Nanomechanical Investigations of Crystals of Copper Nanocluster Isomorphs: Enhanced Hardness of the Low-Density Analogue

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61388980%3A_____%2F25%3A00605407" target="_blank" >RIV/61388980:_____/25:00605407 - isvavai.cz</a>

Result on the web

<a href="https://doi.org/10.1021/acs.chemmater.4c03265" target="_blank" >https://doi.org/10.1021/acs.chemmater.4c03265</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1021/acs.chemmater.4c03265" target="_blank" >10.1021/acs.chemmater.4c03265</a>

Result language

angličtina

Original language name

Nanomechanical Investigations of Crystals of Copper Nanocluster Isomorphs: Enhanced Hardness of the Low-Density Analogue

Original language description

Atomically precise cluster crystals, with constituent units composed of tens to hundreds of atoms, are important for the construction of miniaturized solid-state devices. Understanding the mechanical characteristics of such crystals is crucial for these applications. In this study, we focused on the nanomechanical properties of crystals of two isomorphic copper nanoclusters (Cu4L4), protected by ortho-carborane-9-thiol, Cu4(oCBT)4, and meta-carborane-9-thiol, Cu4(mCBT)4. These two clusters possess identical square planar Cu4 cores embedded in butterfly-shaped Cu4S4 staples. Load-displacement measurements indicated that the crystals of Cu4(oCBT)4 (hardness of similar to 534.31 MPa) were harder than those of Cu4(mCBT)4 (hardness of similar to 335.49 MPa). Despite their lower density, crystals of Cu4(oCBT)4 demonstrated increased hardness, owing to the presence of locked slanted layers that efficiently interacted with each other through various short contact supramolecular interactions. During indentation studies, multiple “pop-in” events were observed for the crystals of both clusters, suggesting the dislocation of molecular layers within the crystal lattice. Dynamic mechanical analysis conducted at different loading frequencies indicated that crystals of Cu4(oCBT)4 have a higher storage modulus than Cu4(mCBT)4. Both the crystals are thermally robust, as evident from thermogravimetric analysis and attenuated total reflection-IR analysis. Using density functional theory, we calculated Young's modulus (E r) for both crystals at 1 and 2% strain and found that the high-density isomorph had a lower E r, consistent with experimental data showing E r of Cu4(oCBT)4 and Cu4(mCBT)4 to be 9.79 and 8.54 GPa, respectively. These findings highlight the significant role of subtle structural differences in governing the nanomechanical behavior of isomorphic cluster crystals, paving the way for their rational design in advanced solid-state device applications.

Czech name

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Czech description

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Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

—

OECD FORD branch

10402 - Inorganic and nuclear chemistry

Project

—

Continuities

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2025

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Chemistry of Materials

ISSN

0897-4756

e-ISSN

1520-5002

Volume of the periodical

37

Issue of the periodical within the volume

3

Country of publishing house

US - UNITED STATES

Number of pages

13

Pages from-to

1284-1296

UT code for WoS article

001403521400001

EID of the result in the Scopus database

2-s2.0-85216254466