Adamantane Groups Research Articles

Cucurbit[7]uril as the host of adamantane-modified dyes for fluorescence enhancement in aqueous environments.

Taking advantage of the excellent host-guest complexation ability between an auxochrome (adamantane group) and CB[7], the fluorescence emission performance of dyes in water was effectively improved with the addition of two equivalents of CB[7], which provided an efficient method for increasing fluorescence intensity in aqueous environments. Furthermore, these dyes with the host were successfully used in cell imaging.

Effective exciplex host for solution-processed narrowband blue TADF-OLEDs using a 9-(dibenzo[b,d]thiophen-2-yl)-9H-carbazole analogue with an adamantane substituent

Implementing an exciplex host system in the emitting layer is crucial for achieving highly efficient thermally activated delayed fluorescence (TADF) and phosphorescent organic light-emitting diodes (OLEDs). In this study, we successfully designed and synthesized 3-((3r,5r,7r)-adamantan-1-yl)-9-(dibenzo[b,d]thiophen-2-yl)-9H-carbazole (AdCz-DBT) and 9-(dibenzo[b,d]thiophen-2-yl)-9H-carbazole (Cz-DBT) as p-type hosts for the exciplex host implementation, and 7-(4-(tert-butyl)phenyl)-5,9-dioxa-13b-boranaphtho[3,2,1-de]anthracene (tPDBA) as an n-type host. The AdCz-DBT host incorporates a large and robust adamantane group into Cz-DBT, increasing molecular weight, film-forming properties and thermal stability. Additionally, AdCz-DBT maintains energy levels and photophysical properties similar to those of adamantane-free Cz-DBT. Efficient exciplex emission was observed in the blend film due to well-matched energy levels of the synthesized p- and n-type hosts. The introduction of adamantane into Cz-DBT did not hinder exciplex formation, resulting in a relatively high photoluminescence quantum yield and improved charge balance in the mixed host with tPDBA.Ultimately, the solution-processed blue TADF-OLED with the AdCz-DBT:tPDBA blend host demonstrated a relatively high external quantum efficiency of 8.00% and a long operational lifetime, exhibiting excellent performance compared to devices using the Cz-DBT:tPDBA blend host.

Supramolecular Modulation of Fluid Flow in a Self-Powered Enzyme Micropump.

Regulating macroscopic fluid flow by catalytic harnessing of chemical energy could potentially provide a solution for powerless microfluidic devices. Earlier reports have shown that surface-anchored enzymes can actuate the surrounding fluid in the presence of the respective substrate in a concentration-dependent manner. It is also crucial to have control over the flow speed of a self-powered enzyme micropump in various applications where controlled dosing and mixing are required. However, modulating the flow speed independent of the fuel concentration remains a significant challenge. In a quest to regulate the fluid flow in such a system, a supramolecular approach has been adopted, where reversible regulation of enzyme activity was achieved by a two-faced synthetic receptor bearing sulfonamide and adamantane groups. The bovine carbonic anhydrase (BCA) enzyme containing a single binding site favorable to the sulfonamide group was used as a model enzyme, and the enzyme activity was inhibited in the presence of the two-faced inhibitor. The same effect was reflected when the immobilized enzyme was used as an engine to actuate the fluid flow. The flow velocity was reduced up to 53% in the presence of 100 μM inhibitor. Later, upon addition of a supramolecular "host" CB[7], the inhibitor was sequestered from the enzyme due to the higher binding affinity of CB[7] with the adamantane functionality of the inhibitor. As a result, the flow velocity was restored to ∼72%, thus providing successful supramolecular control over a self-powered enzyme micropump.

Integration of a bulky adamantane unit with 9-phenyl-9H-3,9′-bicarbazole: a novel host design for solution-processed narrowband TADF-OLEDs

A p-type host, CzCzPh-mAd, incorporating a bulky and rigid adamantane group, demonstrates promising performance stability for high-efficiency solution-processed OLEDs.

Low dielectric polymers at high frequency with bulky adamantane groups as the linker

Two monomers with adamantane and thermo-crosslinkable benzocyclobutene (BCB) groups have been successfully synthesized. These two monomers can be cured to form polymers with low dielectric properties at a high frequency of 10 GHz.

Strong thickening performance and mechanism of supramolecular system constructed by β-cyclodextrin polymer included adamantane polymer

Introducing supramolecular interactions into polymer systems to improve their properties has recently become a hot topic. However, the formation of supramolecular polymers through host–guest interactions using two types of polymers is rarely reported. In this paper, a novel supramolecular system (ABMN) is prepared by host–guest inclusion of β-cyclodextrin polymer (PAAB) and adamantane polymer (PAMN). Subsequently, the thickening ability and viscoelasticity of ABMN are investigated. The microstructure of ABMN is studied by dynamic light scattering (DLS), atomic force microscopy (AFM), and field emission scanning electron microscopy (FE-SEM). The results show that at the molar ratio of PAAB: PAMN = 1:1 the optimal inclusion is observed with the binding constant between β-cyclodextrin group and adamantane group of 575.33 L/mol. The thickening ability of ABMN is greatly improved when compared to the original polymers. At 90℃ and 32868 mg/L, the viscosity of the ABMN system at 2000 mg/L can reach 38.5 mPa s. The microstructure results evidence that a larger hydrodynamic radius and denser spatial network structures in the ABMN system are formed through the host–guest inclusion interactions. Therefore, the supramolecular system exhibits strong thickening properties and demonstrates exceptional resistance to both temperature and salt, rendering it an optimal candidate for employment in EOR in high-temperature and high-salinity reservoirs.

Erasable, Rewritable, And Reprogrammable Dual Information Encryption Based on Photoluminescent Supramolecular Host-Guest Recognition And Hydrogel Shape Memory.

Information encryption technologies are very important for security, health, commodity, and communications, etc. Novel information encryption mechanisms and materials are desired to achieve multi-mode and re-programmable encryption. Here, wedemonstrate a supramolecular strategy to achieve multi-modal, erasable, reprogrammable, and reusable information encryption by reversibly modulating fluorescence. A butyl-naphthalimide with flexible ethylenediamine functionalized β-cyclodextrin (N-CD) is utilized as fluorescent responsive ink for printing or patterning information on polymer brushes with dangling adamantane group grafted on responsive hydrogels. The photoluminescent naphthalimide moiety is bonded to β-CD and entrapped in the cavity. Its fluorescence is highly weakened in β-CD cavity and recovers after being expelled from the cavity by a competing guest molecule to emit bright green photoluminescence under UV. Experiments and theoretical calculations suggest π-π stacking and ICT as the primary mechanism for the naphthalimides assembly and fluorescence, which can be quenched through insertion of conjugated molecules and recover by removing the insert. Such reversible quenching and recovering are used to achieve repeated writing, erasing, and re-writing of information. Wefurther combine supramolecular recognition and hydrogel shape memory to achieve reversible dual-encryption. This study provides a novel strategy to develop smart materials with improved information security for broad applications. This article is protected by copyright. All rights reserved.

Semi aromatic colorless polyimide coatings for dual electrochromic and electrofluorochromic displays and its potential for information encryption

Based on the concept of minimizing the charge transfer complex effect, the diamine monomer which contains amide bond bridged adamantane group and triarylamine unit was synthesized. Subsequently, two colorless polyimides with excellent electrochemical stability and high fluorescence quantum yield were prepared by polycondensation of the aforementioned diamine monomer with 1,2,4,5-cyclohexanetetracarboxylic acid dianhydride and 4,4'-hexafluoroisopropylidene)-diphthalic anhydride, respectively. CPIs coatings ranging from colorless to oxidized blue exhibit excellent electrochromic behaviors and optical transmittance of 80 %, which is 60 % after 15,000 s electrochemical cycles. Interlayer electrochromic displays constructed through a simple strategy can display tailored patterns during electrochemical process. The color contrast between neutral state and oxidized state is strong, which can be used for encrypted transmission of information. Furthermore, the CPI synthesized from HPMDA (PI-HPMDA) demonstrated remarkable electrofluorescence performance, with the fluorescence of the film being controlled by applying voltage. The solution of PI-HPMDA exhibited a fluorescence quantum efficiency of 32.5 %, and the fluorescence intensity of PI-HPMDA could be reduced in the presence of Fe3+. he responsiveness of PI-HPMDA to Fe3+ is expected for specific ion probes.

Triarylamine-based polyamide containing adamantane group as Fe3+ probe and electrochromic smart devices

A new triarylamine-based polyamide was synthesized from 1,4-cyclohexanedicarboxylic acid and diamine monomer containing adamantane group (PA-CA), which exhibits high fluorescence quantum up to 46.1% and excellent electrochromic behaviors. The photoluminescence of PA-CA was quenched by coordination and internal filtration effect to realize Fe3+ response. Neutral colorless PA-CA film was converted to the oxidized blue in the electrochemical oxidation process and the maximum transmittance reached 80%, and the transmittance still exceeded 55% after 10,000 s. A Sandwich structure electrochromic device with PA-CA as the active layer was constructed with a simple strategy and different contents were displayed through patterned customization. Electrofluorochromic performance was regulated and decoding information was customized by applying voltage changes of the light and dark for PA-CA film. The applications of multifunctional integrated PA-CA responding to stimulus have broad prospects in the field of Fe3+ fluorescence sensors, photodetectors and multicolor electrochromic display devices.

Composite hydrogels with host–guest interaction using cellulose nanocrystal as supramolecular filler

The functional nanocomposite hydrogels are of great interest in the research field of materials science because of their improved mechanical performances and their ability to be used in a wider range of applications. Herein, the supramolecular composite hydrogels were developed and studied using a cellulose nanocrystal (CNC) as bio-based filler. The hydrogels were designed by introducing supramolecular bonding between host β-cyclodextrin (β-CD) and guest adamantane (Ad) groups at the interface between the highly dispersed CNC and the polymer matrix. For this purpose, the CNC surface was successfully modified with Ad to act not only as a reinforcing filler in the polymer network but also as a supramolecular cross-linker with the β-CD-modified polymer. Importantly, CNC exhibited the ability of preserving their good dispersibility in aqueous media, even after modification with the hydrophobic Ad group, owing to electrostatic repulsion among negative charges incorporated onto CNC surface. Furthermore, the modification of CNC with Ad contributed to the greater interfacial compatibility between the filler and the matrix. The present study therefore highlights that the toughness of a hydrogel can be improved by the incorporation of supramolecular bonding as reversible bonding at the filler/matrix interface, which sacrificially depletes the mechanical energy upon deformation of the gels.

Fabrication of thermo and pH-dual sensitive hydrogels with optimized physiochemical properties via host-guest interactions and acylhydrazone dynamic bonding

Stimuli-responsive polymeric hydrogels based on host-guest interactions have demonstrated potential as smart drug delivery platforms. However, host-guest interactions alone have been repeatedly highlighted to provide insufficient mechanical strength for the formed hydrogels likely due to the generally low grafting degrees of functional groups and steric hindrance of polymer backbone and grafted functions. Herein, a combination strategy of reversible addition-fragmentation chain-transfer polymerization (RAFT) and dual crosslinking was employed to fabricate thermo- and pH-dual responsive hydrogels with enhanced mechanical properties. Specifically, two kinds of poly (N-isopropyl acrylamide) (PNIPAM)-based well-defined thermo-sensitive polymers, denoted as PH and PG, consisting of β-cyclodextrin (β-CD) and adamantane (Ad) groups were synthesized via RAFT copolymerization. A facile mixing of PH and PG with commercially available adipic dihydrazide led to the construction of hydrogels via host-guest interactions and dynamic acylhydrazone bonding. The resulting hydrogels not only exhibited pH-switchable sol-gel transitions and temperature-dependent swelling behaviors, but also possessed good stretchability (fracture stress up to 39.97 kPa) and self-healing property (self-healing efficiency above 90%). Notably, the resulting hydrogels showed pH-responsive controlled spatiotemporal release administration of rhodamine B due to the presence of dynamic acylhydrazone links. Together with good cytocompatibility, the hydrogels developed herein represent promising candidates for potential transdermal drug delivery.

One-dimensional architectures built from adamantane-bearing macrocycles with multiple propargyl groups

Two macrocycles having adamantane, aromatic units, and propargyl groups (1, 2) were synthesized and their molecular alignments were investigated for the purpose of creating tubular and pseudopolyrotaxane structures. Macrocycles 1 and 2 have distinct molecular sizes and shapes and possess eight and four substituents, respectively. Each macrocycle afforded two inclusion crystals from two solvent systems. The two crystals of 1 had different macrocyclic backbones and orientation of propargyl groups, and columnar or tubular structures were constructed from 1. In the two crystals of 2, the macrocyclic skeleton and the propargyl groups adopted different geometries. In one crystal of 2, two of the substituents were mutually included within the cavity of the adjacent macrocycles to afford one-dimensional polymers with pseudorotaxane-like structures. In the other crystal of 2, the macrocycles were aligned to form columnar structures. Propargyl groups interacted with other units through mainly CH···π interactions.

Extremely Small Iron Oxide Nanoparticles with pH-Dependent Solubility Transition as T1/T2 Switchable Contrast Agents for MRI

Extremely small iron oxide nanoparticles (ESIONPs), which have a switchable contrast signal and a favorable biocompatibility, are gaining considerable attention as smart magnetic resonance imaging (MRI) contrast agents (CAs). Adaptive MRI CAs could improve the accuracy of tumor diagnosis because they realize rapid imaging signal conversion under an endogenous stimulus. Herein, based on the hydrophilic to hydrophobic transition of polymers, we propose a pH-responsive T1/T2 switchable ESIONP contrast agent. ESIONPs are functionalized at the surface with adamantane groups through a polyethylene glycol (PEG) chain, and subsequently, a stimuli-responsive polymer (PSDM) with pH-dependent solubility is introduced through the host–guest interaction between adamantane and β-cyclodextrin (β-CD). The obtained ESIONPs-PEG-PSDM is equipped with remarkable pH responsiveness, which triggers the aggregation of ESIONPs under the tumor acid condition, leading to the switch from a T1 to a T2 contrast agent. In vivo MRI experiments show that the T2 contrast signal is selectively enhanced at the tumor location after injection of ESIONPs-PEG-PSDM. Therefore, ESIONPs-PEG-PSDM with pH-induced hydrophilic to hydrophobic transition is a potential smart MRI contrast agent for precise tumor diagnosis.

Anti-Inflammatory Activity of Soluble Epoxide Hydrolase Inhibitors Based on Selenoureas Bearing an Adamantane Moiety.

The inhibitory potency of the series of inhibitors of the soluble epoxide hydrolase (sEH) based on the selenourea moiety and containing adamantane and aromatic lipophilic groups ranges from 34.3 nM to 1.2 μM. The most active compound 5d possesses aliphatic spacers between the selenourea group and lipophilic fragments. Synthesized compounds were tested against the LPS-induced activation of primary murine macrophages. The most prominent anti-inflammatory activity, defined as a suppression of nitric oxide synthesis by LPS-stimulated macrophages, was demonstrated for compounds 4a and 5b. The cytotoxicity of the obtained substances was studied using human neuroblastoma and fibroblast cell cultures. Using these cell assays, the cytotoxic concentration for 4a was 4.7–18.4 times higher than the effective anti-inflammatory concentration. The genotoxicity and the ability to induce oxidative stress was studied using bacterial lux-biosensors. Substance 4a does not exhibit genotoxic properties, but it can cause oxidative stress at concentrations above 50 µM. Put together, the data showed the efficacy and safety of compound 4a.

Viscoelastic Metal-in-Water Emulsion Gel via Host-Guest Bridging for Printed and Strain-Activated Stretchable Electrodes.

Stretchable conductive electrodes that can be made by printing technology with high resolution is desired for preparing wearable electronics. Printable inks composed of liquid metals are ideal candidates for these applications, but their practical applications are limited by their low stability, poor printability, and low conductivity. Here, thixotropic metal-in-water (M/W) emulsion gels (MWEGs) were designed and developed by stabilizing and bridging liquid metal droplets (LMDs) via a host–guest polymer. In the MWEGs, the hydrophilic main chain of the host–guest polymers emulsified and stabilized LMDs via coordination bonds. The grafted cyclodextrin and adamantane groups formed dynamic inclusion complexes to bridge two neighboring LMDs, leading to the formation of a dynamically cross-linked network of LMDs in the aqueous phase. The MWEGs exhibited viscoelastic and shear-thinning behavior, making them ideal for direct three-dimensional (3D) and screen printing with a high resolution (∼65 μm) to assemble complex patterns consisting of ∼95 wt % liquid metal. When stretching the printed patterns, strong host–guest interactions guaranteed that the entire droplet network was cross-linked, while the brittle oxide shell of the droplets ruptured, releasing the liquid metal core and allowing it to fuse into continuous conductive pathways under an ultralow critical strain (<1.5%). This strain-activated conductivity exceeded 15800 S/cm under a large strain of 800% and exhibited long-term cyclic stability and robustness.

Adamantane-based block poly(arylene ether sulfone)s as anion exchange membranes

Current anion exchange membranes (AEMs) for fuel cells suffer from low ionic conductivity and poor mechanical property. Herein, we introduce adamantane groups onto the block poly(arylene ether sulfone)s backbone to form the selected comb-shaped structure. The structure-property relationships of the AEMs are investigated by varying the ratio of the hydrophobic to hydrophilic segments. The bulk rigid adamantane group can restrain the swelling of the AEMs thus enhancing the mechanical properties and expand the spacing between the hydrophilic/hydrophobic segments of the polymer chains to promote the formation of microphase separation morphology. Consequently, as characterized by atomic force microscope (AFM) and transmission electron microscopy (TEM), the resulting membranes show well-defined microphase separation between the hydrophilic/hydrophobic segments, resulting in high ionic conductivity range from 27.4 to 90.2 mS cm −1 over a temperature range of 30–80 °C. At the same time, the membranes present ultralow swelling ratio with the levels from 1.6% to 6.1% at 30 °C and from 6.8% to 12.7% at 80 °C, respectively, and thus excellent mechanical properties with the tensile strength as high as 11.52 MPa and elongation at break of 29.28%. The excellent comprehensive properties grant the prepared AEMs bright future for fuel cells. • A series of adamantane-based block poly(arylene ether sulfone)s AEMs was prepared. • Influence of hydrophobic chain segments on AEMs' properties and morphology was studied. • The AEMs showed well-defined microphase separation between the hydrophilic/hydrophobic segments. • The AEMs showed high hydroxide conductivity in the range of 27.4–90.2 mS cm −1 .

High performance positively charged membranes with selective swelling-induced ion transport channels for vanadium flow battery application

The selective swelling technique is adopted for the first time to construct positively charged membranes with selective swelling-induced ion transport channels for vanadium redox flow battery (VRFB). These membranes are prepared based on pyridine and adamantane groups containing poly(aryl ether ketone ketone) (PyAPEKK) polymer. Polymer chains with pyridine groups are selective swelled to form ion transport channels in the polymer membrane using the base-acid interaction between the pyridine groups and mineral acids (H3PO4 and H2SO4). The bulky, rigid, hydrophobic adamantane groups in the polymer increase the rigidity and hydrophobicity of the polymer backbone that reduce the swelling of the membrane and enhance the membrane selectivity. Consequently, a VRFB utilizing this PyAPEKK membrane exhibit impressive battery performance (CE = 98.9%, EE = 92.3% at 80 mA cm−2; CE = 99.3%, EE = 80.56% at 240 mAcm−2). The PyAPEKK membranes exhibited stable VRFB performance for more than 1500 cycles and exhibited excellent chemical stability in ex-situ stability tests. This work demonstrated a convenient, facile, and environmental-friendly way to fabricate advanced positively charged membranes for VRFB.

On the experimental and theoretical calculations of rotameric conformations of a new Schiff base derived from amantadine

Herein, the condensation of amantadine with the aldehyde piperonal resulted in a new Schiff base (1). This molecule was fully characterized by elementary analysis, infrared (IR), ultraviolet-visible (UV-Vis), 13C, 1H nuclear magnetic resonance (NMR) and high-resolution mass spectroscopy, logP (logarithm of partition coefficient), as well as single-crystal X-ray diffraction (SCXRD). The crystal structure crystallizes in the triclinic P1¯ space group with only one molecule of the Schiff base in the asymmetric unit, presenting the adamantane ring disordered over two positions. The crystal self-assembly is stabilized by weak interactions, such as analyzed by Hirshfeld surface. Using the DFT calculation, an energy barrier of 9.075 kcal.mol−1 was found between the two complementary conformations observed experimentally to the adamantane group. The computed infrared spectra (in vacuum and solution) are in good agreement with the experimental data. The energy of the HOMO orbitals was also calculated, in which energy values ​​range -7.4030–7.6027 eV, while LUMO orbitals are in the range of -0.3610–0.5717 eV, in which the polar solvents promoted greater stabilization in the border orbitals. The chemical potential (μ) from 3.467 to 3.520 eV indicate that the structure is stable. The magnitude of the chemical hardness (η) [6.934–7.041 eV] suggests the resistance to deformation of the electronic cloud over small electrostatic disturbances, showing that the system is not very polarizable. This result can be useful to further studies to investigate the coordination ability of compound 1 with hard metal ions.

Феномен эксайтотоксичности как объект фармакологического воздействия при деменциях

Статья посвящена вопросам терапии деменции. Подробно рассматривается место в лечении данной патологии препарата группы адамантанов мемантина — неконкурентного низкоаффинного антагониста NMDA-рецепторов. Подчеркивается, что мемантин занимает совершенно особое место не только в фармакотерапии деменций, но и в нейрофармакологии в целом, представляя собой уникальный регулятор всей системы глутаматергической медиации, своего рода «адаптоген» в отношении глутаматзависимых процессов в центральной нервной системе и «корректор» реакций эксайтотоксичности. Результаты исследований применения мемантина показывают его эффективность при различных формах и при всех стадиях деменции, комплексность воздействия на все основные клинические синдромы (когнитивный, поведенческий, психоэмоциональный), долгосрочность клинических эффектов, сочетаемость с другими лекарственными средствами в рамках комбинированной терапии, хорошую переносимость и безопасность.

Organic β-cyclodextrin Nanoparticle: An Efficient Building Block Between Functionalized Poly(pyrrole) Electrodes and Enzymes.

Glyconanoparticles (GNPs) made by self-assembly of carbohydrate-based polystyrene-block-β-cyclodextrin copolymer are used as a building block for the design of nanostructured biomaterials of electrode. The firm immobilization of GNPs is carried out on electrochemically generated polymer, poly(pyrrole-adamantane), and copolymer, poly(pyrrole-adamantane)/poly(pyrrole-lactobionamide) via host-guest interactions between adamantane and β-cyclodextrin. The ability of GNPs for the specific anchoring of biological macromolecules is investigated using glucose oxidase enzyme modified by adamantane groups as a protein model (GOx-Ad). The immobilization of GOx-Ad is carried out by incubation of an aqueous enzyme solution on a coating of GNPs adsorbed on a platinum electrode. The presence of immobilized GOx-Ad is evaluated in aqueous glucose solution by potentiostating the underlying platinum electrode at 0.7V/SCE for the electro-oxidation of H2 O2 generated by the enzyme. The analytical performance of the bioelectrodes for the detection of glucose is compared to control electrodes prepared without GNPs or without electropolymerized films. The better permeability of copolymer compared to polymer and the possibility to elaborate two alternating layers of GNPs and GOx-Ad are clearly observed. The best amperometric response is recorded with a multilayered bioelectrode displaying a wide linear range linear range of the calibration curve: 68µmol L-1 to 0.1 molL-1 .