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Updated: Jan 13, 2026
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Heterogeneous Removal of Water-Soluble Ruthenium Olefin Metathesis Catalyst from Aqueous Media Via Host-Guest Interaction
Published on: August 23, 2018
8.3K
Cation-Dependent Multilayered Host-Guest Assemblies Formed by a Xanthene-Based Dinuclear Nickel(II) Macrocycle
Shigehisa Akine1,2, Masato Nakano2, Yoko Sakata3
1Nano Life Science Institute (WPI-NanoLSI), Kanazawa University, Kakuma-machi, Kanazawa, Japan.
Chemistry (Weinheim an Der Bergstrasse, Germany)
|January 7, 2026
Summary
This study synthesized a nickel(II) macrocyclic host for alkali metal ion recognition. The host forms distinct sandwich complexes with sodium versus larger ions like potassium, demonstrating size-dependent aggregation behavior for supramolecular assembly.
Area of Science:
- Supramolecular Chemistry
- Coordination Chemistry
- Materials Science
Background:
- Macrocyclic hosts are crucial for selective ion binding and constructing complex architectures.
- Metallomacrocycles offer unique electronic and structural properties for host-guest chemistry.
- Tuning macrocycle structure influences ion recognition and self-assembly.
Purpose of the Study:
- To synthesize and characterize a rigid, soluble nickel(II) bis(saloph) macrocyclic host with xanthene motifs.
- To investigate the ion recognition and aggregation behavior of the synthesized host toward alkali metal ions.
- To explore the formation of higher-order supramolecular assemblies based on host-guest interactions.
Main Methods:
- Synthesis of a planar nickel(II) bis(saloph) macrocyclic host (L2bNi2).
- Ion recognition studies using 1H NMR titration and mass spectrometry.
- Structural elucidation via X-ray crystallography.
- Theoretical calculations to support experimental observations.
Main Results:
- The nickel(II) macrocycle formed a 2:1 (host/guest) complex with Na+, shifting to a 1:1 complex upon further addition.
- Larger alkali metal ions (K+, Rb+, Cs+) formed stable 2:1 (host/guest) dimeric complexes.
- These dimeric complexes assembled into higher-order structures (2:2, 2:3, 3:2) depending on the cation.
- X-ray crystallography revealed hexagonal planar coordination for Na+ and orthogonal stacking for larger cations.
- Theoretical calculations confirmed that larger ions favor 2:1 complexation due to reduced repulsion.
Conclusions:
- The aggregation behavior of the metallomacrocycle is highly sensitive to the size and coordination preferences of alkali metal guests.
- The preorganized, metal-based macrocycle enables the construction of dynamic, multivalent supramolecular architectures.
- This work provides insights into cation-modulated self-assembly in metallosupramolecular chemistry.
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