Synthesis and Properties of Medium-Sized cis,trans-Cycloocta-1,3-diene-Pt(II) Complexes

Area of Science:

• Organometallic Chemistry
• Strained Ring Chemistry

Background:

• cis,trans-Cycloocta-1,3-dienes (TCODs) are highly strained and difficult to isolate due to rapid 4π-electrocyclization.
• Elusive strained alkenes present challenges in synthetic chemistry.

Purpose of the Study:

• To achieve the first stable isolation of cis,trans-cycloocta-1,3-dienes (TCODs).
• To characterize TCOD-metal complexes and explore their reactivity.

Main Methods:

• Synthesis of platinum(II) complexes incorporating TCODs.
• X-ray crystallography for structural determination.
• Ligand exchange and desilylation reactions to study reactivity.

Main Results:

• Stable isolation of cis,trans-cycloocta-1,3-dienes as Pt(II) complexes.
• X-ray crystallography revealed significant bond elongation and dihedral distortion in the TCOD ligand.
• Pt-TCOD complexes demonstrated reactivity including ligand exchange, desilylation to π-allyl species, and enantioselective decomplexation.

Conclusions:

• Pt-TCOD complexes are effective isolable surrogates for elusive strained alkenes.
• This work provides a foundation for new developments in organometallic chemistry and strained-ring synthesis.
• Enantioselective decomplexation opens avenues for asymmetric synthesis.