Explain the Grignard reaction in detail.
(N/A) Organometallic compounds: Compounds in which a carbon atom is bonded to a metal atom are called 'organometallic' compounds. Most organic chlorides,bromides,and iodides react with certain active metals to form these compounds.
$(b)$ Grignard reagent: Organic halide compounds react with magnesium metal in dry ether to form alkyl magnesium halides $(RMgX)$,which are known as Grignard reagents.
$R - X + Mg \xrightarrow{\text{dry ether}} R^{-\delta} - Mg^{+\delta} - X^{-\delta}$
$CH_3CH_2Br + Mg \xrightarrow{\text{dry ether}} CH_3CH_2MgBr$
Victor Grignard discovered $RMgX$ in $1900$. It belongs to the class of organometallic compounds.
$(c)$ Reactivity and reactions: In Grignard reagents,the carbon-magnesium bond is not purely covalent but polar $(R^{-\delta} - Mg^{+\delta} - X^{-\delta})$ because magnesium is an electropositive metal. The carbon atom pulls electrons from magnesium,making the carbon partially negative. This makes the carbon highly reactive.
Grignard reagents react with any source of protons to form hydrocarbons:
$RMgX + H^+ \xrightarrow{OH^-} RH + Mg(OH)X$
They react with water,alcohols $(R'OH)$,and amines $(R'NH_2, R'_2NH)$,which act as proton donors.
$RMgX + H_2O \rightarrow RH + Mg(OH)X$
Example: $CH_3Br + Mg$ $\rightarrow CH_3MgBr$ $\xrightarrow{H_2O} CH_4 + Mg(OH)Br$
$(b)$ Grignard reagent: Organic halide compounds react with magnesium metal in dry ether to form alkyl magnesium halides $(RMgX)$,which are known as Grignard reagents.
$R - X + Mg \xrightarrow{\text{dry ether}} R^{-\delta} - Mg^{+\delta} - X^{-\delta}$
$CH_3CH_2Br + Mg \xrightarrow{\text{dry ether}} CH_3CH_2MgBr$
Victor Grignard discovered $RMgX$ in $1900$. It belongs to the class of organometallic compounds.
$(c)$ Reactivity and reactions: In Grignard reagents,the carbon-magnesium bond is not purely covalent but polar $(R^{-\delta} - Mg^{+\delta} - X^{-\delta})$ because magnesium is an electropositive metal. The carbon atom pulls electrons from magnesium,making the carbon partially negative. This makes the carbon highly reactive.
Grignard reagents react with any source of protons to form hydrocarbons:
$RMgX + H^+ \xrightarrow{OH^-} RH + Mg(OH)X$
They react with water,alcohols $(R'OH)$,and amines $(R'NH_2, R'_2NH)$,which act as proton donors.
$RMgX + H_2O \rightarrow RH + Mg(OH)X$
Example: $CH_3Br + Mg$ $\rightarrow CH_3MgBr$ $\xrightarrow{H_2O} CH_4 + Mg(OH)Br$
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Similar Questions
The correct statements about metal carbonyls are:
$A$. The metal-carbon bonds in metal carbonyls possess both $\sigma$ and $\pi$-character.
$B$. Due to synergic bonding interactions between metal and $CO$ ligand, the metal-carbon bond becomes weak.
$C$. The metal-carbon $\sigma$ bond is formed by the donation of a lone pair of electrons on the carbonyl carbon into a vacant orbital of metal.
$D$. The metal-carbon $\pi$ bond is formed by the donation of electrons from a filled $d$-orbital of metal into a vacant $\pi^*$ orbital of $CO$.
Choose the correct answer from the options given below:
$A$. The metal-carbon bonds in metal carbonyls possess both $\sigma$ and $\pi$-character.
$B$. Due to synergic bonding interactions between metal and $CO$ ligand, the metal-carbon bond becomes weak.
$C$. The metal-carbon $\sigma$ bond is formed by the donation of a lone pair of electrons on the carbonyl carbon into a vacant orbital of metal.
$D$. The metal-carbon $\pi$ bond is formed by the donation of electrons from a filled $d$-orbital of metal into a vacant $\pi^*$ orbital of $CO$.
Choose the correct answer from the options given below:
The number of bridging $CO$ ligand$(s)$ and $Co-Co$ bond$(s)$ in $Co_2(CO)_8$ respectively are
Which of the following organometallic compounds is both $\sigma$ and $\pi$ bonded?
Difficult
View SolutionThe $C-O$ bond length in carbon monoxide is $1.128 \ \mathring{A}$. The $C-O$ bond length in $Fe(CO)_5$ is equal to .......... $\mathring{A}$.
Medium
View SolutionAn example of a $\sigma$-bonded organometallic compound is:
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