Search results for "Note"
showing 10 items of 10709 documents
Synthesis, Structure, Spectroscopic Studies and Magnetic Properties of the Tetrakis(5,7‐dichloro‐8‐quinolinolato)gadolinium(III) Complex
2008
The synthesis and structural characterization of the neutral gadolinium tetrakis-type complex with 5,7-dichloro-8-quinolinolato (H5,7ClQ) ligands, [Gd(5,7ClQ)2(H5,7ClQ)2Cl], is reported. The GdIII ion is epta coordinated to one chloride ion and to four ligands: two N,O-chelated monoanions and two as zwitterionic (+NH and O–) monodentate oxygen donors. Electronic and vibrational spectra provide suitable markers to distinguish the presence of deprotonated and protonated ligands. The magnetic behaviour of this compound was investigated and explained by taking into account that π–π stacking interactions between the (H5,7ClQ) ligands give rise to a ferromagnetic interaction between the gadoliniu…
Benzothiazolethione complexes of coinage metals: from mononuclear complexes to clusters and polymers
2019
Abstract The reactions of 2(3H)-benzothiazolethione (Hbtt) with [AuCl(tetrahydrothiophene)] and CuBr2 were studied, and found to yield a tetranuclear cluster compound [Au(btt)]4 [1] and a polymeric structure [CuBr(btt-btt)]n.nTHF (2). Crystallographic and spectroscopic methods were used for the characterization. In 1, the monoanionic ligand acted as a bidentate bridging N,S-donor giving a molecular cluster structure of an asymmetric coordination isomer. In the formation of 2, the ligand was dimerized by forming a S–S bond after deprotonation, and coordination via nitrogen donors to metal atoms took place leading to a polymeric structure. To clarify the diversity of reactions of Hbtt with co…
Upconversion nanoparticles with a strong acid-resistant capping
2016
Water-dispersible upconversion nanoparticles (β-NaYF:Yb,Er, UCNP) coated with a thin shell of a biocompatible copolymer comprising 2-hydroxyethylmethacrylate (HEMA) and 2-acrylamido-2-methyl-1-propanesulphonsulphonic acid (AMPS), which we will term COP, have been prepared by multidentate grafting. This capping is remarkably resistant to strong acidic conditions as low as pH 2. The additional functionality of the smart UCNP@COP nanosystem has been proved by its association to a well-known photosensitizer (namely, methylene blue, MB). The green-to-red emission ratio of the UC@COP@MB nanohybrid exhibits excellent linear dependence in the 7 to 2 pH range as a consequence of the release of the d…
Remote Modification of Bidentate Phosphane Ligands Controlling the Photonic Properties in Their Complexes: Enhanced Performance of [Cu(RN‐xantphos)(N…
2020
A series of copper(I) complexes of the type [Cu(HN-xantphos)(N^N)][PF6] and [Cu(BnN-xantphos)(N^N)][PF6], in which N^N = bpy, Mebpy and Me2bpy, HN-xantphos = 4,6-bis(diphenylphosphanyl)-10H-phenoxazine and BnN-xantphos = 10-benzyl-4,6-bis(diphenylphosphanyl)-10H-phenoxazine is described. The single crystal structures of [Cu(HN-xantphos)(Mebpy)][PF6] and [Cu(BnN-xantphos)(Me2bpy)][PF6] confirm the presence of N^N and P^P chelating ligands with the copper(I) atoms in distorted coordination environments. Solution electrochemical and photophysical properties of the BnN-xantphos-containing compounds (for which the highest-occupied molecular orbital is located on the phenoxazine moiety) are repor…
Tuning the Structure of Galacturonate Hydrogels: External Gelation by Ca, Zn, or Fe Cationic Cross-Linkers
2019
International audience; We show here how the nature of various divalent cations M2+ (Ca2+, Zn2+, or Fe2+) influences the structure and mechanical properties of ionotropic polygalacturonate (polyGal) hydrogels designed by the diffusion of cations along one direction (external gelation). All hydrogels exhibit strong gradients of polyGal and cation concentrations, which are similar for all studied cations with a constant ratio R = [M2+]/[Gal] equal to 0.25, showing that every M2+ cation interacts with four galacturonate (Gal) units all along the gels. The regions of the hydrogels formed in the early stages of the gelation process are also similar for all cations and are homogeneous, with the s…
Experimental and Computational Study of Unique Tetranuclear µ 3 ‐Chloride and µ‐Phenoxo/Chloro‐Bridged Defective Dicubane Cobalt(II) Clusters
2016
Two tetranuclear CoII clusters [Co4(L)2(µ3-Cl)2Cl2] have been prepared by using multidentate diaminobisphenolate ligands. The solid-state structures of the complexes were determined by single-crystal X-ray diffraction. The cores of the cluster compounds can be defined as a two-vertex-deficient dicubane geometry (pseudo-dicubane). In the central unit, the cobalt(II) cations are linked through phenoxide oxygen (outer bridges) and chloride anions (inner bridges), previously unprecedented in this type of cobalt cluster. The magnetic properties were studied by both experimental and computational methods. By using a combination of techniques, we were able to determine the nature and strength of t…
Effect of different protective agents on enamel erosion: An in vitro investigation
2019
Background The purpose of this in vitrostudy was to compare the effect of different protective agents on enamel erosion by measuring mean percentage weight loss. Material and Methods Extracted teeth were sectioned into uniform slabs and enamel specimens were randomly distributed to different groups. Initial weight of all enamel specimens was registered. The protective agents used in this study were Tooth Mousse, MI Paste Plus, Remin Pro and Remin Pro Forte. A control group was treated just with tap water. All the specimens were immersed in Coca-Cola for a total of 8 min at room temperature, dried and weighed. Enamel dissolution caused by acidic soft drink was analyzed: specimens were weighe…
Treatment and restoration of adult dentoalveolar trauma: A clinical case report
2016
Adult dentoalveolar trauma most often occurs in the context of sports activities and traffic accidents. Coronal fractures are the most common type of lesion, followed by tooth luxation. We present the case of a 25-year-old woman who suffered alveolar bone damage and coronal fractures of the upper incisors, with extrusive luxation of the right central incisor, as the result of a fall. On the first visit, manual reduction of the buccal plate was carried out under local anesthesia, with repositioning of the right central incisor and splinting to the neighboring teeth. Composites were used to restore the coronal fractures. After one month, both upper central incisors and the right lateral incis…
Antibacterial Properties of Nanoparticles in Dental Restorative Materials. A Systematic Review and Meta-Analysis
2020
Background and Objectives: Nanotechnology has become a significant area of research focused mainly on increasing the antibacterial and mechanical properties of dental materials. The aim of the present systematic review and meta-analysis was to examine and quantitatively analyze the current evidence for the addition of different nanoparticles into dental restorative materials, to determine whether their incorporation increases the antibacterial/antimicrobial properties of the materials. Materials and Methods: A literature search was performed in the Pubmed, Scopus, and Embase databases, up to December 2018, following PRISMA (Preferred Reporting Items for Systematic Review and Meta-Analysis) …
Insights into how nucleotide supplements enhance the peroxidase-mimicking DNAzyme activity of the G-quadruplex/hemin system
2012
Since the initial discovery of the catalytic capability of short DNA fragments, this peculiar enzyme-like property (termed DNAzyme) has continued to garner much interest in the scientific community because of the virtually unlimited applications in developing new molecular devices. Alongside the exponential rise in the number of DNAzyme applications in the last past years, the search for convenient ways to improve its overall efficiency has only started to emerge. Credence has been lent to this strategy by the recent demonstration that the quadruplex-based DNAzyme proficiency can be enhanced by ATP supplements. Herein, we have made a further leap along this path, trying first of all to deci…