • Occurs when the central metal atom or ion has a coordination number of 6.
  • Two d orbitals and three p orbitals from the metal atom combine with one s orbital to form six d^2sp^3 hybrid orbitals.
  • Examples: [Cr(H2O)6]3+, [Co(NH3)6]3+

Slide 22 - Hybridization Examples

• Example 1: sp hybridization in [Ag(CN)2]-
  • Coordination number = 2
  • 1s orbital and 1p orbital from Ag atom combine to form two sp hybrid orbitals.
  • Linear arrangement, bond angle = 180 degrees.
• Example 2: sp^2 hybridization in [Cu(CN)3]2-
  • Coordination number = 3
  • 1s orbital and 2p orbitals from Cu atom combine to form three sp^2 hybrid orbitals.
  • Trigonal planar arrangement, bond angle = 120 degrees.
• Example 3: sp^3 hybridization in [Zn(NH3)4]2+
  • Coordination number = 4
  • 1s orbital and 3p orbitals from Zn atom combine to form four sp^3 hybrid orbitals.
  • Tetrahedral arrangement, bond angle = 109.5 degrees.

Slide 23 - Hybridization Examples (Contd.)

• Example 4: dsp^2 hybridization in [Fe(CO)5]
  • Coordination number = 5
  • 1d orbital, 2p orbitals, and 1s orbital from Fe atom combine to form five dsp^2 hybrid orbitals.
  • Trigonal bipyramidal arrangement.
• Example 5: d^2sp^3 hybridization in [Cr(H2O)6]3+
  • Coordination number = 6
  • 2d orbitals, 3p orbitals, and 1s orbital from Cr atom combine to form six d^2sp^3 hybrid orbitals.
  • Octahedral arrangement.
• Hybridization plays a crucial role in determining the shape, geometry, and properties of coordination compounds.

Slide 24 - Importance of Hybridization in Coordination Chemistry

Hybridization is significant in coordination chemistry for various reasons:

• Predicting the geometry and shape of coordination compounds.
• Understanding the reactivity and bonding in coordination compounds.
• Explaining the magnetic properties and spectroscopic behavior of coordination compounds.
• Determining the stability and color observed in coordination compounds.
• Providing a basis for the naming and characterization of coordination compounds. The knowledge of hybridization helps in analyzing and explaining various properties and behaviors of coordination compounds.

Slide 25 - Summary

In summary:

• Hybridization is based on the mixing of atomic orbitals to form new hybrid orbitals.
• Different types of hybridization occur depending on the coordination number and ligands present.
• Examples include sp, sp^2, sp^3, dsp^2, and d^2sp^3 hybridizations.
• Hybridization determines the geometry, shape, and properties of coordination compounds.
• Understanding hybridization is crucial for studying coordination chemistry and analyzing its various aspects.

Slide 26 - References

• Textbook: Organic Chemistry by Morrison & Boyd (2011)
• Textbook: Inorganic Chemistry by Housecroft & Sharpe (2012)
• Journal Article: “Coordination Chemistry and Bonding in Transition Metal Complexes” by Jens Muller (Chemical Reviews, 2008)
• Lecture Notes: Coordination Chemistry lecture series by Prof. John Smith (University of XYZ) Note: The references provided are for further reading and exploration on the topic.