The Missing Parent Compound [(C₅ H₅ )Fe(η⁵ -P₅ )]: Synthesis, Characterization, Coordination Behavior and...

Area of Science:

• Organometallic Chemistry
• Coordination Chemistry
• Materials Science

Background:

• Pentaphosphaferrocenes are a class of organometallic compounds with potential applications in materials science.
• The synthesis and characterization of the parent compound [CpFe(η⁵-P₅)] were previously lacking, hindering further exploration of this family.
• Understanding the coordination behavior of such novel ligands is crucial for designing new functional materials.

Purpose of the Study:

• To synthesize and comprehensively characterize the parent compound [CpFe(η⁵-P₅)] (1b).
• To investigate the coordination chemistry of [CpFe(η⁵-P₅)] with copper(I) halides.
• To explore the formation of novel coordination polymers and supramolecular structures.

Main Methods:

• Thermolysis of [CpFe(CO)₂]₂ with P₄ in diisopropylbenzene.
• Characterization techniques including NMR spectroscopy, single crystal X-ray diffraction, cyclic voltammetry, and DFT computations.
• Exploration of coordination behavior with CuI, CuBr, and CuCl.

Main Results:

• Successful synthesis and characterization of the parent pentaphosphaferrocene compound [CpFe(η⁵-P₅)] (1b).
• Discovery of unprecedented 2D polymeric networks with copper(I) halides: [{CpFe(η⁵:1:1:1:1-P₅)}Cu₂(μ-X)₂]n (2a, 2b) and [{CpFe(η⁵:1:1-P₅)}Cu(μ-I)]n (3).
• Formation of the first cyclo-P₅-containing 3D coordination polymer [{CpFe(η⁵:1:1-P₅)}Cu(μ-I)]n (4) and nano-sized supramolecular fullerene-like spheres [CpFe(η⁵-P₅)]@[{Cp*Fe(η⁵-P₅)}₁₂ (CuX)₂₀₋ₙ] (5a-5c).

Conclusions:

• The parent pentaphosphaferrocene compound is accessible and exhibits rich coordination chemistry.
• This study expands the structural diversity of pentaphosphaferrocene-based coordination polymers and supramolecular assemblies.
• The findings open new avenues for designing novel phosphorus-containing inorganic-organic hybrid materials.