scholarly journals Thermodynamic and electrochemical study of tailor-made crown ethers for redox-switchable (pseudo)rotaxanes

2020 ◽  
Vol 16 ◽  
pp. 2576-2588
Author(s):  
Henrik Hupatz ◽  
Marius Gaedke ◽  
Hendrik V Schröder ◽  
Julia Beerhues ◽  
Arto Valkonen ◽  
...  
Keyword(s):  
Crown Ethers ◽  
Building Blocks ◽  
Binding Energies ◽  
Titration Calorimetry ◽  
Emergent Properties ◽  
Naphthalene Diimide ◽  
Redox Active ◽  
Voltammetric Techniques ◽  
Redox Switching ◽  
Redox Switches

Crown ethers are common building blocks in supramolecular chemistry and are frequently applied as cation sensors or as subunits in synthetic molecular machines. Developing switchable and specifically designed crown ethers enables the implementation of function into molecular assemblies. Seven tailor-made redox-active crown ethers incorporating tetrathiafulvalene (TTF) or naphthalene diimide (NDI) as redox-switchable building blocks are described with regard to their potential to form redox-switchable rotaxanes. A combination of isothermal titration calorimetry and voltammetric techniques reveals correlations between the binding energies and redox-switching properties of the corresponding pseudorotaxanes with secondary ammonium ions. For two different weakly coordinating anions, a surprising relation between the enthalpic and entropic binding contributions of the pseudorotaxanes was discovered. These findings were applied to the synthesis of an NDI-[2]rotaxane, which retains similar spectroelectrochemical properties compared to the corresponding free macrocycle. The detailed understanding of the thermodynamic and electrochemical properties of the tailor-made crown ethers lays the foundation for the construction of new types of molecular redox switches with emergent properties.

scholarly journals Flat Crown Ethers with Planar Tetracoordinate Carbon Atoms

2020 ◽  
Author(s):  
Venkatesan Thimmakondu ◽  
Krishnan Thirumoorthy
Keyword(s):  
Carbon Atom ◽  
Crown Ether ◽  
Crown Ethers ◽  
In Silico ◽  
Alkaline Earth ◽  
Experimental Studies ◽  
Building Blocks ◽  
Binding Energies ◽  
High Symmetry ◽  
Structural Rigidity

Novel flat crown ether molecules have been characterized in silico using DFT hybrid and hybrid-meta functionals. Monomer units of Si2C3 with a planar tetracoordinate carbon atom have been used as building blocks. Alkali (Li+, Na+, K+, Rb+, and Cs+) and alkaline-earth (Ca2+, Sr2+, and Ba2+) metals, and uranyl (UO2+ 2 ) ion selective complexes have also been theoretically identified. The high symmetry and higher structural rigidity of the host molecules may likely to impart higher selectivity in chelation. Theoretical binding energies have been computed and experimental studies are invited.

scholarly journals Organomagnesium Crown Ethers and Their Binding Affinities with Li+, Na+, K+, Be2+, Mg2+, and Ca2+ Ions - a Theoretical Study

2021 ◽  
Author(s):  
Krishnan Thirumoorthy ◽  
Uday Kumar Padidela ◽  
Pothiappan Vairaprakash ◽  
Venkatesan Thimmakondu
Keyword(s):  
Metal Ions ◽  
Crown Ethers ◽  
Density Functional ◽  
Building Blocks ◽  
Binding Energies ◽  
Binding Affinities ◽  
Free Energies ◽  
Delta G ◽  
Cluster Methods ◽  
First Time

Novel organomagnesium crown ether molecules have been computationally characterized for the first time using density functional theory (DFT). Monomer units of MgC6 have been used as building blocks. The potential energy surface of the parent elemental composition, MgC6H2, has been extensively explored using both DFT and coupled-cluster methods. It is concluded that the seven-membered ring isomer, 1-magnesacyclohept-4-en-2,6-diyne, is the thermodynamically most stable molecule at all levels. Thus, the latter has been used as the building block for organomagnesium crown ethers. Both alkali (Li+, Na+, and K+) and alkaline-earth (Be2+, Mg2+, and Ca2+) metal ions selective complexes have been theoretically identified. Binding energies (Delta E at 0 K) and thermally corrected Gibbs free energies (Delta G at 298.15 K) have<br>been computed for these metal ions with MgC6-9-crown-3 and MgC6-12-crown-4 to gauge their binding affinities.Novel organomagnesium crown ether molecules have been computationally characterized for the first time using density functional theory (DFT). Monomer units of MgC6 have been used as building blocks. The potential energy surface of the parent elemental composition, MgC6H2, has been extensively explored using both DFT and coupled-cluster methods. It is concluded that the seven-membered ring isomer, 1-magnesacyclohept-4-en-2,6-diyne, is the thermodynamically most stable molecule at all levels. Thus, the latter has been used as the building block for organomagnesium crown ethers. Both alkali (Li+, Na+, and K+) and alkaline-earth (Be2+, Mg2+, and Ca2+) metal ions selective complexes have been theoretically identified. Binding energies (Delta E at 0 K) and thermally corrected Gibbs free energies (Delta G at 298.15 K) have been computed for these metal ions with MgC6-9-crown-3 and MgC6-12-crown-4 to gauge their binding affinities.

scholarly journals Organomagnesium Crown Ethers and Their Binding Affinities with Li+, Na+, K+, Be2+, Mg2+, and Ca2+ Ions - a Theoretical Study

2021 ◽  
Author(s):  
Krishnan Thirumoorthy ◽  
Uday Kumar Padidela ◽  
Pothiappan Vairaprakash ◽  
Venkatesan Thimmakondu
Keyword(s):  
Metal Ions ◽  
Crown Ethers ◽  
Density Functional ◽  
Building Blocks ◽  
Binding Energies ◽  
Binding Affinities ◽  
Free Energies ◽  
Delta G ◽  
Cluster Methods ◽  
First Time

Novel organomagnesium crown ether molecules have been computationally characterized for the first time using density functional theory (DFT). Monomer units of MgC6 have been used as building blocks. The potential energy surface of the parent elemental composition, MgC6H2, has been extensively explored using both DFT and coupled-cluster methods. It is concluded that the seven-membered ring isomer, 1-magnesacyclohept-4-en-2,6-diyne, is the thermodynamically most stable molecule at all levels. Thus, the latter has been used as the building block for organomagnesium crown ethers. Both alkali (Li+, Na+, and K+) and alkaline-earth (Be2+, Mg2+, and Ca2+) metal ions selective complexes have been theoretically identified. Binding energies (Delta E at 0 K) and thermally corrected Gibbs free energies (Delta G at 298.15 K) have<br>been computed for these metal ions with MgC6-9-crown-3 and MgC6-12-crown-4 to gauge their binding affinities.Novel organomagnesium crown ether molecules have been computationally characterized for the first time using density functional theory (DFT). Monomer units of MgC6 have been used as building blocks. The potential energy surface of the parent elemental composition, MgC6H2, has been extensively explored using both DFT and coupled-cluster methods. It is concluded that the seven-membered ring isomer, 1-magnesacyclohept-4-en-2,6-diyne, is the thermodynamically most stable molecule at all levels. Thus, the latter has been used as the building block for organomagnesium crown ethers. Both alkali (Li+, Na+, and K+) and alkaline-earth (Be2+, Mg2+, and Ca2+) metal ions selective complexes have been theoretically identified. Binding energies (Delta E at 0 K) and thermally corrected Gibbs free energies (Delta G at 298.15 K) have been computed for these metal ions with MgC6-9-crown-3 and MgC6-12-crown-4 to gauge their binding affinities.

scholarly journals Flat Crown Ethers with Planar Tetracoordinate Carbon Atoms

2020 ◽  
Author(s):  
Venkatesan Thimmakondu ◽  
Krishnan Thirumoorthy
Keyword(s):  
Carbon Atom ◽  
Crown Ether ◽  
Crown Ethers ◽  
In Silico ◽  
Alkaline Earth ◽  
Experimental Studies ◽  
Building Blocks ◽  
Binding Energies ◽  
High Symmetry ◽  
Structural Rigidity

Novel flat crown ether molecules have been characterized in silico using DFT hybrid and hybrid-meta functionals. Monomer units of Si2C3 with a planar tetracoordinate carbon atom have been used as building blocks. Alkali (Li+, Na+, K+, Rb+, and Cs+) and alkaline-earth (Ca2+, Sr2+, and Ba2+) metals, and uranyl (UO2+ 2 ) ion selective complexes have also been theoretically identified. The high symmetry and higher structural rigidity of the host molecules may likely to impart higher selectivity in chelation. Theoretical binding energies have been computed and experimental studies are invited.

scholarly journals Core-Substituted Naphthalene-diimides (cNDI) and Related Derivatives: Versatile Scaffold for Supramolecular Assembly and Functional Materials

2021 ◽  
Author(s):  
Anurag Mukherjee ◽  
Suhrit Ghosh
Keyword(s):  
Photophysical Properties ◽  
Supramolecular Assembly ◽  
Functional Materials ◽  
Building Blocks ◽  
Short Review ◽  
Molecular Engineering ◽  
Organic Optoelectronics ◽  
Naphthalene Diimide ◽  
Naphthalene Diimides ◽  
Derivatives Of

Naphthalene-diimide (NDI) derived building blocks have been explored extensively for supramolecular assembly as they exhibit attractive photophysical properties, suitable for applications in organic optoelectronics. Core-substituted derivatives of the NDI chromophore (cNDI) differ significantly from the parent NDI dye in terms of optical and redox properties. Adequate molecular engineering opportunities and substitution-dependent tunable optoelectronic properties make cNDI derivatives highly promising candidates for supramolecular assembly and functional material. This short review discusses recent development in the area of functional supramolecular assemblies based on cNDIs and related molecules.

scholarly journals Nickel Salicylaldoxime-Based Coordination Polymer as a Cathode for Lithium-Ion Batteries

Energies ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2480
Author(s):  
Evgenii V. Beletskii ◽  
Daniil A. Lukyanov ◽  
Petr S. Vlasov ◽  
Andrei N. Yankin ◽  
Arslan B. Atangulov ◽  
...  
Keyword(s):  
Energy Storage ◽  
Cathode Materials ◽  
Lithium Ion ◽  
Building Blocks ◽  
Organic Polymer ◽  
Galvanostatic Charge ◽  
X Ray ◽  
Storage Performance ◽  
Redox Active ◽  
Metal Organic

Conjugated coordination polymers attract attention as materials for electrochemical energy storage, mostly as cathode materials for supercapacitors. Faradaic capacity may be introduced to such materials using redox-active building blocks, metals, or ligands. Using this strategy, a novel hybrid cathode material was developed based on a Ni2+ metal-organic polymer. The proposed material, in addition to double-layer capacitance, shows high pseudocapacitance, which arises from the contributions of both the metal center and ligand. A tailoring strategy in the ligand design allows us to minimize the molecular weight of the ligand, which increases its gravimetric energy. According to computational results, the ligand makes the prevailing contribution to the pseudocapacitance of the material. Different approaches to metal–organic polymer (MOP) synthesis were implemented, and the obtained materials were examined by FTIR, Raman spectroscopy, powder XRD, SEM/EDX (energy-dispersive X-ray spectroscopy), TEM, and thermal analysis. Energy-storage performance was comparatively studied with cyclic voltammetry (CV) and galvanostatic charge–discharge (GCD). As a result, materials with an excellent discharge capacity were obtained, reaching the gravimetric energy density of common inorganic cathode materials.

Crown Ethers as Building Blocks for Carbohydrate Receptors

2006 ◽  
Vol 8 (5) ◽  
pp. 855-858 ◽  
Author(s):  
Monika Mazik ◽  
Matthias Kuschel ◽  
Willi Sicking
Keyword(s):  
Crown Ethers ◽  
Building Blocks

scholarly journals Enhancing photovoltages at p-type semiconductors through a redox-active metal-organic framework surface coating

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Anna M. Beiler ◽  
Brian D. McCarthy ◽  
Ben A. Johnson ◽  
Sascha Ott
Keyword(s):  
Metal Organic Framework ◽  
Three Dimensions ◽  
Photoelectrochemical Performance ◽  
Naphthalene Diimide ◽  
Thermodynamic Potentials ◽  
Redox Active ◽  
Active Metal ◽  
Metal Organic ◽  
Conductive Substrates ◽  
P Type

AbstractSurface modification of semiconductors can improve photoelectrochemical performance by promoting efficient interfacial charge transfer. We show that metal-organic frameworks (MOFs) are viable surface coatings for enhancing cathodic photovoltages. Under 1-sun illumination, no photovoltage is observed for p-type Si(111) functionalized with a naphthalene diimide derivative until the monolayer is expanded in three dimensions in a MOF. The surface-grown MOF thin film at Si promotes reduction of the molecular linkers at formal potentials >300 mV positive of their thermodynamic potentials. The photocurrent is governed by charge diffusion through the film, and the MOF film is sufficiently conductive to power reductive transformations. When grown on GaP(100), the reductions of the MOF linkers are shifted anodically by >700 mV compared to those of the same MOF on conductive substrates. This photovoltage, among the highest reported for GaP in photoelectrochemical applications, illustrates the power of MOF films to enhance photocathodic operation.

scholarly journals Generation of Bis(ferrocenyl)silylenes from Siliranes

Molecules ◽  
2020 ◽  
Vol 25 (24) ◽  
pp. 5917
Author(s):  
Yang Pan ◽  
Shogo Morisako ◽  
Shinobu Aoyagi ◽  
Takahiro Sasamori
Keyword(s):  
Transition Metal ◽  
Building Block ◽  
Building Blocks ◽  
Redox Behavior ◽  
Organosilicon Compounds ◽  
Design And Synthesis ◽  
Mild Conditions ◽  
Redox Active ◽  
Electronic Perturbation ◽  
Active Transition

Divalent silicon species, the so-called silylenes, represent attractive organosilicon building blocks. Isolable stable silylenes remain scarce, and in most hitherto reported examples, the silicon center is stabilized by electron-donating substituents (e.g., heteroatoms such as nitrogen), which results in electronic perturbation. In order to avoid such electronic perturbation, we have been interested in the chemistry of reactive silylenes with carbon-based substituents such as ferrocenyl groups. Due to the presence of a divalent silicon center and the redox-active transition metal iron, ferrocenylsilylenes can be expected to exhibit interesting redox behavior. Herein, we report the design and synthesis of a bis(ferrocenyl)silirane as a precursor for a bis(ferrocenyl)silylene, which could potentially be used as a building block for redox-active organosilicon compounds. It was found that the isolated bis(ferrocenyl)siliranes could be a bottleable precursor for the bis(ferrocenyl)silylene under mild conditions.

scholarly journals Multivalent Lactose–Ferrocene Conjugates Based on Poly (Amido Amine) Dendrimers and Gold Nanoparticles as Electrochemical Probes for Sensing Galectin-3

Nanomaterials ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 203 ◽  
Author(s):  
Manuel C. Martos-Maldonado ◽  
Indalecio Quesada-Soriano ◽  
Luis García-Fuentes ◽  
Antonio Vargas-Berenguel
Keyword(s):  
Gold Nanoparticles ◽  
Surface Modification ◽  
Cardiac Remodeling ◽  
Building Blocks ◽  
Differential Pulse ◽  
Pamam Dendrimers ◽  
Titration Calorimetry ◽  
Vis Spectroscopy ◽  
Galectin 3 ◽  
Pulse Voltammetry

Galectin-3 is considered a cancer biomarker and bioindicator of fibrosis and cardiac remodeling and, therefore, it is desirable to develop convenient methods for its detection. Herein, an approach based on the development of multivalent electrochemical probes with high galectin-3 sensing abilities is reported. The probes consist of multivalent presentations of lactose–ferrocene conjugates scaffolded on poly (amido amine) (PAMAM) dendrimers and gold nanoparticles. Such multivalent lactose–ferrocene conjugates are synthesized by coupling of azidomethyl ferrocene–lactose building blocks on alkyne-functionalized PAMAM, for the case of the glycodendrimers, and to disulfide-functionalized linkers that are then used for the surface modification of citrate-stabilized gold nanoparticles. The binding and sensing abilities toward galectin-3 of both ferrocene-containing lactose dendrimers and gold nanoparticles have been evaluated by means of isothermal titration calorimetry, UV–vis spectroscopy, and differential pulse voltammetry. The highest sensitivity by electrochemical methods to galectin-3 was shown by lactosylferrocenylated gold nanoparticles, which are able to detect the lectin in nanomolar concentrations.

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