Isolable acetylene complexes of copper and silver.

Area of Science:

• Organometallic Chemistry
• Coordination Chemistry

Background:

• Copper(I) and silver(I) ions are crucial in acetylene transformations.
• Isolable metal-acetylene complexes are scarce, hindering detailed study.

Purpose of the Study:

• To synthesize and characterize novel π-acetylene complexes of Cu(I) and Ag(I).
• To investigate the structural and electronic properties of these complexes using various analytical techniques.

Main Methods:

• Synthesis of Cu(I) and Ag(I) complexes with pyrazole-based chelators under acetylene atmosphere.
• Isolation and characterization of crystalline complexes via X-ray crystallography.
• Spectroscopic analysis (13C NMR) and computational studies to understand metal-acetylene bonding.

Main Results:

• Stabilization of π-acetylene complexes with diverse coordination modes (κ2, κ3) and metal geometries (trigonal planar, tetrahedral).
• Observation of distinct coordination shifts in 13C NMR for Cu(I) and Ag(I) complexes.
• Experimental and computational evidence for stronger Cu-acetylene interactions compared to Ag.
• Development of a method to estimate C≡C bond distances from vibrational frequencies.

Conclusions:

• Pyrazole-based ligands effectively stabilize isolable Cu(I) and Ag(I) acetylene complexes.
• The study provides fundamental insights into metal-acetylene bonding and coordination chemistry.
• The findings contribute to understanding acetylene transformations catalyzed by transition metals.