Double silyl migration converting ORe[N(SiMe(2)CH(2)PCy(2))(2)] to NRe[O(SiMe(2)CH(2)PCy(2))(2)] substructures

Area of Science:

• Organometallic Chemistry
• Inorganic Chemistry
• Computational Chemistry

Background:

• The synthesis of transition metal complexes with unique ligand environments is crucial for catalysis and materials science.
• Phosphorus-nitrogen-phosphorus (PNP) ligands offer versatile coordination modes for stabilizing reactive metal centers.

Purpose of the Study:

• To synthesize and characterize novel rhenium complexes featuring PNP ligands.
• To investigate the reactivity of these complexes, particularly silicon migration reactions.
• To elucidate the thermodynamic stability of different isomeric forms using computational methods.

Main Methods:

• Reaction of PNP ligands with rhenium precursors (L(2)ReOX(3)).
• Isolation and characterization of isomeric products ((PNP(Cy))ReOX(2)).
• Thermal rearrangement studies leading to new isomers ((POP(Cy))ReNX(2)).
• Density Functional Theory (DFT) calculations for structural and stability analysis.

Main Results:

• Two isomers, mer,trans and mer,cis, of (PNP(Cy))ReOX(2) were obtained.
• A double silicon migration from nitrogen to oxygen occurred at 90°C, forming (POP(Cy))ReNX(2) isomers.
• Further thermolysis induced methyl and halide migration between silicon and rhenium.
• DFT calculations confirmed the higher thermodynamic stability of the POP/ReN isomer over the PNP/ReO isomer.

Conclusions:

• The study successfully synthesized and characterized novel rhenium-PNP complexes.
• Silicon migration reactions demonstrate a pathway for ligand rearrangement and formation of new coordination environments.
• DFT calculations provide valuable insights into the energetic preferences of different isomers and reaction pathways.
• The findings highlight the influence of the template effect on the reactivity and stability of these organometallic species.