A Dinucleating β-Thio-δ-Diiminate Ligand Enables Metal-Dependent CO2 Reactivity in Homo- and Heterobimetallic Zn and Cu Complexes
- 1School of Chemical, Environmental and Earth Sciences, University of Leicester, University Road, Leicester, UK, LE1 7RH
- 2School of Chemistry
- 3Trinity College Dublin, The University of Dublin
Abstract
Herein, we investigate the β-thio-δ-diimine (BTDDI) ligand, recently reported as a sulfur containing analogue of the established BODDI framework, as a platform for mono- and bimetallic Cu(I) and Zn(II) chemistry. Sequential metalation enables selective access to homo- and heterobimetallic complexes, including the first structurally characterised Cu/Zn derivative of this ligand class. Replacement of the central oxygen donor by sulfur expands the dinuclear framework, resulting in significantly increased metal–metal separations. The reactivity of these complexes towards CO 2 is strongly dependent on both metal identity and nuclearity: monometallic Cu(I) and Zn(II) complexes and the homobimetallic Cu(I) analogue are unreactive, whereas the Cu/Zn and di-Zn complexes undergo CO 2 activation. The di-Zn complex undergoes selective C–C bond formation at the γ-position of the ligand backbone to give a reversibly formed carboxylate-containing product featuring an unusual tripodal [N,S,O] donor motif. Isotopic labelling, spectroscopic and structural studies establish incorporation of CO 2 into the ligand framework, while DFT calculations reveal substantially lower barriers to γ-C insertion for the bimetallic complexes and identify Zn(II) as a key contributor to stabilisation of the resulting carboxylate through Zn–O interactions and subsequent dimerisation. These results establish a mode of CO 2 activation in which ligand-centred reactivity is coupled to metal-centred substrate stabilisation, with metal identity and nuclearity determining the outcome of the reaction.
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BibTeX
@misc{allen2026dinucleating,
title = {{A Dinucleating β-Thio-δ-Diiminate Ligand Enables Metal-Dependent CO2 Reactivity in Homo- and Heterobimetallic Zn and Cu Complexes}},
author = {Jamie Allen and Diney S. Shanfrezan and Grace E. Linford-Wood and Tobias Krämer and Alexander F. R. Kilpatrick},
howpublished = {ChemRxiv},
year = {2026},
month = sep,
doi = {10.26434/chemrxiv.15009332/v1},
url = {https://chemrxiv.org/doi/full/10.26434/chemrxiv.15009332/v1},
note = {CC BY},
}
RIS
TY - UNPB
TI - A Dinucleating β-Thio-δ-Diiminate Ligand Enables Metal-Dependent CO2 Reactivity in Homo- and Heterobimetallic Zn and Cu Complexes
AU - Jamie Allen
AU - Diney S. Shanfrezan
AU - Grace E. Linford-Wood
AU - Tobias Krämer
AU - Alexander F. R. Kilpatrick
PY - 2026
DA - 2026/09/23
PB - ChemRxiv
DO - 10.26434/chemrxiv.15009332/v1
UR - https://chemrxiv.org/doi/full/10.26434/chemrxiv.15009332/v1
AB - Herein, we investigate the β-thio-δ-diimine (BTDDI) ligand, recently reported as a sulfur containing analogue of the established BODDI framework, as a platform for mono- and bimetallic Cu(I) and Zn(II) chemistry. Sequential metalation enables selective access to homo- and heterobimetallic complexes, including the first structurally characterised Cu/Zn derivative of this ligand class. Replacement of the central oxygen donor by sulfur expands the dinuclear framework, resulting in significantly increased metal–metal separations. The reactivity of these complexes towards CO 2 is strongly dependent on both metal identity and nuclearity: monometallic Cu(I) and Zn(II) complexes and the homobimetallic Cu(I) analogue are unreactive, whereas the Cu/Zn and di-Zn complexes undergo CO 2 activation. The di-Zn complex undergoes selective C–C bond formation at the γ-position of the ligand backbone to give a reversibly formed carboxylate-containing product featuring an unusual tripodal [N,S,O] donor motif. Isotopic labelling, spectroscopic and structural studies establish incorporation of CO 2 into the ligand framework, while DFT calculations reveal substantially lower barriers to γ-C insertion for the bimetallic complexes and identify Zn(II) as a key contributor to stabilisation of the resulting carboxylate through Zn–O interactions and subsequent dimerisation. These results establish a mode of CO 2 activation in which ligand-centred reactivity is coupled to metal-centred substrate stabilisation, with metal identity and nuclearity determining the outcome of the reaction.
ER -