Flashcards on Inorganic Chemistry: Spectra and Complexes
Inorganic Chemistry: Spectra & Complexes - Student Guide
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Organometallic Chemistry
41 cards
Card 1
Question: How does a positive charge on a metal center affect metal orbitals and M–C/C–O bond strengths?
Answer: Positive charge: metal orbitals are contracted, overlap with ligand orbitals is poorer, M–C bond is weaker, and C–O bond is stronger.
Card 2
Question: How does a negative charge on a metal center affect metal orbitals and M–C/C–O bond strengths?
Answer: Negative charge: metal orbitals expand, overlap with ligand orbitals improves, M–C bond is stronger, and C–O bond is weaker.
Card 3
Question: State the 18-electron rule in organometallic chemistry.
Answer: A stable configuration has ns2 (n‑1)d10 np6 = 18 electrons; most stable complexes have bonding orbitals filled and antibonding orbitals empty.
Card 4
Question: When counting electrons for the 18‑electron rule, how is the metal treated and how are ligand types counted?
Answer: Treat the metal as M(0) and use its group valence electrons; ligand contributions: X-type ligands = 1 e- each, L-type ligands = 2 e- each. Adjust for
Card 5
Question: How is an M–M bond counted in electron counting for each metal?
Answer: Each M–M bond contributes 1 electron to each metal.
Card 6
Question: What is the hapto (η) notation and what does it indicate?
Answer: The hapto symbol η with a superscript indicates the number of contiguous atoms of a ligand bonded to the metal (connectivity). Example: η5‑cyclopentad
Card 7
Question: What does the mu (μ) symbol indicate in ligand notation?
Answer: The mu symbol indicates a bridging ligand between metal centers, commonly μ2 and sometimes μ3.
Card 8
Question: Give examples of common η (hapticity) notations for hydrocarbon ligands.
Answer: Examples: η1‑R, η1‑Ar, η2‑C2R4, η1‑allyl, η3‑allyl, η4‑C4H6, η5‑C5H5, η6‑C6R6.
Card 9
Question: What are typical electron counts for CO, phosphine (PR3), and η5‑cyclopentadienyl ligands?
Answer: CO = 2 e‑, PR3 = 2 e‑, η5‑cyclopentadienyl = 5 e‑.
Card 10
Question: How many electrons does a hydride (H−) ligand contribute?
Answer: Hydride (M–H) contributes 1 electron.