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81.
Dr. Claudia Mondelli Dr. Sandro Zorzi Dr. Giulia Ricci Dr. Victór Galvan Dr. Eleonora Balliana Dr. Ralf Schweins Prof. Elti Cattaruzza 《Chemphyschem》2020,21(10):966-970
Ceramics are complex objects and a rich source of information: they constitute a large part of the staple memory of past and present human activities. A deep understanding of traditional ceramics is an essential key to designing new ceramic materials. The demanding synthesis of ceramics with fine-tuned properties, such as enhanced mechanical, electrical, optical or magnetic characteristics, must be associated with cutting-edge analysis procedures in order to improve the engineering process. In this context, we describe a neutron-based non-destructive approach to investigating the nanoporosity of an historical pottery matrix as an effective investigation technique for exploring both traditional and advanced ceramic materials. 相似文献
82.
The photochemical activity of the leaves and chloroplasts of several species of plants developed in gaseous hydrocarbon environments (CnH2n+2) was investigated by the EPR method. The influence of different concentrations of paramagnetic ions [Mn(II), Cu(II) and VO(II), respectively] on the plants grown in dietary media containing these ions was also followed by EPR spectroscopy. The contents of paramagnetic ions, lower than 0.1%, in the nutritive solutions, are the most suitable in the biosynthesis of chlorophyll-like pigments containing paramagnetic ions in their porphyrine ring. The changes in the form, structure and photosensibility of the EPR signals corresponding to the free radicals, as well as the properties of the pheophytins containing paramagnetic ions, such as: Mn(II), Cu(II) and VO(II), were related to the photochemical synthesis in gaseous hydrocarbon environments. 相似文献
83.
Gabriella Bombieri Eleonora Forsellini Rodolfo Graziani Guiseppe C. Pappalardo 《Transition Metal Chemistry》1979,4(2):70-72
Summary The crystal structure of [DPSH]
3
+
[UO2[NCS)5]3– (DPSH = 2 pyridylthio-2-pyridinium) has been determined by standard methods using diffractometer data. Crystals are monoclinic, space groupP21/a, witha=33.16 (3),b=16.68(2),c=7.85(1) Å, and=97.3(1); Dc=1.65 g · cm–3 for Z=4. The structure has been refined to R=5.8% by least squares methods. Five thiocyanate groups are equatorially bonded to the linear uranyl group. The mean of the five U-N, N-C, and C-S bond distances are 2.45, 1.17, and 1.59 Å respectively. The protonated DPS molecules have the N,N-inside conformations. 相似文献
84.
Summary The kinetics of the acid-catalysed hydrolysis of the [(imidazole)4Co(CO3)]+ ion was found to follow the rate law -dln[complex]/dt = k
1
K[H+](1 + K[H
+]) in the 25–45 °C range, [H+] 0.05–1.0 m range and I = 1.0m. The reaction sequence consists of a rapid protonation equilibrium followed by the one-end dissociation of the coordinated
carbonato ligand (rate-determining step) and subsequent fast release of the monodentate carbonato ligand. The rate parameter
values, k
1 and ITK, at 25 °C are 6.48 × 10−3s−1 and 0.31m
−1, respectively, and activation parameters for k
1 are ΔH
1
≠ = 86.1 ± 1.2kJ mol−1 and ΔS
1
≠ = 2.1 ± 6.3 J mol−1K−1. The hydrolysis rate increases with increase in ionic strength. The different ways of dealing with the data fit are presented
and discussed. The kinetic results are compared with those for the similar cobalt(III) complexes. 相似文献
85.
86.
Dr. Cristina Parisi Dr. Mariacristina Failla Dr. Aurore Fraix Dr. Barbara Rolando Dr. Eleonora Gianquinto Prof. Francesca Spyrakis Dr. Elena Gazzano Prof. Chiara Riganti Prof. Loretta Lazzarato Prof. Roberta Fruttero Prof. Alberto Gasco Prof. Salvatore Sortino 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(47):11080-11084
Two novel NO photodonors (NOPDs) based on BODIPY and Rhodamine antennae activatable with the highly biocompatible green light are reported. Both NOPDs exhibit considerable fluorescence emission and release NO with remarkable quantum efficiencies. The combination of the photoreleasing and emissive performance for both compounds is superior to those exhibited by other NOPDs based on similar light-harvesting centres, making them very intriguing for image-guided phototherapeutic applications. Preliminary biological data prove their easy visualization in cell environment due to the intense green and orange-red fluorescence and their photodynamic action on cancer cells due to the NO photo-liberated. 相似文献
87.
Eleonora Freire Griselda Polla Ricardo Baggio 《Acta Crystallographica. Section C, Structural Chemistry》2013,69(2):186-190
The asymmetric unit of the title salt [systematic name: bis(4‐(2,3‐dichlorophenyl)‐1‐{4‐[(2‐oxo‐1,2,3,4‐tetrahydroquinolin‐7‐yl)oxy]butyl}piperazin‐1‐ium) oxalate–oxalic acid (1/1)], 2C23H28Cl2N3O2+·C2O42−·C2H2O4, consists of one protonated aripiprazole unit (HArip+), half an oxalate dianion and half an oxalic acid molecule, the latter two lying on inversion centres. The conformation of the HArip+ cation differs from that in other reported salts and resembles more the conformation of neutral Arip units in reported polymorphs and solvates. The intermolecular interaction linking HArip+ cations is also similar to those in reported Arip compounds crystallizing in the space group P, with head‐to‐head N—H...O hydrogen bonds generating centrosymmetric dimers, which are further organized into planar ribbons parallel to (01). The oxalate anions and oxalic acid molecules form hydrogen‐bonded chains running along [010], which `pierce' the planar ribbons, interacting with them through a number of stronger N—H...O and weaker C—H...O hydrogen bonds, forming a three‐dimensional network. 相似文献
88.
Zhanneta R. Gulyaeva Igor I. Patsanovsky Eleonora A. Ishmaeva Lech Stefaniak Wojciech Domalewski 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-4)
Abstract A series of iminophosphoranes o-X-C6H4-N=PPh3, where X=H(I),Me (II),Et (III),OMe(IV),OEt(V) were investigated by means of dipole moments method. Because of an orientation of aromatic fragment determines intramolecular interactions in the system (benzene ring - double N=P bond), the problem of internal rotation of N-Car bond is important. DM (exp.) of molecules (I-V), determined in dioxane are 4.30(I), 4.34(II), 4.53(III), 4.75(IV), 4.79 D(V), respectively. 相似文献
89.
Federico Iori Eleonora Luppi Ivan Marri D. Ninno Stefano Ossicini 《Journal of luminescence》2006,121(2):335-339
There are experimental evidences that doping control at the nanoscale can significantly modify the optical properties with respect to the pure systems. This is the case of silicon nanocrystals (Si-nc), for which it has been shown that the photoluminescence (PL) peak can be tuned also below the bulk Si band gap by properly controlling the impurities, for example by boron (B) and phosphorus (P) codoping. In this work, we report on an ab initio study of impurity states in Si-nc. We consider B and P substitutional impurities for Si-nc with a diameter up to 2.2 nm. Formation energies (FEs), electronic, optical and structural properties have been determined as a function of the cluster dimension. For both B-doped and P-doped Si-nc the FE increases on decreasing the dimension, showing that the substitutional doping gets progressively more difficult for the smaller nanocrystals. Moreover, subsurface impurity positions result to be the most stable ones. The codoping reduces the FE strongly favoring this process with respect to the simple n-doping or p-doping. Such an effect can be attributed to charge compensation between the donor and the acceptor atoms. Moreover, smaller structural deformations, with respect to n-doped and p-doped cases, localized only around the impurity sites are observed. The band gap and the optical threshold are largely reduced with respect to the undoped Si-nc showing the possibility of an impurity-based engineering of the Si-nc PL properties. 相似文献
90.
Paola Taddei Eleonora Pavoni Masuhiro Tsukada 《Journal of Raman spectroscopy : JRS》2016,47(6):731-739
Bombyx mori silk fibroin fibers were grafted with methacrylamide (MAA) and characterized by Raman and infrared (IR) vibrational spectroscopy before and after hydrolysis in NaOH 5% to elucidate the possible interactions between the two components and the stability of the fibers toward alkaline hydrolysis. Upon grafting, the fibers underwent conformational rearrangements toward a more unordered state and lost orientation at weight gains higher than 60%. Vibrational spectroscopy disclosed the occurrence of intermolecular interactions (mainly hydrogen bonds) between B. mori silk fibroin and polyMAA in the grafted fibers, and the formation of covalent bonds has been explored. These strong interactions made the grafted fibers as a whole more stable toward alkaline hydrolysis because they prevented the solubilization of the polymer upon hydrolysis and made slower the transformation of its CONH2 groups into COOH and COO− groups. Upon hydrolysis, silk fibroin underwent an enrichment in the β‐sheet crystalline domains, because of the preferential removal of the unordered domains, which were more prone to the OH− attack. IR and Raman spectroscopy proved valid techniques to investigate the degradation mechanism and kinetics of grafted silk fibroin fibers and so for designing high‐performing silk‐based materials. The A731/A1004 Raman intensity ratio was proposed to spectroscopically evaluate the composition of the grafted samples; its value was found to linearly increase with weight gain (R2 = 0.998), envisaging the possibility of using Raman spectroscopy as a routine analytical technique for qualitative and quantitative characterization of grafted industrial samples. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献