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Lewis Acid/Base Interaction Matrix Database


Type 24 Lewis Acid/Base Complexation Chemistry

π-Organometallic Chemistry
Bonding:

The bonding in π-organometallics must be considered using LCAO MO theory because the normal rules of valency break down. For example, is the valency of the Fe(II) ion in the metallocene in ferrocene, Fe(C5H5)2? Is the iron 2 valent or 10 valent?

The hapto nomenclature, ηx, where the hapacity (Wikipedia) gives the number of conjugated p orbitals which ligate to a metal, rather than the number of electrons.

Charge: Complexes may be negatively charged, positively charged or they may be neutral.
Chemistry:

There is a very extensive π-heavy metal chemistry known: all heavy metals are known to form π-organometallic compounds.

Lewis Base
Number of
p–
Orbitals
Number of
π–Electrons
   Lobe-HOMO
η1
2
   Carbene
η1
2
   Alkene
η2
2
   Allyl cation
η3
2
   Allyl anion
η3
4
   1,3-Diene
η4
4
   Cyclopentadienyl anion
η5
6
   Benzene
η6
6
   Tropylium cation
η6
6

For example, chromium metallocenes:

Crabtree's catalyst:

Congeneric Series: Few of much interest.
Type 24 Lewis acid/base complex (generic)
Benzenechromium tricarbonyl

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(Bicyclo[2.2.1]hepta-2,5-diene)rhodium(I) chloride dimer

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Bis(butadiene)iron monocarbonyl

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Bis-allyl palladium(II) chloride

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Bis-propene palladium(II) chloride

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Butadiene iron tricarbonyl

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di-µ-Chlorobis(1,5-cyclooctadiene) -dirhodium(I)

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Chromium carbonyl

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Cycloheptatriene chromium tricarbonyl

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Dicobalt octacarbonyl

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Diiron nonacarbonyl

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Dimanganese decacarbonyl

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Ferrocene

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Iron pentacarbonyl

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Nickelocene

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pi-Organometallic (generic)

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Titanocene dichloride

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Tropylium chromium tricarbonyl cation

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Uranocene

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Vanadium carbonyl

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Zeise's salt

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Zirconocene chloride hydride

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