Questions and Answers
What type of bond does a metal-ligand bond represent?
Which term describes a ligand that forms only one bond to a metal ion?
How many bonds can a bidentate ligand form with a metal ion?
What are coordination compounds containing polydentate ligands called?
Signup and view all the answers
According to Werner's theory, what are the two types of valencies that metals possess?
Signup and view all the answers
What do ligands that satisfy the secondary valencies in coordination compounds do?
Signup and view all the answers
Which of the following is an example of a polydentate ligand?
Signup and view all the answers
What role do phosphates play in hard water treatment?
Signup and view all the answers
What does the η value of a ligand indicate about its bonding mode with a metal center?
Signup and view all the answers
In the context of hapticity, what is true for odd η values of carbon ligands?
Signup and view all the answers
Which of the following statements correctly describes σ-bonded organometallic compounds?
Signup and view all the answers
What is the typical electron donation by a neutral ligand with an even η value?
Signup and view all the answers
Which class of organometallic compounds possesses both σ and π bonding?
Signup and view all the answers
How are the stability and reactivity of organometallic compounds influenced?
Signup and view all the answers
What characterizes pi (π) bonded organometallic compounds?
Signup and view all the answers
Which ligands typically utilize the ionic method of electron counting?
Signup and view all the answers
What does crystal field theory primarily suggest about bonding in metal-ligand complexes?
Signup and view all the answers
Which factor primarily determines the splitting of d-orbitals in crystal field theory?
Signup and view all the answers
In which scenario would you expect to see a smaller degree of crystal field splitting in d-orbitals?
Signup and view all the answers
What does the term 'crystal field splitting energy' refer to?
Signup and view all the answers
Which type of ligand typically causes a larger splitting of the d-orbitals in complexes?
Signup and view all the answers
What is the primary type of interaction between the ligands and the metal ion in crystal field theory?
Signup and view all the answers
Which of the following best describes a high-spin configuration in d4 to d7 metal ions?
Signup and view all the answers
What can be inferred about the stability of organometallic compounds in relation to ligands?
Signup and view all the answers
Study Notes
Hapticity and Ligand Bonding
- Hapticity refers to the mode of bonding between a ligand and a metal center.
- For η5-cyclopentadienyl (Cp) ligand, all five carbons engage in bonding with the transition metal.
- Odd ηx values for carbon ligands generally indicate anionic forms (e.g., η5-Cp, η1-CH3, η1-allyl).
- Electron donation from ligands is often calculated as x + 1 for odd ηx values.
- Even ηx values characterize neutral carbon π-system ligands (e.g., η6-C6H6, η2-CH2=CH2).
- In neutral cases, electron donation equals x for even ηx values.
Classification of Organometallic Compounds
- Sigma (σ) bonded compounds involve a direct sigma bond between metal and carbon (e.g., Grignard reagents, zinc compounds).
- Dimeric compound Al2(CH3)6 resembles diborane (B2H6) and is electron deficient.
- Pi (π) bonded compounds involve bonding with π-electrons from alkenes, alkynes, and aromatic compounds (e.g., Zeise’s salt, ferrocene, dibenzene chromium).
- Sigma and π-bonded organometallic compounds, such as metal carbonyls, involve both types of bonding.
Chelating Agents
- Chelates are coordination compounds with polydentate ligands form multiple bonds to a metal without excessive strain.
- Ethylenediamine is an example of a polydentate ligand forming chelates.
- Biomolecules like heme and chlorophyll are porphyrins, showcasing important chelating functions.
- Phosphates complex with Ca²⁺ and Mg²⁺ in hard water to enhance detergent effectiveness.
Werner Coordination Theory
- Proposed by Alfred Werner in 1892 to explain formation of complex compounds.
- Metals have primary (ionizable) and secondary (non-ionizable) valencies.
- Coordination involves satisfying both valencies; secondary valencies bond directionally, imparting specific geometry.
Crystal Field Theory (CFT)
- CFT describes the electronic structure through an ionic model, treating ligands as point charges.
- Bonding occurs purely through electrostatic interactions without orbital hybridization.
- Ligand attachment causes splitting of d-orbitals; different energies arise, grouping into sets (e.g., e_g and t_2g).
- In octahedral complexes, two key electrostatic interactions exist: attraction between the positive metal ion and negative ligands, and repulsion between lone pairs in ligands and d-orbital electrons.
High- and Low-Spin Complexes
- High-spin complexes often result from weak-field ligands leading to lesser splitting of d-orbitals.
- Low-spin complexes arise from strong-field ligands which cause significant d-orbital energy splitting.
- The energy difference due to crystal field splitting can be quantified through UV-Vis spectroscopy.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Explore the fascinating world of hapticity and ligand bonding modes in transition metal complexes. This quiz delves into the electron donation characteristics of various carbon ligands like η5-cyclopentadienyl and their implications in coordination chemistry. Test your understanding of how different hapticity values affect metal-ligand interactions.
