Selective Functionalization with Organophosphite Ligands of Atomically Precise Platinum Chini Clusters.

Area of Science:

• Organometallic Chemistry
• Coordination Chemistry
• Materials Science

Background:

• Homoleptic platinum carbonyl clusters, [Pt_3n(CO)_6n]^2-, serve as precursors for synthesizing more complex platinum cluster species.
• The substitution of carbonyl (CO) ligands with phosphite ligands (P(OR)₃) is a key strategy for modifying the structure and properties of platinum clusters.

Purpose of the Study:

• To synthesize and characterize novel heteroleptic platinum carbonyl clusters with varying phosphite ligands.
• To investigate the substitution patterns and structural transformations of platinum clusters upon reaction with phosphites.
• To elucidate the solution-state structures and solid-state molecular architectures of the synthesized clusters.

Main Methods:

• Reaction of homoleptic [Pt_3n(CO)_6n]^2- clusters with phosphite ligands P(OR)₃ (R = Me, Et, Ph).
• Spectroscopic characterization using FT-IR, ESI-MS, ¹H NMR, and ³¹P{¹H} NMR spectroscopy.
• Structural determination of selected clusters via single-crystal X-ray diffraction (SC-XRD) and computational studies.

Main Results:

• Successful synthesis of heteroleptic clusters [Pt_3n(CO)_6n-x{P(OR)₃}_x]^2- (n=3-5, x=1-2) with P(OPh)₃, P(OMe)₃, and P(OEt)₃.
• Observation that 1-2 CO ligands can be selectively replaced by P(OR)₃, while a third substitution leads to Pt₃-triangle elimination and smaller cluster formation.
• Determination of molecular structures for several novel platinum clusters, revealing insights into torsional and positional isomerism.

Conclusions:

• The controlled substitution of CO ligands in homoleptic platinum clusters with phosphites provides a versatile route to heteroleptic platinum carbonyl clusters.
• The study elucidates the reactivity patterns and structural diversity of platinum clusters, influenced by the electronic properties of phosphite ligands.
• The findings contribute to a deeper understanding of the synthesis, structure, and stability of polynuclear platinum carbonyl cluster compounds.