From Rim to Core: Nitrile Coordination Creates an Electronic Gradient across Cu12 Nanocluster Nodes for CO2-to-Formate Electrosynthesis
- 1Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Japan, 980-8577
- 2Department of Materials Science and Metallurgical Engineering
- 3Indian Institute of Technology
Abstract
Atomically precise copper nanoclusters offer an opportunity to program catalysis across individual metal positions, yet reticulation has largely been used to stabilize clusters rather than differentiate them electronically. Here, nitrile coordination converts a Cu12S9 nanocluster node into a radially polarized catalytic ensemble in Cu12TPN MOF. Single-crystal analysis resolves a thiolate-supported Cu12 architecture whose four terephthalonitrile linkers selectively address peripheral Cu sites. Bader analysis reveals an electronic gradient from electron-deficient nitrile-bound rim sites (~+0.57 |e|) to an electron-rich Cu–S/Cu interior (~+0.32–0.37 |e|). This coordination-encoded asymmetry translates directly into CO2 reduction, delivering 63.32% Faradaic efficiency for HCOOH with negligible CO formation. Density functional theory identifies a 0.91 eV energetic separation favoring O-bound *OCOH over *COOH at the pathway bifurcation, while H adsorption remains unfavorable. Post-electrolysis spectroscopy confirms persistence of the cluster-derived environment. These results establish reticulation as an electronic programming strategy within, rather than merely around, atomically precise nanocluster nodes. Atomically precise metal nanoclusters (NCs) occupy an unusual catalytic regime in which composition, metalmetal connectivity, ligand coordination, and individual surface sites can all be resolved at the atomic level.1-24 Unlike nanoparticles with distributed surface sites, NCs provide finite multinuclear ensembles in which structural and electronic perturbations can be traced from specific coordination events to catalytic consequences. Copper nanoclusters are especially attractive in this regard because the adaptable coordination chemistry of Cu(I), flexible Cu–S bonding, and short Cu···Cu contacts permit substantial redistribution of geometry and electron density within a single cluster.25-42 Yet this same adaptability makes it difficult to preserve atomically defined Cu ensembles under catalytic conditions.
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BibTeX
@misc{sreelakshmi2026from,
title = {{From Rim to Core: Nitrile Coordination Creates an Electronic Gradient across Cu12 Nanocluster Nodes for CO2-to-Formate Electrosynthesis}},
author = {Sreelakshmi and Tsukasa Irie and Tokuhisa Kawawaki and Milan Kumar Jena and Saikat Das and Yuichi Negishi},
howpublished = {ChemRxiv},
year = {2026},
month = sep,
doi = {10.26434/chemrxiv.15009115/v1},
url = {https://chemrxiv.org/doi/full/10.26434/chemrxiv.15009115/v1},
note = {CC BY},
}
RIS
TY - UNPB
TI - From Rim to Core: Nitrile Coordination Creates an Electronic Gradient across Cu12 Nanocluster Nodes for CO2-to-Formate Electrosynthesis
AU - Sreelakshmi
AU - Tsukasa Irie
AU - Tokuhisa Kawawaki
AU - Milan Kumar Jena
AU - Saikat Das
AU - Yuichi Negishi
PY - 2026
DA - 2026/09/20
PB - ChemRxiv
DO - 10.26434/chemrxiv.15009115/v1
UR - https://chemrxiv.org/doi/full/10.26434/chemrxiv.15009115/v1
AB - Atomically precise copper nanoclusters offer an opportunity to program catalysis across individual metal positions, yet reticulation has largely been used to stabilize clusters rather than differentiate them electronically. Here, nitrile coordination converts a Cu12S9 nanocluster node into a radially polarized catalytic ensemble in Cu12TPN MOF. Single-crystal analysis resolves a thiolate-supported Cu12 architecture whose four terephthalonitrile linkers selectively address peripheral Cu sites. Bader analysis reveals an electronic gradient from electron-deficient nitrile-bound rim sites (~+0.57 |e|) to an electron-rich Cu–S/Cu interior (~+0.32–0.37 |e|). This coordination-encoded asymmetry translates directly into CO2 reduction, delivering 63.32% Faradaic efficiency for HCOOH with negligible CO formation. Density functional theory identifies a 0.91 eV energetic separation favoring O-bound *OCOH over *COOH at the pathway bifurcation, while H adsorption remains unfavorable. Post-electrolysis spectroscopy confirms persistence of the cluster-derived environment. These results establish reticulation as an electronic programming strategy within, rather than merely around, atomically precise nanocluster nodes. Atomically precise metal nanoclusters (NCs) occupy an unusual catalytic regime in which composition, metalmetal connectivity, ligand coordination, and individual surface sites can all be resolved at the atomic level.1-24 Unlike nanoparticles with distributed surface sites, NCs provide finite multinuclear ensembles in which structural and electronic perturbations can be traced from specific coordination events to catalytic consequences. Copper nanoclusters are especially attractive in this regard because the adaptable coordination chemistry of Cu(I), flexible Cu–S bonding, and short Cu···Cu contacts permit substantial redistribution of geometry and electron density within a single cluster.25-42 Yet this same adaptability makes it difficult to preserve atomically defined Cu ensembles under catalytic conditions.
ER -