Trimethylborane

Trimethylborane is a chemical compound with the chemical formula B(CH3)3. This organoborane is a colorless, volatile liquid that is stable in the absence of air. It is a Lewis acid, and as such, it can react with Lewis bases to form adducts.

Structure and Bonding

Trimethylborane has a trigonal planar structure, similar to other organoboranes. The boron atom is located at the center of the molecule, with the three methyl groups surrounding it. The boron atom forms three covalent bonds with the carbon atoms of the methyl groups. The boron atom also has an empty p-orbital that can accept a pair of electrons from a Lewis base, forming a coordinate covalent bond.

Synthesis

Trimethylborane can be synthesized by the reaction of chloromethane with lithium borohydride in the presence of diethyl ether. The reaction proceeds via a nucleophilic substitution mechanism, with the borohydride ion acting as the nucleophile.

Reactions

Trimethylborane is a Lewis acid, and it can react with Lewis bases to form adducts. For example, it can react with ammonia to form the adduct (CH3)3B-NH3. It can also react with alkenes in the presence of a catalyst to form alkylboranes, which can be further converted into alcohols or amines via hydroboration-oxidation or hydroboration-amination reactions, respectively.

Safety

Trimethylborane is a highly flammable liquid. It can react with air to form explosive mixtures. It can also cause burns and eye damage. Therefore, it should be handled with care, using appropriate personal protective equipment.