The document discusses migratory insertion reactions involving organometallic complexes, detailing 1,1 and 1,2 insertion mechanisms. It highlights the requirements for these reactions, such as the necessity of cisoidal ligands and the unaltered oxidation states of metal centers. The text also outlines general features, types, and mechanisms associated with these reactions, supported by references for further study.

1. Department of Chemical Sciences, UENR , Sunyani, Ghana
KNOWLEDGE INTEGRITY IMPACT
ORGANOMETTALLIC REACTIONS
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1,1 AND 1,2 MIGRATORY REACTIONS
BOAKYE EMMANUEL GYAU

2. Department of Chemical Sciences, UENR , Sunyani, Ghana
KNOWLEDGE INTEGRITY IMPACT
TABLE OF CONTENT
 Introduction
 General fearures
 Types of Migratory Insertions
 Migration vs. Insertion
 Mechanism of 1,1 Migratory Insertion
 Mechanism of 1,2 Migratory Insertion
 Conclusion
 References

3.  A migratory insertion reaction is when a cisoidal anionic and
neutral ligand on a metal complex couple together to generate
a new coordinated anionic ligand.
 This new anionic ligand is composed of the original neutral and
anionic ligands now bonded to one another.
 There is NO change in the oxidation state or d electron- count
of the metal center
Migratory Insertion
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4.  Ligand Insertions is reversible
 No change in formal oxidation state of the metal
 The two groups that react must be cisoidal to one another
 A vacant coordination site is generated by the migratory insertion.
Therefore, a vacant site is required for the back elimination reaction. A
trapping ligand is often needed to coordinate to the empty site formed
from a migratory insertion in order to stop the back elimination
reaction.
General Featuresof Migratory Insertion
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5.  Migratory insertions are usually favored on more electron-deficient
metal centers.
 Ligands that undergo must have pi bonds present (eg- CO)
 Common anionic and neutral ligands that can do migratory insertion
reactions with one another:
 Anionic: H-, R- (alkyl), Ar- (aryl), acyl-, O2- (oxo)
 Neutral: CO, alkenes, alkynes, carbenes
 No change in overall charge of the complex
 If 2 akyle groups are attached to the metal, the electron rich group is
migrated.
General Features of Migratory Insertion
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6.  The type of insertion observed in any given case depends on the nature of the 2e
inserting ligand.
 Type 1: 1,1 insertion in which the metal and the X ligand end up bound to the same
(1,1) atom. CO gives only 1,1 insertion
 Type 2: 1,2 insertion in which the metal and the X ligand end up bound
to adjacent (1,2) atoms of an L-type ligand. Ethylene gives only 1,2
insertion, in which the M and the X end up on adjacent atoms of what
was the 2e X-type ligand.
Types of Migratory Insertion
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7.  There are two different “directions” that a migratory insertion
can occur.
 A migration is when the anionic ligand moves and performs a
nucleophillic-like intramolecular attack on the electrophillic
neutral ligand.
 An insertion is when the neutral ligand moves and “inserts” into
the bond between the metal and anionic ligand. Both of these
pathways are illustrated below
Migration vs. Insertion
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8. KNOWLEDGE INTEGRITY IMPACT
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9. Department of Chemical Sciences, UENR , Sunyani, Ghana
KNOWLEDGE INTEGRITY IMPACT
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Department of Chemical Sciences, UENR 9

10.  Principle- the migrating group will migrate to the cis ligand attached to it
 Steps
 The reaction starts with a metal complex where the metal (M) is bonded to an alkyl or
aryl group (R) and an unsaturated ligand (L), such as an alkene, alkyne, or CO
 The alkyl or aryl group (R) migrates to the same ligand site of the unsaturated ligand
(L) leading to the formation of a new bond between R and L at the same metal center.
Reaction Mechanism of 1,1 Migratory Insertion
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11. Reaction Mechanisms of 1,1 Migratory Insertion
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12.  1,2 insertion in which the metal and the X ligand end up bound to
adjacent (1,2) atoms of an L-type ligand
 It involves 2 principle; the formation of alkenes in between the M-H bond
and the M-R bond and the migration of the H and alkyl group
 It tends to elongate the carbon chain of the alkene ligand
Reaction Mechanism of 1,2 Migratory Insertion

13. Reaction Mechanism of 1,2 Migratory Insertion

14.  Fristrup, Peter; Kreis, Michael; Palmelund, Anders; Norrby, Per-Ola; Madsen, Robert (2008). "The
Mechanism for the Rhodium-Catalyzed Decarbonylation of Aldehydes: A Combined Experimental and
Theoretical Study". J. Am. Chem. Soc. 130 (15): 5206–5215. doi:10.1021/ja710270
 Hartwig, J. F. (2010). Organotransition Metal Chemistry, from Bonding to Catalysis. New York, NY:
University Science Books. ISBN 978-1-891389-53-5.
 Burger, B. J.; Thompson, M. E.; Cotter, W. D.; Bercaw, J. E. (1990). "Ethylene Insertion and β-
hydrogen Elimination for Permethylscandocene Alkyl Complexes. A Study of the Chain Propagation
and Termination Steps in Ziegler-Natta Polymerization of Ethylene". J. Am. Chem. Soc. 112 (4): 1566–
1577.
REFERENCES

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