Hey, guys! It’s been forever, hasn’t it? [laughs sadly] I’m back to studying, and this time, I’m putting together a ligand sheet.
I apologize in advanced, because this might not be the most fascinating thing, but I’ll be referencing these a lot in my next posts, and I need to know them anyway, sooo…
(I’m still watching the cat video. ^^)
Ligand Toolkit
Hydrogen Ligands:
Hydrido: H–
- Two-electron donor
- No pi accepting ability
- Bonds to soft metals
- Negatively charged
Carbon Ligands:
Carbonyl: CO
- Two-electron sigma donor through carbon
- Pi-accepting into pi antibonding orbitals
- Bonds to soft metals
- Neutral charge
Cyanido: CN–
- Two-electron sigma donor through carbon
- Pi-accepting into pi antibonding orbitals
- Bonds to hard and soft metals
- Negatively charged
Alkenes
- Two-electron sigma donor through pi orbitals
- Pi-accepting into pi antibonding orbitals
- Bond to soft and hard metals
- Neutral charge
Alkynes
- Two-electron (monodentate) or four-electron (bidentate bridging) sigma donors through pi orbitals
- Pi-accepting into pi antibonding orbitals
- Bond to soft and hard metals
- Neutral charge
Cyclic Aromatic
Benzene: η6-C6H6
- Six-electron sigma donor through pi orbitals
- Pi-accepting into pi antibonding orbitals
- Bonds to soft metals
- Neutral charge
Cyclopentadienyl: η5-C5H5–
- Six-electron sigma donor through pi orbitals
- Pi-accepting into pi antibonding orbitals
- Bonds to soft and hard metals
- Negatively charged
Carbene
Carbenes: CRR’
- Two-electron sigma donor through sp2 on carbon
- Pi-accepting into 2p orbital on carbon
- Bond to soft metals
- Neutral charge
Carbanion
Alkyl and Aryl Carbanions
- Two-electron sigma donor through sp3 on carbon
- Possible pi-accepting on aryl carbanions through pi antibonding orbitals
- Bond to soft and hard metals
- Negatively charged
Acyl
Acyl: C(O)R–
- Two-electron sigma donor through sp2 on carbon
- Possible pi-accepting through pi antibonding orbitals
- Bond to soft metals
- Negatively charged
Allyl
Allyl: η3-C3H5–
- Four-electron sigma donor through pi orbitals
- Pi-accepting through pi antibonding orbitals
- Bonds to soft metals
- Negatively charged
Nitrogen Ligands:
Aliphatic Amines
- Two-electron sigma donor through sp3 on nitrogen
- No pi accepting
- Bond to hard metals
- Neutral charge
Heterocyclic Nitrogen Bases (Pyridine, Imidazole, etc.)
- Two-electron sigma donor through sp2 on nitrogen
- Possible pi-accepting into pi antibonding orbitals
- Bonds to soft and hard metals
- Neutral charge
Imines: C=N
- Two-electron sigma donor through sp2 on nitrogen
- Pi-accepting into pi antibonding orbitals
- Bonds to soft and hard metals
- Neural charge
Nitrile: R-CN
- Two-electron sigma donor through sp on nitrogen
- Possible pi-accepting into pi antibonding orbitals
- Bonds to soft and hard metals
- Neural charge
Dinitrogen: N2
- Two-electron sigma donor through sp on nitrogen
- Pi-accepting into pi antibonding orbitals
- Bonds to soft metals
- Neural charge
Nitrosyl: NO
- Has two forms: linear (triple bonded) and bent (double bonded)
Linear Nitrosyl:
- Two-electron sigma donor through sp on nitrogen
- Pi-accepting into pi antibonding orbitals
- Bonds to soft metals
- Positive charge
Bent Nitrosyl:
- Two-electron sigma donor through sp2 on nitrogen
- Pi-accepting into pi antibonding orbitals
- Bonds to soft metals
- Negative charge
Phosphorus Ligands:
Phosphine, Phosphite
- Two-electron sigma donor per phosphorus
- Pi-accepting into d orbitals (in phosphite)
- Bonds to soft metals
- Neutral charge
Oxygen Ligands:
Ether, Alcohol, Aqua
- Two-electron sigma donors
- No pi backbonding
- Weaky bond to hard metals
- Neutral charge
Alkoxo an Aryloxo: RO–
- Two-electron donors
- No pi backbonding
- Strongly bond to hard metals
- Negatively charged
Beta-Diketonato
- Four-electron donors (chelating)
- Pi-accepting through pi antibonding orbitals
- Bond to soft and hard metals
- Negatively charged
Carboxylato
- Two-electron donors per carboxylato group
- No pi-backbonding
- Bond to hard metals
- Negatively charged
Sulfur Ligands:
Thiolato
- Two-electron donors
- No pi-backbonding
- Bond to soft metals
- Negatively charged
Dithiocarbamato
- Four-electron donor (chelating)
- No pi-backbonding
- Negatively charged
Halide Ligands:
Halido
- Either two-electron donor or four-electron bridging
Macrocyclic Ligands:
Porphyrinato, Crown Ethers, Cryptands
- Form more stable complexes than equivalent numbers of nonchelating ligands
All right! That’s it! I’m done! Now I’m going to watch the Iron Bowl! (Not that I have a choice… I’m basically watching it right now, so…)