Metallophilic interactions in silver(I) dicyanoaurate complexes.

Area of Science:

• Coordination Chemistry
• Supramolecular Chemistry
• Materials Science

Background:

• Gold(I) and silver(I) complexes are of interest due to their unique electronic properties and potential applications.
• Metallophilic interactions, such as aurophilic (Au-Au) and argentophilic (Ag-Ag) interactions, significantly influence the structure and properties of these complexes.
• The role of ancillary ligands and solvent effects in directing the self-assembly and structural diversity of heteronuclear gold-silver complexes requires further investigation.

Purpose of the Study:

• To synthesize and characterize novel gold(I)-silver(I) complexes using 2-(2-pyridyl)-1,8-naphthyridine (pyNP) and terpyridine (terpy) ligands.
• To investigate the structural diversity and the influence of solvent on the formation of these complexes, particularly focusing on metallophilic interactions.
• To explore the solution behavior and electronic properties of the synthesized complexes using computational methods.

Main Methods:

• Synthesis of four new gold(I)-silver(I) complexes: [Ag(pyNP)(Au(CN)2)]2 (1), [Ag2Au2(μ-CN)2(CN)2(pyNP)2] (2), [Ag2Au(μ-CN)2(terpy)2][Au(CN)2] (3), and [Ag4Au4(μ-CN)8(terpy)2(py)] (4).
• Structural characterization using X-ray crystallography and vibrational spectroscopy.
• Solution chemistry studies using electrospray ionization mass spectrometry (ESI-MS) and Density Functional Theory (DFT) calculations.

Main Results:

• Complexes 1 and 2, structural isomers obtained from different solvents, exhibit distinct coordination modes of the Au(CN)2- anion and varying metallophilic interactions.
• Complex 3 features a bridging Au(CN)2- anion and an infinite array of gold atoms with aurophilic interactions (3.415 Å).
• Complex 4 displays a 3D architecture driven by significant Au-Au and Au-Ag metallophilic interactions; DFT calculations elucidated these interactions and π-stacking effects.

Conclusions:

• The study successfully synthesized and characterized four novel gold(I)-silver(I) complexes, showcasing diverse structural motifs.
• Solvent choice plays a crucial role in determining the coordination behavior and the presence/absence of metallophilic interactions.
• DFT calculations provide valuable insights into the nature of Ag-Au interactions and their contribution to crystal packing, enhancing the understanding of these complex systems.