organo mercuary compounds

1. ORGANO MERCUARY
COMPOUNDS
PRESENTED TO DR SHAISTA GILLANI
PRESENTED BY RIMSHA BAKHTAWAR RASHEED
FA -19-MSC(CHEM)006
DATE – 18-1-2021
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rimsha b.r organomercury compounds

2. CONTENTS
 INTRODUCTION
 STRUCTURE
 PREPARATION
 REACTIONS
 EXAMPLES
 APPLICATION
 QUIZ
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rimsha b.r organomercury compounds

3. INTRODUCTION
 Organomercury refers to the group of organometallic compounds that
contain mercury. Typically the Hg–C bond is stable toward air and moisture
but sensitive to light.
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rimsha b.r organomercury compounds

4. What are the
Chemical
Properties of
Mercury?
 Chemical
Formula
Hg Greek name, hydrargyrum, which means “liquid silver”
 Toxicity Highly toxic
 Reactivity with
acids
Reacts with some acids when they are hot, but does not react with
most cold acids
 Oxidation Does not readily react with oxygen in the air
 Compounds
Many of mercury's compounds are in pigments, pesticides and
medicines.
Vermilion, a vivid red pigment is a chemical compound of mercury
and sulfur and is known as red sulfide of mercury
Mercuric chloride HgCl2, is used as an insecticide, in rat poison.
 Amalgam
Mercury forms a special type of alloy called an amalgam which is
an alloy containing mercury. An amalgam of mercury, silver and tin
is used in dentistry for filling teeth.
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rimsha b.r organomercury compounds

5. IMP COMPOUNDS
 Important organomercury compounds
 methylmercury(II) cation, CH3Hg+;
 Ethyl mercury (II) cation, C2H5Hg+
 dimethyl mercury, (CH3)2Hg
 diethyl mercury
 merbromin ("Mercurochrome").
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rimsha b.r organomercury compounds

6. SYNTHESIS
Organomercury compounds are prepared by many
methods, including the direct reaction of hydrocarbons and
mercury(II) salts. In this regard, organomercury chemistry
more closely resembles organopalladium chemistry and
contrasts with organocadmium compounds.
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rimsha b.r organomercury compounds

7. SYNTHESIS
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rimsha b.r organomercury compounds

8. SYNTHESIS
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rimsha b.r organomercury compounds

9. SYNTHESIS
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rimsha b.r organomercury compounds

10. SYNTHESIS
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rimsha b.r organomercury compounds

11. CONTINUE
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 Aryl iodide do not generally react with metallic mercury but perfluroaryliodide do
give rise to arylmercurials at elevated temperature.
rimsha b.r organomercury compounds

12. SYNTHESIS
 5) FROM SODIUM AMALGAM
useful for synthesis of organomercurates
I and Br react readily Cl give lower yield.
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rimsha b.r organomercury compounds

13. SYNTHESIS
 6) Electrochemical reduction of ketone provide alkyl mercurial but in lower yield.
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rimsha b.r organomercury compounds

14. REACTIONS
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Organomercury compounds are versatile synthetic intermediates due to the well
controlled conditions that they undergo cleavage of the Hg-C bonds.
Diphenyl mercury is a source of the phenyl radical in certain syntheses.
Treatment with aluminum gives triphenyl aluminium:
Ph2Hg + 2 Al → (AlPh3)2 + 3 Hg
rimsha b.r organomercury compounds

15. REACTIONS
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 HECK REACTION ( scientist reaction in 1968 )
 Prepare olefins
rimsha b.r organomercury compounds

16. REACTION
 OMDM ( OXYMERCURATION AND DEMERCURATION)
 IMPORTANT POINTS
 prepare alcohol by indirect addition of water.
 Mercuric acetate Hg( oAc )2 ,(CH3COO)Hg.
 NaBH4 ( reducing agent ).
 Follow markovnik rule.
 No rearrangement take place.
 TYPES
 1) FOR SYMMETRICAL ALKENE.
 2) FOR UNSYMMETRICAL ALKENE.
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rimsha b.r organomercury compounds

17.  FOR SYMMETRICAL ALKENE
 FOR UNSYMMETRICAL ALKENE
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rimsha b.r organomercury compounds

18. MECHANISM
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19. Reaction
 OXYMERCURATION OF AKENES
 When an alkene is treated with an alcohol in the presence of mercuric acetate
[Hg(OAc)2] it will add to the more substituted position of the alkene (Markovnikoff) to
give an ether. The mercury can then be removed using NaBH4.
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rimsha b.r organomercury compounds

20. Examples
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rimsha b.r organomercury compounds

21. Reaction
 REACTION BETWEEN ORGANOMERCURY AND NITROSYL COMPOUNDS
 The reaction between nitrosyl and organo mercury compounds were discovered by
action of nitrosyl bromide upon diphenyl mercury gives nitrosobenzene.
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rimsha b.r organomercury compounds

22. APPLICATIONS
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Compound Use
CH3HgX Agricultural seed dressing, fungicide
C2H5HgX Cereal seed treatment
RHgX Catalyst for urethane, vinyl acetate
production
C6H5HgX Seed dressing, fungicide, slimicide, general
bactericide. For pulp, paper, paints
ClCH2CH(OCH3)CH2HgX Fungicide, pesticide, preservative
Thimerosal Antiseptic, C2H5Hg derivative
Mercurochrome Antiseptic, organomercury fluorescein
derivative
rimsha b.r organomercury compounds

23. CONCLUSION
 The toxicity of organomercury compounds presents both dangers and
benefits. Dimethylmercury in particular, is notoriously toxic, but has found use
as an antifungal agent and insecticide. Merbromin is used as
a topical antiseptic.
 Due to its toxicity and low nucleophilicity, organomercury compounds find
limited use. The oxymercuration reaction of alkenes to alcohols using mercuric
acetate proceeds via organomercury intermediate
 Organomercury compounds such as aryl and alkoxy-aryl have been used in
medicine, agriculture, and laboratory research. Their use in fungicides has
been greatly reduced or eliminated.
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rimsha b.r organomercury compounds

24. Reference
 http://www.elementalmatter.info/mercury-properties.htm
 https://en.wikipedia.org/wiki/Organomercury
 https://youtu.be/inecTcspkbo
 https://youtu.be/D4V-C3avl6Y
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rimsha b.r organomercury compounds

25. QUIZ
 Why rearrangement not possible in organomercury reactions?
 Acrylate and RHgX gives --------------------?
 Organomercury + ---------------------- nitrsobenzene?
 Few application of orgnomercury compounds ?
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rimsha b.r organomercury compounds