skip to main content


Title: Stable Cuprous Hydroxide Nanostructures by Organic Ligand Functionalization
Abstract

Copper compounds have been extensively investigated for diverse applications. However, studies of cuprous hydroxide (CuOH) have been scarce due to structural metastability. Herein, a facile, wet‐chemistry procedure is reported for the preparation of stable CuOH nanostructures via deliberate functionalization with select organic ligands, such as acetylene and mercapto derivatives. The resulting nanostructures are found to exhibit a nanoribbon morphology consisting of small nanocrystals embedded within a largely amorphous nanosheet‐like scaffold. The acetylene derivatives are found to anchor onto the CuOH forming CuC linkages, whereas CuS interfacial bonds are formed with the mercapto ligands. Effective electronic coupling occurs at the ligand‐core interface in the former, in contrast to mostly non‐conjugated interfacial bonds in the latter, as manifested in spectroscopic measurements and confirmed in theoretical studies based on first principles calculations. Notably, the acetylene‐capped CuOH nanostructures exhibit markedly enhanced photodynamic activity in the inhibition of bacteria growth, as compared to the mercapto‐capped counterparts due to a reduced material bandgap and effective photocatalytic generation of reactive oxygen species. Results from this study demonstrate that deliberate structural engineering with select organic ligands is an effective strategy in the stabilization and functionalization of CuOH nanostructures, a critical first step in exploring their diverse applications.

 
more » « less
Award ID(s):
1848841 2003685
NSF-PAR ID:
10386711
Author(s) / Creator(s):
 ;  ;  ;  ;  ;  ;  ;  ;  ;  ;  ;  ;  ;  ;  ;  
Publisher / Repository:
Wiley Blackwell (John Wiley & Sons)
Date Published:
Journal Name:
Advanced Materials
Volume:
35
Issue:
8
ISSN:
0935-9648
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. Abstract

    Surface functionalization of semiconductor nanoparticles plays a significant role in the manipulation of the nanoparticle physicochemical properties and diverse applications. Conventional points of anchor involve mercapto, carboxyl and phenol moieties, forming largely nonconjugated interfacial linkages. In this personal account, we summarize recent progress in surface functionalization of semiconductor nanoparticles with olefin and acetylene derivatives, where the formation of conjugated interfacial bonds leads to ready manipulation of the nanoparticle optical and electronic properties, by using Si and TiO2nanoparticles as the illustrating examples. Finally, a perspective is included where the promises and challenges of structural engineering of semiconductor nanoparicles are highlighted.

     
    more » « less
  2. Abstract

    Janus nanoparticles capped with a hydrophobic and hydrophilic hemisphere of mercapto ligands can self‐assemble into hollow, emulsion‐like nanostructures in controlled media. As the nanoparticle emulsions are chiroptically active exhibiting a plasmonic circular dichroism absorption in the visible range, they can be exploited as a unique chiral nanoreactor by selective encapsulation ofd‐enantiomer into the water phase of the water‐in‐oil emulsions for directional functionalization of the nanoparticles and endow the resulting nanoparticles with select chirality. This is demonstrated in the present study with gold Janus nanoparticles functionalized with (hydrophobic) hexanethiolates and (hydrophilic) 3‐mercapto‐1,2‐propandiol, andd,l‐cysteine is used as the molecular probe. Experimental results demonstrate thatd‐cysteine is the preferred enantiomers entrapped within the nanoparticle emulsions, where the ensuing ligand exchange reaction is initially confined to the hydrophilic face of the Janus nanoparticles. This suggests that with a deliberate control of the reaction time, chiral Janus nanoparticles can be readily prepared by ligand exchange reactions even with a racemic mixture of ligands.

     
    more » « less
  3. Chiral nanostructures have been attracting extensive interest in recent years primarily because of the unique materials properties that can be exploited for diverse applications. In this study, gold Janus nanoparticles, with hexanethiolates and 3-mercapto-1,2-propanediol segregated on the two hemispheres of the metal cores (dia. 2.7 ± 0.4 nm), self-assembled into vesicle-like, hollow nanostructures in both water and organic media, and exhibited apparent plasmonic circular dichroism (PCD) absorption in the visible range. This was in contrast to individual Janus nanoparticles, bulk-exchange nanoparticles where the two ligands were homogeneously mixed on the nanoparticle surface, or nanoparticles capped with only one kind of ligand. The PCD signals were found to become intensified with increasing coverage of the 3-mercapto-1,2-propanediol ligands on the nanoparticle surface. This was accounted for by the dipolar property of the structurally asymmetrical Janus nanoparticles, and theoretical simulations based on first principles calculations showed that when the nanoparticle dipoles self-assembled onto the surface of a hollow sphere, a vertex was formed which gave rise to the unique chiral characteristics. The resulting chiral nanoparticle vesicles could be exploited for the separation of optical enantiomers, as manifested in the selective identification and separation of d -alanine from the l -isomer. 
    more » « less
  4. A two-step route to strongly absorbing and efficiently orange to deep red fluorescent, doubly B/N-doped, ladder-type pyrrolo[3,2- b ]pyrroles has been developed. We synthesize and study a series of derivatives of these four-coordinate boron-containing, nominally quadrupolar materials, which mostly exhibit one-photon absorption in the 500–600 nm range with the peak molar extinction coefficients reaching 150 000, and emission in the 520–670 nm range with the fluorescence quantum yields reaching 0.90. Within the family of these ultrastable dyes even small structural changes lead to significant variations of the photophysical properties, in some cases attributed to reversal of energy ordering of alternate-parity excited electronic states. Effective preservation of ground-state inversion symmetry was evidenced by very weak two-photon absorption (2PA) at excitation wavelengths corresponding to the lowest-energy, strongly one-photon allowed purely electronic transition. π-Expanded derivatives and those possessing electron-donating groups showed the most red-shifted absorption- and emission spectra, while displaying remarkably high peak 2PA cross-section ( σ 2PA ) values reaching ∼2400 GM at around 760 nm, corresponding to a two-photon allowed higher-energy excited state. At the same time, derivatives lacking π-expansion were found to have a relatively weak 2PA peak centered at ca. 800–900 nm with the maximum σ 2PA ∼50–250 GM. Our findings are augmented by theoretical calculations performed using TD-DFT method, which reproduce the main experimental trends, including the 2PA, in a nearly quantitative manner. Electrochemical studies revealed that the HOMO of the new dyes is located at ca . −5.35 eV making them relatively electron rich in spite of the presence of two B − –N + dative bonds. These dyes undergo a fully reversible first oxidation, located on the diphenylpyrrolo[3,2- b ]pyrrole core, directly to the di(radical cation) stage. 
    more » « less
  5. A facile methodology to prepare N-heterocyclic carbene (NHC)-terminated polymers as surface ligands to functionalize gold nanoparticles (AuNPs) is reported. Our method highlights a mild, aerobic synthesis of NHC-functionalized polymers and a simple ligand exchange approach towards surface modification of AuNPs prepared in aqueous solution. Two methods, including end-group functionalization of halogen-ended polymers from a conventional atom transfer radical polymerization (ATRP) and post-polymerization functionalization of imidazole-containing polymers using imidazole-containing ATRP initiator, have been investigated to prepare imidazolium-ended polymers. Using a one-step, oxygen and moisture tolerant procedure, the polymer–NHC–Cu( i ) species can be synthesized from imidazolium-ended polymers and readily bind to citrate-capped AuNPs likely through transmetalation, yielding robust polymer-stabilized AuNPs. Our synthetic method significantly simplifies the preparation and use of polymer–NHC ligands for surface functionalization of metal NPs. Our methodology is general and potentially applicable to any polymers prepared by ATRP to functionalize metal NPs via NHC–metal coordination; therefore, it will likely broaden the applications of polymer–NHC ligands for metal nanoparticles in the fields of catalysis and nanomedicine. 
    more » « less