Self-assembly processes of 2D Au(I)-S(CH₂)₂COOH lamellae

Area of Science:

• Materials Science
• Nanotechnology
• Coordination Chemistry

Background:

• Determining the assembled structure of gold(I)-thiolate linear coordination polymers is difficult due to poor crystallinity.
• This lack of crystallinity hinders understanding of their molecular-level assembly processes.

Purpose of the Study:

• To elucidate the molecular assembly processes of gold(I)-thiolate linear coordination polymers.
• To understand the formation of two-dimensional (2D) lamellae structures.
• To develop methods for synthesizing tunable 2D Au(I)-MPA lamellae.

Main Methods:

• Cryogenic transmission electron microscopy (cryo-TEM) was used to obtain selected area electron diffraction (SAED) patterns.
• SAED patterns of 2D Au(I)-S(CH2)2COOH (Au(I)-MPA) lamellae were analyzed.
• Comparison with the crystal structure of Ag(I)-MPA (solved by powder X-ray diffraction) aided in proposing a packing mode.

Main Results:

• SAED patterns provided insights into the packing mode of Au(I)-MPA chains within the 2D structure.
• Multi-step self-assembly processes, involving aggregation and crystallization of 1D pre-assemblies, were disclosed.
• Tunable 2D Au(I)-MPA lamellae with controlled sizes and crystallinity were synthesized via kinetic control.

Conclusions:

• The study reveals the multi-step self-assembly pathway leading to 2D Au(I)-MPA lamellae.
• The findings explain the challenges in synthesizing large single crystals of these materials.
• Kinetic control offers a route to synthesize size- and crystallinity-tunable 2D Au(I)-MPA lamellae.