Trinuclear to Dinuclear: A Radii Dependence Lanthanide(III) Self-Assembly Coordination Behavior of an Amide-Type Tripodal Ligand

Lanthanide nitrate complexes with the heptadentate ligand L (6-[2-(2-(diethylamino)-2-oxoethoxy)ethyl]-N,N,12-triethyl-11-oxo-3,9-dioxa-6,12-diazatetradecanamide), [Ln2L(NO3)6] (Ln = La, Nd, Sm, Eu, Ho), have been prepared and characterized. The X-ray crystallographic studies show that, in [La2L(NO3)6(H2O)]·H2O (1), two complex cations [LaL(H2O)]3+ are linked by a hexanitrato anion [La(NO3)6]3- and form a trinuclear cation. In [Nd2L(NO3)6(H2O)]·CHCl3·1/2CH3OH·1/2H2O (2), one complex cation [NdL(H2O)]3+ and a hexanitrato complex anion [Nd(NO3)6]3- are linked by a bridging NO3- to form a dinuclear complex. In both complexes, the bridging nitrate is an unusual tetradentate ligand. The metal ions are 12-coordinated in hexanitrato anions and 10-coordinated in complex cations. The chainlike supramolecular structures of La3+ complex are parallel and have no hydrogen bonds in between, while, in the Nd3+ complex, a chiral cavity is formed by hydrogen bonds between two adjacent supramolecular chains. These influences are further investigated by assessing the separation efficiency of L and 1H NMR spectra of its lanthanide nitrate mixtures in solution

Trinuclear to Dinuclear: A Radii Dependence Lanthanide(III) Self-Assembly Coordination Behavior of an Amide-Type Tripodal Ligand

Lanthanide nitrate complexes with the heptadentate ligand L (6-[2-(2-(diethylamino)-2-oxoethoxy)ethyl]-N,N,12-triethyl-11-oxo-3,9-dioxa-6,12-diazatetradecanamide), [Ln2L(NO3)6] (Ln = La, Nd, Sm, Eu, Ho), have been prepared and characterized. The X-ray crystallographic studies show that, in [La2L(NO3)6(H2O)]·H2O (1), two complex cations [LaL(H2O)]3+ are linked by a hexanitrato anion [La(NO3)6]3- and form a trinuclear cation. In [Nd2L(NO3)6(H2O)]·CHCl3·1/2CH3OH·1/2H2O (2), one complex cation [NdL(H2O)]3+ and a hexanitrato complex anion [Nd(NO3)6]3- are linked by a bridging NO3- to form a dinuclear complex. In both complexes, the bridging nitrate is an unusual tetradentate ligand. The metal ions are 12-coordinated in hexanitrato anions and 10-coordinated in complex cations. The chainlike supramolecular structures of La3+ complex are parallel and have no hydrogen bonds in between, while, in the Nd3+ complex, a chiral cavity is formed by hydrogen bonds between two adjacent supramolecular chains. These influences are further investigated by assessing the separation efficiency of L and 1H NMR spectra of its lanthanide nitrate mixtures in solution

Acid–Base Properties of Cis-Vacant Montmorillonite Edge Surfaces: A Combined First-Principles Molecular Dynamics and Surface Complexation Modeling Approach

Montmorillonite layer edge surfaces have pH-dependent properties, which arises from the acid–base reactivity of their surface functional groups. Edge surface acidity (with intrinsic reaction equilibrium constant, pKa) is a chemical property that is affected by crystal structure. While a cis-vacant structure predominates in natural montmorillonites, prior molecular-level studies assume a centrosymmetric trans-vacant configuration, which potentially leads to an incorrect prediction of montmorillonite acid–base surface properties. We computed intrinsic acidity constants of the surface sites of a montmorillonite layer with a cis-vacant structure using the first-principles molecular dynamics-based vertical energy gap method. We evaluated pKa values for both non-substituted and Mg-substituted layers on common edge surfaces (i.e., surfaces perpendicular to [010], [01̅0], [110], and [1̅1̅0] crystallographic directions). The functional groups Si­(OH), Al­(OH2)2/Al­(OH)­(OH2), and SiO­(OH)Al sites on surfaces perpendicular to [010] and [01̅0] and Si­(OH)U, Si­(OH)L, Al­(OH2), and Al­(OH2)2 on surfaces perpendicular to [110] and [1̅1̅0] determine the proton reactivity of non-substituted cis-vacant edge surfaces. Moreover, the structural OH sites on edge surfaces had extremely high pKa values, which do not show reactivity at a common pH. Meanwhile, Mg2+ substitution results in an increase in pKa values at local or adjacent sites, in which the effect is limited by the distance between the sites. A surface complexation model was built with predicted pKa values, which enabled us to predict surface properties as a function of pH and ionic strength. Edge surface charge of both trans- and cis-vacant models has little dependence on Mg2+ substitutions, but the dependence on the crystal plane orientation is strong. In particular, at pH below 7, edge surfaces are positively or negatively charged depending on their orientation. Implications of these findings on contaminant adsorption by smectites are discussed

Fe-Modified Cs–P/γ-Al₂O₃ Catalyst for Synthesis of Methyl Methacrylate from Methyl Propionate and Formaldehyde

To meet the increasing demand for methyl methacrylate, a series of Fe modified Cs–P/γ-Al2O3 catalysts were developed through the impregnation method and tested for the aldol condensation of methyl propionate with formaldehyde in a fixed-bed reactor. Through various characterization studies, the physicochemical properties of the catalysts were systematically studied, especially the relationship between the number of the acid sites and catalytic activity. The number of medium acid sites was increased effectively by the addition of Fe, and the catalytic selectivity was improved consequently. Moreover, the reaction conditions were also optimized, and the life span of the optimized catalyst was evaluated. The Cs–P–0.1Fe/γ-Al2O3 showed excellent reusability during a 260 h lifetime experiment

Supramolecular Vector/Drug Coassemblies of Polyglycerol Dendrons and Rutin Enhance the pH Response

A coassembly strategy for a supramolecular vector/drug was proposed with a biocompatible ternary dodecyl-bi­(third-generation polyglycerol (PG) dendrons) (C12-(G3)2) amphiphile, dodecyl sulfobetaine (SB3-12) surfactant, and poorly water-soluble drug rutin. C12-(G3)2 and rutin will mutually enhance their pH response by protonation and deprotonation of dendritic PG and rutin’s ionization as the pH changes from the acidic gastric lumen to the weakly alkaline intestine. SB3-12 may increase the payload and bring about sustained release for rutin by intermolecular interactions. Self-assembling behaviors of C12-(G3)2, SB3-12, sodium dodecyl sulfate (SDS), and dodecyl tri­methyl­ammonium bromide (DTAB) and their hybrids with rutin were characterized by UV–vis spectroscopy, a fluorescence probe, and 1H NMR. UV–vis and 1H NMR were used to identify the position and orientation of rutin in the vectors. The functions of the vector/drug were confirmed by measuring the solubility and in vitro release of rutin. The ternary coassembling vector/drug easily imparted functions of pH-responsive and sustained release without complex synthetic processes. The nanocaves framed by PG dendrons in the micelles provide pH-responsive compartments for rutin and SB3-12 in the supramolecular vector/drug anchors that accommodate rutin by weak interactions. The finely matched supramolecular vector/drug coassemblies exhibit the pH-responsive function for a potential application in the treatment of inflammatory bowel disease

Promoting Osseointegration of Ti Implants through Micro/Nanoscaled Hierarchical Ti Phosphate/Ti Oxide Hybrid Coating

In this study, micro/nanoscaled hierarchical hybrid coatings containing titanium (Ti) phosphate and Ti oxide have been fabricated with the aim of promoting osseointegration of Ti-based implants. Three representative surface coatings, namely, micro/nanograss Ti (P-G-Ti), micro/nanoclump Ti, (P-C-Ti), and micro/nanorod Ti (P-R-Ti), have been produced. In-depth investigations into the coating surface morphology, topography, chemical composition, and the surface/cell interaction have been carried out using scanning electron microscopy, transmission electron microscope, X-ray photoelectron spectroscopy, X-ray diffraction, contact-angle measurement, and protein adsorption assay. In addition, in vitro performance of the coating (cell proliferation, adhesion, and differentiation) has been evaluated using rat bone marrow stromal cells (BMSCs), and in vivo assessments have been carried out based on a rat tibia implantation model. All the hybrid coating modified implants demonstrated enhanced protein adsorption and BMSC viability, adhesion and differentiation, with P-G-Ti showing the best bioactivity among all samples. Subsequent in vivo osseointegration tests confirmed that P-G-Ti has induced a much stronger interfacial bonding with the host tissue, indicated by the 2-fold increase in the ultimate shear strength and over 6-fold increase in the maximum push-out force compared to unmodified Ti implants. The state-of-the-art coating technology proposed for Ti-based implants in this study holds great potential in advancing medical devices for next-generation healthcare technology

Tunable nonlinear optical bistability based on Dirac semimetal in photonic crystal Fabry-Perot cavity

In this paper, we study the nonlinear optical bistability (OB) in a symmetrical multilayer structure. This structure is constructed by embedding a nonlinear three-dimensional Dirac semimetal (3D DSM) into a solution filled one-dimensional photonic crystal Fabry-Perot cavity. OB stems from the third order nonlinear conductivity of 3D DSM and the local field of resonance mode could enhance the nonlinearity and reduce the thresholds of OB. This structure achieves the tunability of OB due to that the transmittance could be modulated by the Fermi energy. OB threshold and threshold width could be remarkably reduced by increasing the Fermi energy. Besides, it is found that the OB curve depends heavily on the angle of incidence of the incoming light, the structural parameters of the Fabry-Perot cavity, and the position of 3D DSM inside the cavity. After parameter optimization, we obtained OB with a threshold of 106 V/m. We believe this simple structure provides a reference idea for realizing low threshold and tunable all optical switching devices. Keywords: Optical bistability, Dirac semimetal, Fabry-Perot cavity

Advancing Multiple Detection in RT-LAMP with a Specific Probe Assembled from Plural Three-Way-Junction Structures

The timely detection of diseases and the accurate identification of pathogens require the development of efficient and reliable diagnostic methods. In this study, we have developed a novel specific multivariate probe termed MRTFP (multivariate real-time fluorescent probe) by assembling strand exchange three-way-junction (3WJ) structures. The 3WJ structures were incorporated into a four-angle probe (FP) and a hexagonal probe (HP), to target the multivariate genes of Salmonella. The FP and HP enable single-step and multiplexed detection in RT-LAMP (real-time loop-mediated isothermal amplification) with exceptional sensitivity and specificity. Encouragingly, real food samples contaminated with Salmonella (Salmonella enteritidis and Salmonella typhimurium) can be readily identified and distinguished with a minimum detectable concentration (MDC) of 103 CFU/mL without the need for further culture. The introduction of MRTFP allows for simultaneous detection of dual or three targets in a single tube for LAMP, thereby improving detection efficiency. The MRTFP simplifies the design of robust multivariate probes, exhibits excellent stability, and avoids interference from multiple probe units, offering significant potential for the development of specific probes for efficient and accurate disease detection and pathogen identification

Improvement of soft-magnetic properties for Fe-based amorphous alloys with high saturation polarization by stress annealing

Stress annealing is utilized for enhancing the magnetic softness of Fe83–xCoxB10Si3C3P1 (x = 0–16) amorphous alloys with saturation polarization up to 1.75 T. All of the stress-annealed alloys exhibit improved soft-magnetic properties, including low coercivity of 1.8–2.2 A/m, low core loss of 0.09–0.11 W/kg at 1.0 T and 50 Hz, and high permeability of 27,000–33,200 at 5 A/m and 1 kHz. Stress annealing induces longitudinal magnetic anisotropy and facilitates the annihilation of free volume, leading to pinning-free domain wall motion, and thus the enhanced magnetic softness. The induced magnetic anisotropy relates to the constrained elastic elongation introduced by stress annealing. The stress-annealed Fe83–xCoxB10Si3C3P1 (x = 0–16) amorphous alloys exhibit excellent magnetic softness, sheding light on the designing and processing of amorphous soft magnetic alloys with high saturation polarization.</p