Related Experiment Video
Updated: Mar 20, 2026
10:52
Line Shape Analysis of Dynamic NMR Spectra for Characterizing Coordination Sphere Rearrangements at a Chiral Rhenium Polyhydride Complex
Published on: July 27, 2022
3.4K
Desymmetrization of an Octahedral Coordination Complex Inside a Self-Assembled Exoskeleton
Mark D Johnstone1,2,3, Eike K Schwarze2, Jennifer Ahrens4
1Research Centre for Chemistry and Biotechnology, School of Life and Environmental Sciences, Deakin University, Geelong, Victoria, 3217, Australia.
Chemistry (Weinheim an Der Bergstrasse, Germany)
|June 2, 2016
Summary
A novel coordination cage self-assembles from a polynorbornane ligand and palladium(II) ions. This cage strongly binds octahedral guests like platinum hexacyanide, demonstrating size and charge selectivity for host-guest chemistry.
Area of Science:
- Supramolecular Chemistry
- Coordination Chemistry
- Materials Science
Background:
- Development of self-assembled coordination cages for host-guest chemistry.
- Need for precisely defined supramolecular environments to interact with specific guest molecules.
Purpose of the Study:
- To synthesize a novel coordination cage using a functionalized polynorbornane ligand and Pd(II) ions.
- To investigate the host-guest properties of the resulting cage, particularly its binding affinity and selectivity for various anions and neutral complexes.
Main Methods:
- Self-assembly of a [6]polynorbornane ligand (L) with Pd(II) cations to form a {Pd2 L4 } coordination cage.
- Spectroscopic characterization (NMR, MS, X-ray, IR) of the cage and host-guest complexes.
- Evaluation of binding affinities for different guest molecules based on size and charge.
Main Results:
- Successful synthesis of a shape-persistent {Pd2 L4 } coordination cage with axial cationic centers and equatorial H-bond donors.
- Strong binding observed for octahedral anions [Pt(CN)6 ](2-) and [Fe(CN)6 ](3-), and square-planar [Pt(CN)4 ](2-).
- Evidence of guest desymmetrization within the cage, indicating precise geometric imprinting by the host.
Conclusions:
- The {Pd2 L4 } coordination cage exhibits high affinity and selectivity for specific guest anions, driven by size and charge complementarity.
- The cage's defined supramolecular environment effectively interacts with and influences the geometry of encapsulated guests.
- This work highlights the potential of self-assembled cages in molecular recognition and host-guest chemistry.
Keywords:
anion recognitioncoordination cagesendohedral functionalizationhost-guest chemistrysupramolecular chemistryMore Related Videos
Related Concept Videos
02:46Crystal Field Theory - Tetrahedral and Square Planar Complexes
49.5K
Tetrahedral Complexes
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...
49.5K
02:57Coordination Number and Geometry
19.5K
For transition metal complexes, the coordination number determines the geometry around the central metal ion. Table 1 compares coordination numbers to molecular geometry. The most common structures of the complexes in coordination compounds are octahedral, tetrahedral, and square planar.
19.5K
02:42Valence Bond Theory
11.6K
Coordination compounds and complexes exhibit different colors, geometries, and magnetic behavior, depending on the metal atom/ion and ligands from which they are composed. In an attempt to explain the bonding and structure of coordination complexes, Linus Pauling proposed the valence bond theory, or VBT, using the concepts of hybridization and the overlapping of the atomic orbitals. According to VBT, the central metal atom or ion (Lewis acid) hybridizes to provide empty orbitals of suitable...
11.6K
02:58Crystal Field Theory - Octahedral Complexes
31.6K
Crystal Field Theory
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
31.6K
02:34Structural Isomerism
22.4K
Isomerism in Complexes
Isomers are different chemical species that have the same chemical formula. Structural isomerism of coordination compounds can be divided into two subcategories, the linkage isomers and coordination-sphere isomers.
Linkage isomers occur when the coordination compound contains a ligand that can bind to the transition metal center through two different atoms. For example, the CN− ligand can bind through the carbon atom or through the nitrogen atom. Similarly, SCN− can...
Isomers are different chemical species that have the same chemical formula. Structural isomerism of coordination compounds can be divided into two subcategories, the linkage isomers and coordination-sphere isomers.
Linkage isomers occur when the coordination compound contains a ligand that can bind to the transition metal center through two different atoms. For example, the CN− ligand can bind through the carbon atom or through the nitrogen atom. Similarly, SCN− can...
22.4K
02:52Stereoisomerism
14.4K
Isomerism in Complexes
Isomers are different chemical species that have the same chemical formula.
Transition metal complexes often exist as geometric isomers, in which the same atoms are connected through the same types of bonds but with differences in their orientation in space. Coordination complexes with two different ligands in the cis and trans positions from a ligand of interest form isomers. For example, the octahedral [Co(NH3)4Cl2]+ ion has two isomers (Figure 1) In the cis...
Isomers are different chemical species that have the same chemical formula.
Transition metal complexes often exist as geometric isomers, in which the same atoms are connected through the same types of bonds but with differences in their orientation in space. Coordination complexes with two different ligands in the cis and trans positions from a ligand of interest form isomers. For example, the octahedral [Co(NH3)4Cl2]+ ion has two isomers (Figure 1) In the cis...
14.4K