Transmetalation From Boron to Beryllium in Phosphorus-Based Scorpionate Complexes

Area of Science:

• Organometallic Chemistry
• Boron Chemistry
• Beryllium Chemistry

Background:

• Tris(di-iso-propylphosphanylmethyl)phenylborate ([TP(iPr)]^-) is a versatile scorpionate ligand.
• Organoberyllium complexes are of interest due to beryllium's unique electronic properties.

Purpose of the Study:

• To investigate the reactivity of [TP(iPr)]^- with organoberyllium compounds.
• To understand the factors governing ligand transfer and complex stability.

Main Methods:

• Synthesis of organoberyllium complexes with varying R groups (Ph, nBu, Cp, Cp*).
• Investigation of transmetalation reactions.
• Ligand modification through oxidation with selenium, oxygen, and sulfur.

Main Results:

• Transmetalation of [CH₂P(iPr)₂]^- groups from boron to beryllium was observed.
• This process is facilitated by steric hindrance around beryllium or reduced B-L bond strength.
• Oxidation with selenium triggers transmetalation, while oxidation with oxygen or sulfur yields stable phosphine oxide/sulfide scorpionates.

Conclusions:

• The study reveals a new pathway for ligand exchange in organoberyllium chemistry.
• Steric and electronic properties of the ligand and metal center significantly influence reactivity.
• Selective oxidation provides a route to stable, modified scorpionate complexes.