Phosphoramidate-Supported Cp*Ir(III) Aminoborane H2 B=NR2 Complexes: Synthesis, Structure, and Solution Dynamics

Area of Science:

• Organometallic Chemistry
• Inorganic Chemistry
• Computational Chemistry

Background:

• Aminoboranes (H2B=NR2) are versatile inorganic compounds.
• Cationic iridium(III) complexes offer unique reactivity.
• Phosphoramidate ligands can coordinate to metal centers.

Purpose of the Study:

• To synthesize and characterize novel aminoborane complexes of iridium(III).
• To investigate the effect of phosphoramidate coordination on the B=N bond.
• To study the dynamic behavior of coordinated aminoboranes.

Main Methods:

• Synthesis of iridium(III) phosphoramidate complexes.
• Reaction with aminoboranes (R=iPr or Cy).
• Solution- and solid-state characterization.
• Density Functional Theory (DFT) calculations.

Main Results:

• Formation of novel aminoborane complexes: [IrCp*(H){κ(1) -N-η(2) -HB-Xyl(N)P(OBHNR2 )(OEt)2 }][BAr(F) 4 ].
• Coordination of the phosphoramidate P=O to boron weakens the B=N multiple bond.
• Evidence for B-N bond rotation in the coordinated aminoborane.

Conclusions:

• The electronic effects of the phosphoramidate ligand facilitate B-N bond weakening.
• The synthesized complexes exhibit dynamic B-N bond rotation.
• This study provides insights into the reactivity and bonding of aminoboranes in organometallic complexes.