Reductive elimination of ethane from five-coordinate platinum(IV) alkyl complexes

Area of Science:

• Organometallic Chemistry
• Coordination Chemistry
• Platinum Chemistry

Background:

• Five-coordinate platinum(IV) complexes are key intermediates in organometallic transformations.
• Pyridylpyrrolide ligands offer tunable steric and electronic properties for metal complex stabilization.

Purpose of the Study:

• To synthesize and characterize novel five-coordinate platinum(IV) alkyl complexes with pyridylpyrrolide ligands.
• To investigate the thermal reactivity and decomposition pathways of these complexes.

Main Methods:

• Synthesis of platinum(IV) alkyl complexes.
• X-ray crystallography for structural determination.
• Thermolysis reactions in deuterated benzene with and without ethylene.
• Kinetic studies to elucidate reaction mechanisms.

Main Results:

• Successfully prepared two five-coordinate platinum(IV) complexes, (LX)PtMe(3), with distinct pyridylpyrrolide ligands (3a and 3b).
• X-ray structure confirmed a square-pyramidal geometry for complex 3a.
• Thermolysis with ethylene yielded cyclometalated platinum(II) ethylene complexes (4a and 4b) via reductive elimination of ethane and methane.
• Kinetic data for 3b supported a direct C-C reductive elimination mechanism from the Pt(IV) center.
• Thermolysis of 3a without ethylene led to the formation of a novel dinuclear platinum complex (5-d(6)).

Conclusions:

• The synthesized platinum(IV) complexes are reactive intermediates capable of undergoing reductive elimination.
• The reaction pathway involves direct C-C bond cleavage at the platinum center.
• The ligand structure and reaction conditions influence the decomposition products, allowing for the formation of diverse platinum species.