σ-GeH and Germyl Cationic Pt(II) Complexes

Area of Science:

• Organometallic Chemistry
• Inorganic Chemistry
• Materials Science

Background:

• Low electron count platinum(II) complexes featuring N-heterocyclic carbene (NHC) ligands are known for their unique reactivity.
• Understanding the activation of Group 14 element hydrides by transition metals is crucial for catalysis and synthesis.

Purpose of the Study:

• To investigate the reaction of low electron count Pt(II) complexes with tertiary hydrogermanes.
• To characterize the resulting platinum-germyl derivatives and any transient intermediates.
• To elucidate the bonding interactions and reaction mechanisms involved.

Main Methods:

• Reactions conducted at room temperature and low temperatures.
• Spectroscopic characterization using Nuclear Magnetic Resonance (NMR) spectroscopy.
• X-ray diffraction studies for structural determination.
• Density Functional Theory (DFT) calculations for mechanistic insights.

Main Results:

• Pt(II) complexes react with tertiary hydrogermanes to yield 14-electron platinum(II) germyl complexes.
• Low-temperature NMR detected and characterized transient σ-GeH intermediates.
• X-ray diffraction and DFT calculations revealed significant electronic interactions between the platinum center and the Ge-H bond, including donation and backdonation.
• Reactivity with primary and secondary hydrogermanes contrasts with silane chemistry, favoring Pt-Ge/C-H bond formation.

Conclusions:

• The reaction pathway involves the formation and characterization of novel platinum-germyl complexes and intermediates.
• Detailed electronic structure analysis provides insights into the nature of the metal-hydride bond activation.
• The observed reactivity highlights the distinct behavior of hydrogermanes compared to hydrosilanes in reactions with these Pt(II) complexes.