Title: Probing the Ligand Exchange of N-Heterocyclic Carbene-Capped Ag₂S Nanocrystals with Amines and Carboxylic Acids

Abstract

N-Heterocyclic carbenes (NHCs) are versatile L-type ligands that have been shown to stabilize coinage metal chalcogenide nanocrystals, such as Ag₂S, remarkably well. However, very little research has been done on the interaction between NHC ligands and coinage metal chalcogenide nanocrystal surfaces and subsequent ligand exchange reactions. Herein, solution ¹H NMR methods were used to monitor ligand exchange reactions on stoichiometric Ag₂S nanocrystal platforms with various primary amine and carboxylic acid ligands. Despite the introduction of new ligands, the native NHC ligands remain tightly bound to the Ag₂S nanocrystal surface and are not displaced at room temperature. Primary amine and carboxylic acid ligands only demonstrated quantitative ligand exchange after heating the samples with excess incoming ligand, which implies a strong NHC-Ag binding energy. Density functional theory affirms that a model NHC ligand binds the strongest to a Ag₁₂S₆ cluster surface, followed by amine and carboxylic acid binding; computational analysis is therefore in line with the absence of NHC displacement observed in experiments. Here, both the bulky sterics of the C14-alkyl chains on the NHC and the strong binding energies of NHC to the Ag₂S surface contribute to the superior colloidal stability over conventional long-chain amine or carboxylic acid ligands (many monthsmore » vs. hours-to-days).« less

Authors:

Smock, Sara R. ^[1]; Alimento, Ryan ^[1]; Sharada, Shaama Mallikarjun  ^[1];

• Search DOE PAGES for author "Sharada, Shaama Mallikarjun"
• Search DOE PAGES for ORCID "0000-0001-7332-5373"

Brutchey, Richard L.  ^[1]

• Search DOE PAGES for author "Brutchey, Richard L."
• Search DOE PAGES for ORCID "0000-0002-7781-5596"

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+ Show Author Affiliations

1. Univ. of Southern California, Los Angeles, CA (United States)

Publication Date:

Sun Aug 15 00:00:00 EDT 2021

Research Org.:

Univ. of Southern California, Los Angeles, CA (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES); Graduate Research Fellowship Program of the National Science Foundation

OSTI Identifier:

1866260

Grant/Contract Number:  

SC0006812; FG02-11ER46826

Resource Type:

Accepted Manuscript

Journal Name:

Inorganic Chemistry

Additional Journal Information:

Journal Volume: 60; Journal Issue: 17; Journal ID: ISSN 0020-1669

Publisher:

American Chemical Society (ACS)

Country of Publication:

United States

Language:

English

Subject:

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; Organic acids; Ligands; Nanocrystals; Crystals; Ligand exchange