Related Experiment Video
Updated: Jul 15, 2026
10:01
Thermal Scanning Conductometry (TSC) as a General Method for Studying and Controlling the Phase Behavior of Conductive Physical Gels
Published on: January 23, 2018
Spin-crossover physical gels: a quick thermoreversible response assisted by dynamic self-organization
Tsuyohiko Fujigaya1, Dong-Lin Jiang, Takuzo Aida
1Department of Chemistry and Biotechnology, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
Chemistry, an Asian Journal
|April 19, 2007
Summary
Iron(II) coordination polymers form thermoreversible physical gels in hydrocarbon solvents, exhibiting spin crossover. Hydrogen bonding and lipophilic interactions are key to their tunable spin transition and rapid thermal response.
Area of Science:
- Materials Science
- Coordination Chemistry
- Supramolecular Chemistry
Background:
- Iron(II) coordination polymers can exhibit spin crossover (SCO) properties.
- Physical gels can be formed from self-assembling coordination polymers.
- Sol-gel transitions can influence material properties.
Purpose of the Study:
- To synthesize and characterize iron(II) triazolate coordination polymers with lipophilic sulfonate counterions.
- To investigate the formation of physical gels and their thermoreversible spin transition behavior.
- To understand the role of hydrogen bonding and lipophilic interactions in the spin crossover event.
Main Methods:
- Synthesis of iron(II) triazolate coordination polymers with varying alkyl chain lengths.
- Solvent-based gelation studies in hydrocarbon solvents.
- Investigation of thermoreversible spin transitions correlated with sol-gel phase transitions.
- Analysis of hydrogen-bonding networks and lipophilic interactions using additives like 1-octanol.
Main Results:
- Successful synthesis of iron(II) coordination polymers forming physical gels in hydrocarbon solvents.
- Observation of thermoreversible spin crossover phenomena linked to the sol-gel transition.
- Identification of a crucial hydrogen-bonding network involving triazolate and sulfonate groups, bridged by water.
- Demonstration that 1-octanol addition is essential for the low-spin state and tunes the spin-transition temperature.
- Enhanced thermal response in gels compared to non-gelling references due to rapid hydrogen-bond network restoration.
Conclusions:
- Iron(II) triazolate coordination polymers with lipophilic sulfonate counterions can form spin-crossover physical gels.
- The spin transition is strongly influenced by hydrogen bonding and lipophilic interactions, which can be modulated by solvent and additives.
- These materials exhibit tunable and rapid thermal responses, making them promising for responsive materials applications.
Related Concept Videos
02:39Phase Transitions: Melting and Freezing
Heating a crystalline solid increases the average energy of its atoms, molecules, or ions, and the solid gets hotter. At some point, the added energy becomes large enough to partially overcome the forces holding the molecules or ions of the solid in their fixed positions, and the solid begins the process of transitioning to the liquid state or melting. At this point, the temperature of the solid stops rising, despite the continual input of heat, and it remains constant until all of the solid is...
01:58Cooperative Allosteric Transitions
Cooperative allosteric transitions can occur in multimeric proteins, where each subunit of the protein has its own ligand-binding site. When a ligand binds to any of these subunits, it triggers a conformational change that affects the binding sites in the other subunits; this can change the affinity of the other sites for their respective ligands. The ability of the protein to change the shape of its binding site is attributed to the presence of a mix of flexible and stable segments in the...
01:58Cooperative Allosteric Transitions
Cooperative allosteric transitions can occur in multimeric proteins, where each subunit of the protein has its own ligand-binding site. When a ligand binds to any of these subunits, it triggers a conformational change that affects the binding sites in the other subunits; this can change the affinity of the other sites for their respective ligands. The ability of the protein to change the shape of its binding site is attributed to the presence of a mix of flexible and stable segments in the...
01:58Cooperative Allosteric Transitions
Cooperative allosteric transitions can occur in multimeric proteins, where each subunit of the protein has its own ligand-binding site. When a ligand binds to any of these subunits, it triggers a conformational change that affects the binding sites in the other subunits; this can change the affinity of the other sites for their respective ligands. The ability of the protein to change the shape of its binding site is attributed to the presence of a mix of flexible and stable segments in the...
01:22Diversity in Cell Signaling Responses
The physiological function of a cell and cellular communication are outcomes of a range of extrinsic signals, intracellular signaling pathways, and cellular responses. No two cell types express the same repertoire of signaling components. Receptors are highly selective for their cognate ligands, but once activated, they can alter multiple cellular processes such as DNA transcription, protein synthesis, and metabolic activity.
Graded and Abrupt Responses
Some signaling systems generate...
Graded and Abrupt Responses
Some signaling systems generate...
01:23Membrane Fluidity
Cell membranes are composed of phospholipids, proteins, and carbohydrates loosely attached to one another through chemical interactions. Molecules are generally able to move about in the plane of the membrane, giving the membrane its flexible nature called fluidity. Two other features of the membrane contribute to membrane fluidity: the chemical structure of the phospholipids and the presence of cholesterol in the membrane.Fatty acids tails of phospholipids can be either saturated or...