A "Push-Pull" Stabilized Phosphinidene Supported by a Phosphine-Functionalized β-Diketiminato Ligand

Area of Science:

• Organometallic Chemistry
• Main Group Chemistry
• Ligand Design

Background:

• Diketiminate ligands offer tunable coordination environments.
• Low-valent main group element chemistry is challenging due to reactivity.
• Phosphine-functionalized ligands can provide unique stabilization.

Purpose of the Study:

• To synthesize and characterize germanium(II) and tin(II) complexes supported by a bis(diphenyl)phosphine functionalized β-diketiminato ligand (PNac).
• To investigate the coordination behavior and electronic stabilization provided by the PNac ligand.
• To explore the reactivity of these complexes, leading to cationic and low-valent species.

Main Methods:

• Synthesis of PNac ligand and its germanium/tin complexes.
• Chloride abstraction reactions to generate cationic species.
• Chemical decarbonylation to form phosphinidene complexes.
• Spectroscopic characterization (NMR, X-ray crystallography) of the resulting compounds.

Main Results:

• Successful synthesis of PNac-supported germanium(II) and tin(II) chloride compounds.
• Generation of cationic germyliumylidene and stannyliumylidene species stabilized by pendant phosphine arms.
• Formation of a "push-pull" stabilized phosphinidene complex via decarbonylation.
• Demonstration of the ligand's conformational flexibility and hemilability in stabilizing diverse species.

Conclusions:

• The PNac ligand provides a versatile and adaptable coordination environment for low-valent main group elements.
• The pendant phosphine arms play a crucial role in stabilizing reactive cationic and neutral species through Lewis acid-base interactions.
• This work expands the scope of ligand design for stabilizing unusual main group element compounds.