Periodic Table
T-Shirts & more
from the
meta-synthesis


  See More  



Merch Store

Type 13 Lewis Acid/Base Complexation Chemistry

s-HOMO Lewis bases are reducing agents, so complexation with hydride or hydrogen is also classed as reduction.

However, with respect to carbenium ions and organic chemistry, as C-H bonds are polarised C^δ––H^δ+, ie as weak Brønsted acids, Type 13 complexes reverse their C-H bond polarisation:

C⁺ +   H^–    →   C–H    →   C^δ––H^δ+

and so become Type 3 complexes.

Carbenium ion (ie where the Lewis acid = R₃C⁺ + hydride ion) complexation reactions are rare as both species interact strongly with their counter ions.

• The true X + Y → X-Y complexation reaction would have to be performed under high vacuum vapor phase conditions with the reactive species generated by an experimentally exotic process such as laser induced dissociation.
• Alkyl halides, such as 3-bromohexane, are readily reduced by H₂ plus a catalyst, or by hydride ion donor reagents, as are carbonyl functions.
• Proton abstraction may occur if there is an acidic proton present and a strongly basic hydride donor reagent is used.
• A few C-H functions can act donors of hydride ion: aldehydes in the Cannizzaro reaction and isopropoxide ions during Meerwein-Ponndorf-Varley reduction.