Aromatic cis-capping ligands reconfigure a coordination cage system for allosterically controlled BODIPY uptake and release
- 1College of Science and Engineering
- 2Flinders University
Abstract
Biological allostery enables precise molecular recognition and complex function, yet emulating this phenomenon in aqueous synthetic systems remains a significant challenge. Here, we demonstrate that remote cis-capping ligand (L C ) effects can reconfigure a dynamic metal-organic cage (MOC) system for pronounced allosteric guest uptake and release in water. Incorporation of bipyridine (bpy) as L C into a (Pd-L C ) 6 TImB 4 MOC (TImB = 1,3,5-tri(1H-imidazol-1-yl)benzene) shifts the isomer preference from a tube, favored when L C = tetramethylethylenediamine (tmeda), to a capsule-dominated ensemble, while also inducing axial elongation of the minor tube isomer. DFT calculations reveal two remote effects of bpy: (i) TImB planarization is more readily accommodated – a conformation required for capsule isomer; (ii) a broader range of Pd-imidazole rotations are permittable, enabling the minor tube isomer to elongate. A consequence of these effects is a capsule dominated state that hinders the encapsulation of linear aromatic guests, including a water-insoluble BODIPY fluorophore. We show that SO 4 2‒ acts as an exohedral allosteric effector, triggering upregulation of a BODIPY-binding tube state and a pronounced increase in emission. Removal of the effector anion regenerates the non-binding state, promoting slow release of the BODIPY cargo; a process which operates for other linear guests. This work establishes a general strategy based on remote ligand effects and an allosteric anion effector to control molecular catch-and-release in water.
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BibTeX
@misc{virtue2026aromatic,
title = {{Aromatic cis-capping ligands reconfigure a coordination cage system for allosterically controlled BODIPY uptake and release}},
author = {Jemma I. Virtue and Asja A. Kroeger and Martin R. Johnston and Michelle L. Coote and Witold M. Bloch},
howpublished = {ChemRxiv},
year = {2026},
month = oct,
doi = {10.26434/chemrxiv.15010432/v1},
url = {https://chemrxiv.org/doi/full/10.26434/chemrxiv.15010432/v1},
note = {CC BY},
}
RIS
TY - UNPB
TI - Aromatic cis-capping ligands reconfigure a coordination cage system for allosterically controlled BODIPY uptake and release
AU - Jemma I. Virtue
AU - Asja A. Kroeger
AU - Martin R. Johnston
AU - Michelle L. Coote
AU - Witold M. Bloch
PY - 2026
DA - 2026/10/13
PB - ChemRxiv
DO - 10.26434/chemrxiv.15010432/v1
UR - https://chemrxiv.org/doi/full/10.26434/chemrxiv.15010432/v1
AB - Biological allostery enables precise molecular recognition and complex function, yet emulating this phenomenon in aqueous synthetic systems remains a significant challenge. Here, we demonstrate that remote cis-capping ligand (L C ) effects can reconfigure a dynamic metal-organic cage (MOC) system for pronounced allosteric guest uptake and release in water. Incorporation of bipyridine (bpy) as L C into a (Pd-L C ) 6 TImB 4 MOC (TImB = 1,3,5-tri(1H-imidazol-1-yl)benzene) shifts the isomer preference from a tube, favored when L C = tetramethylethylenediamine (tmeda), to a capsule-dominated ensemble, while also inducing axial elongation of the minor tube isomer. DFT calculations reveal two remote effects of bpy: (i) TImB planarization is more readily accommodated – a conformation required for capsule isomer; (ii) a broader range of Pd-imidazole rotations are permittable, enabling the minor tube isomer to elongate. A consequence of these effects is a capsule dominated state that hinders the encapsulation of linear aromatic guests, including a water-insoluble BODIPY fluorophore. We show that SO 4 2‒ acts as an exohedral allosteric effector, triggering upregulation of a BODIPY-binding tube state and a pronounced increase in emission. Removal of the effector anion regenerates the non-binding state, promoting slow release of the BODIPY cargo; a process which operates for other linear guests. This work establishes a general strategy based on remote ligand effects and an allosteric anion effector to control molecular catch-and-release in water.
ER -