Time-resolved monitoring of dynamic self-assembly of Au(i)-thiolate coordination polymers

Abstract

Research interest in dynamic assemblies of coordination polymers (CPs) has been rising in recent years for the similarity with life systems in their self-adaptable morphologies and properties. However, monitoring of the assembly process and elucidating the nature for the morphological transformation are very challenging. Here, UV-Vis spectroscopy has been explored as a time-resolved method for monitoring the self-assembly of Au(I)-thiolate CPs in situ. Both step-wise and synergetic effects of the weak interactions in Au(I)-3-mercaptopropionic acid (MPA) CPs, such as H-bonding, coordination bonding, Au(I)-Au(I) interactions and static interactions have been found from the spectral fingerprints, which elucidated the driving forces for the unique morphological transformations from strings to lamellar structures. This work represents a breakthrough in that dynamic self-assembly behaviours can be explained by molecular interactions from molecular level evidences. Based on the spectral fingerprint-structure relationship the reversible and dynamic assembly of Au(I)-MPA CPs can be easily probed.

Manipulation of Inorganic Atomic‐Layer Networks by Solution‐Phase Co‐assembly

“…ATCP nanosheets have well‐resolved sharp UV/Vis absorption peaks, which are suggested to result from ligand‐to‐metal charge‐transfer (LMCT) and metal‐centred charge‐transfer (MCCT) transitions ,,. The absorption peaks can be an indication of the formation of nanosheets.…”

“…The above results show a non‐linear relationship between the rate of disappearance of nanosheets and the rate of generation of the gold nanoparticles, which suggest that the disappearance of nanosheets and generation of gold nanoparticles are two separate processes, and NaBH 4 may also play other roles besides as a reductant. Because our previous work has demonstrated that the Au I ‐MPA nanosheets are sensitive to pH value and show reversible assembly and disassembly behaviour on tuning the attraction and repulsion forces between MPA ligands, we turned our attention to the pH change after addition of NaBH 4 . The pH value rises from neutral and stabilizes at 9.8 because of the hydrolysis of NaBH 4 .…”

“…In contrast to most CPs, which utilize O‐ or N‐containing functional groups as donors to form coordination networks, the metal–S networks are formed through interatomic interactions, such as coordination bonds between metal ions and S atoms, as well as metallophilic interactions among noble metal ions (Figure b). The metal–S network is soft and vulnerable to the environment, and therefore it is possible to modulate the metal–S network by changing the substituent on S through multiligand co‐assembly. Although a series of metal–thiolate lamellar CP structures have been prepared with different thiol ligands, no such attempt has been made.…”

“…Previously, we succeeded in synthesizing colloidal Au I –thiolate coordination polymer (ATCP) nanosheets in water with 3‐mercaptopropionic acid (MPA) as ligand (denoted Au I ‐MPA) . In this work, we explored the possibility of introducing a second ligand in the assemblies and studied how these organic ligands tune the properties of the Au I –S inorganic network.…”

Nanoscale Lacing by Electrons

“…The solution color turned from yellow to brown, indicating that Au(III) ions were reduced to Au(0), forming CTAB‐capped Au nanoparticles or nanoclusters. After a controlled reaction time (typically ranging from 10 min to 40 h to form NPs of 2–8 nm in diameter), the Au NPs were etched for preparing Au(I)‐SR . 100 µL MPA was injected into the solution of preformed CTAB‐capped Au nanoparticles under stirring, and the solution then was incubated for 15 h under stirring to produce Au(I)‐thiolate species.…”