Molecular rotors in porous organic frameworks
Angiolina Comotti1, Silvia Bracco, Teng Ben
1Department of Materials Science, University of Milano Bicocca, Via R. Cozzi 53, Milano (Italy) http://www.mater.unimib.it/utenti/sozzani.
Angewandte Chemie (International Ed. in English)
|January 10, 2014
Summary
Researchers discovered ultra-fast molecular rotors in porous organic frameworks, enabling dynamic materials with tunable motion for advanced applications like sensors and actuators.
Area of Science:
- Materials Science
- Nanotechnology
- Physical Chemistry
Background:
- Porous organic frameworks (POFs) possess large surface areas, enabling diverse functions.
- The dynamic behavior of structural elements within POFs remains largely unexplored.
Purpose of the Study:
- To investigate the dynamics of structural elements in porous organic frameworks.
- To explore the potential of fast molecular rotors in POF architectures.
Main Methods:
- Characterization of molecular rotor dynamics within POF structures.
- Temperature-dependent studies of rotational motion.
Main Results:
- Discovery of ultra-fast molecular rotors (10^6 Hz at 225 K) within POF architectures.
- Demonstration of tunable rotational motion, controllable by temperature and guest molecules.
- Observation of rotors approaching free-rotational diffusion at 550 K.
Conclusions:
- POFs can be engineered as dynamic materials with controllable motion via molecular rotors.
- The combination of nanoporosity and fast dynamics opens avenues for responsive materials.
- Potential applications include switchable ferroelectricity, sensors, and actuators for controlled chemical capture and release.
More Related Videos
Related Concept Videos
01:09Radical Chain-Growth Polymerization: Mechanism
2.9K
The radical chain-growth polymerization mechanism consists of three steps: initiation, propagation, and termination of polymerization. The polymerization initiates when a free radical generated from the radical initiator adds to the unsaturated bond in the monomer. The unpaired electron of the free radical and one π electron in the unsaturated bond creates a σ bond between the free radical and the monomer. As a result, the other π electron in the unsaturated bond converts this...
2.9K
01:10Radical Chain-Growth Polymerization: Overview
2.7K
Chain-growth or addition polymerization is successive addition reactions of monomers with a polymer chain. In radical chain-growth polymerization, the reaction proceeds via a free-radical intermediate. The free radical is formed from radical initiators, which spontaneously generate free radicals by homolytic fission. Organic peroxides (such as dibenzoyl peroxide, as shown in Figure 1) or azo compounds are popular radical initiators. A low concentration ratio of radical initiator to monomer is...
2.7K
01:11ortho–para-Directing Activators: –CH3, –OH, –NH2, –OCH3
5.0K
All ortho–para directors, excluding halogens, are activating groups. These groups donate electrons to the ring, making the ring carbons electron-rich. Consequently, the reactivity of the aromatic ring towards electrophilic substitution increases. For instance, the nitration of anisole is about 10,000 times faster than the nitration of benzene. The electron-donating effect of the methoxy group in anisole activates the ortho and para positions on the ring and stabilizes the corresponding...
5.0K
01:17Radical Chain-Growth Polymerization: Chain Branching
1.8K
The skeletal structure of polymers synthesized via radical polymerization is always branched. For example, the polymerization of ethylene by radical polymerization results in a low-density grade of polyethylene with a heavily branched skeletal structure. Here, the radical site abstracts hydrogen from the growing chain, and the radical site shifts from the end (a primary carbon center) to anywhere within the growing chain (a secondary carbon center). Consequently, the part of the chain from the...
1.8K
02:06Newman Projections
16.9K
Different notations are used to represent the three-dimensional structure of molecules on two-dimensional surfaces. One of the most commonly used representations is the dash-wedge formula. The dashed wedges, solid wedges, and the plane lines indicate the groups situated behind the plane, coming out of the plane, and in the plane, respectively.
The organic molecules rotate across the single bonds leading to numerous temporary three-dimensional structures of varying energy known as...
The organic molecules rotate across the single bonds leading to numerous temporary three-dimensional structures of varying energy known as...
16.9K
01:18Aromatic Hydrocarbon Anions: Structural Overview
3.5K
Neutral hydrocarbons like cyclopentadiene with an odd number of carbon atoms and one intervening CH2 group in the ring are not aromatic. Cyclopentadiene with 4 π electrons does not satisfy the 4n + 2 π electron rule. Additionally, the intervening CH2 group is sp3 hybridized and lacks a vacant p orbital, thereby interrupting the overlap of p orbitals in a continuous manner and preventing the delocalization of π electrons throughout the ring.
Due to the absence of continuous...
Due to the absence of continuous...
3.5K