The thermosalient effect is still a rare and poorly understood phenomenon, where crystals suddenly jump, bend, twist or explode upon undergoing a thermally activated phase transition. The synthesis ...and characterisation of the new spin transition Fe(iii) compound Fe(5-Br-salEen)
ClO
(salEen =
-ethyl-
-(2-aminoethyl)salicylaldiminate) is described and its thermosalient behaviour reported. It is the first example of a thermosalient effect with a spin transition and magnetic, calorimetric, diffraction, microscopy and computational studies are used to characterise these effects. Both thermosalient effect and spin transition occur around 320 K upon heating and are accompanied by an anisotropic unit cell change with conservation of crystal symmetry that causes a large enough stress of the crystal lattice to induce crystal explosion. This stress can ultimately be traced back to a diffusionless and distortive structural perturbation resulting in a coupled spin transition-thermosalient effect.
The new iron(III) complex Fe(5‐I‐salEen)2ClO4 exhibits both spin crossover, with hysteresis, between 304 K and 320 K (16 K hysteresis loop), and thermosalient phenomena. After a symmetry‐breaking ...phase transition between 120 and 130 K, confirmed by single‐crystal X‐ray diffraction, and the fragmentation of the crystals around 312 K, confirmed by differential scanning calorimetry and hot stage microscopy, the hysteresis loop disappears. This is the first example where the explicitly reported thermosalient effect modifies the magnetic properties of a given spin crossover crystal.
Gotta Crack 'em All!: A new spin crossover compound exhibiting thermosalient effects is reported, in a rare event associating both phenomena. Single‐crystal X‐ray measurements and calorimetric studies show non‐related symmetry‐breaking phase transition at low temperatures. The magnetic properties of the crystals are also promising for high‐density memory storage applications.
This dataset is related to the research article entitled “May iron(III) complexes containing phenanthroline derivatives as ligands be prospective anticancer agents?” 1. It includes the ...characterization by UV–Vis absorption spectroscopy and magnetic techniques of a group of mixed ligand Fe(III) complexes bearing a tripodal aminophenolate ligand L2−, H2L = N,N-bis(2-hydroxy-3,5-dimethylbenzyl)-N-(2-pyridylmethyl)amine, and different aromatic bases (NN = 2,2′-bipyridine Fe(L)(bipy)PF6 (1), 1,10-phenanthroline Fe(L)(phen)PF6 (2), or a phenanthroline derivative co-ligand: Fe(L)(amphen)NO3 (3), Fe(L)(amphen)PF6 (3a), Fe(L)(Clphen)PF6 (4), Fe(L)(epoxyphen)PF6 (5) (where amphen = 1,10-phenanthroline-5-amine, epoxyphen = 5,6-epoxy-5,6-dihydro-1,10-phenanthroline, Clphen = 5-chloro-1,10-phenanthroline), as well as Fe(L)(EtOH)NO3 (6), Fe(phen)Cl3 (7) and Fe(amphen)Cl3 (8). Data on their hydrolytic stability in physiological buffers is shown, as well as on their interaction with calf thymus DNA by spectroscopic tools. Additionally, the anticancer efficacy and the cellular death mechanisms activated in response to these drugs in HeLa, H1299 and MDA-MB-231 cells are provided.
An amphiphilic iron(iii) complex with a tridentate Schiff-base ligand was prepared by condensation of a hexadecyloxy functionalised salycylaldehyde with a diamine followed by complexation with FeCl2 ...and anion methathesis with NaClO4. The complex shows spin crossover both in the solid state and solution. However in solution self-assembly and consequently aggregation of individual molecules form concentration dependent particles with sizes of 300 nm for higher concentrations, or 5 nm for lower concentrations. Aggregate formation was confirmed by NANO-flex 180° DLS Size, scan-rate dependent cyclic voltammetry and scanning electron microscopy. Molecular simulations were used to investigate the self-assembly of the complex in solution, including the role of residual water molecules. The simulations showed the self-assembly of reverse micelle-like structures when a small water cluster is inserted in solution, whereas no large aggregates formed in dehydrated environments. The perchlorate anions were found near the metal centres, stabilizing the aggregates around the water pool. Simulations of pre-assembled structures further showed the lack of stability of large aggregates in the absence of water. The larger aggregates promoted efficient communication between the iron(iii) centres and the compound displayed spin crossover in solution at around 220 K with a 10 K hysteresis window, as measured by NMR and SQUID magnetometry.
A pesquisa científica apresentada tem a finalidade de tratar um tema relevante e já estudado em formato de pesquisa científica, que é a gestão por competências na Polícia Militar do Paraná. Na ...metodologia utilizou-se o enfoque qualitativo e como tipo de estudo o descritivo, sendo elaborada uma pesquisa bibliográfica, tendo sido elaborada com base em material já publicado. O artigo tem como objetivo geral apresentar alternativas no aproveitamento adequado das competências dos integrantes da PMPR. Entre os objetivos específicos, estão: compreender os conceitos de competências e demais conceitos relacionados; demonstrar, através de uma análise do Plano estratégico da Polícia Militar de Minas Gerais, como a Gestão por competências foi pensada naquele Estado; propor opções para o aproveitamento adequado das competências na PMPR. Como resultado tem-se que a adoção de uma política adequada de gestão por competências encontra-se em processo de evolução na Polícia Militar do Paraná, ainda que em fase inicial, com a adoção do Planejamento Estratégico 2022-2035. Verifica-se com esse estudo que, por meio da análise do Plano Estratégico da Polícia Militar de Minas Gerais, a gestão por competências é um processo que começou a ser pensado em 2004 e apenas em 2016 foram tomadas ações maduras e efetivas para sua concretização. Conforme observado, a gestão por competências demanda muitos estudos, planejamento e envolvimentos de toda a gestão de uma Instituição.
Two polymorphic species of the Fe(5-Br-salEen)2ClO4 compound were obtained, each of them being selectively recovered after evaporation of the solvent at a controlled rate. While polymorph 1a is ...formed during slow evaporation, fast evaporation favors polymorph 1b. The importance of the evaporation rate was recognized after detailed studies of the reaction temperature, solvent evaporation rate and crystallization temperature effects. The complex in the new polymorphic form 1a showed an abrupt spin crossover at 172 K with a small 1 K hysteresis window and over a narrow 10 K range. 57Fe Mössbauer spectroscopy and differential scanning calorimetry, complemented by X-ray studies for both the high-spin and low-spin forms, were used to further characterize the new polymorphic phase 1a. Both polymorphs are based on the same Fe(iii) complex cation hydrogen bonded to the perchlorate anion. These units are loosely bound in the crystals via weak interactions. In the new polymorph 1a, the hydrogen bonds are stronger, while the weak hydrogen and halogen bonds, as well as π-π stacking, create a cooperative network, not present in 1b, responsible for the spin transition profile.
Sustainably made, flexible and biocompatible composites, having environmentally friendly compositions and multifunctional capabilities, are promising materials for several emerging biomedical ...applications. Here, the development of flexible and multifunctional chitosan-based bionanocomposites with a mixed reduced graphene oxide-iron oxide (rGO-Fe
3−
x
O
4
) filler is described. The filler is prepared by one-pot synthesis, ensuring good dispersibility of the Fe
3−
x
O
4
nanoparticles and rGO within the chitosan matrix during solvent casting. The resulting bionanocomposites present superparamagnetic response at room temperature. The antioxidant activity is 9 times higher than that of pristine chitosan. The mechanical properties of the films can be tuned from elastic (∼8 MPa) chitosan films to stiff (∼285 MPa) bionanocomposite films with 50% filler. The magnetic hyperthermia tests showed a temperature increase of 40 °C in 45 s for the 50% rGO-Fe
3−
x
O
4
film. Furthermore, the composites have no cytotoxicity to the nontumorigenic (HaCat) cell line, which confirms their biocompatibility and highlights the potential of these materials for biomedical applications, such as hyperthermia treatments.
Sustainably made, flexible and biocompatible composites, having environmentally friendly compositions and multifunctional capabilities, are promising materials for several emerging biomedical applications.
Several ferrocene derivatives (five mononuclear and two binuclear), including the new N-(p-chlorophenyl)-carboxamidoferrocene (1), were synthesized and their anticancer activity investigated. Two of ...them, 3 and 7, bearing a benzimidazole backbone were the most active against HeLa cells achieving IC
50
values of ~5 μM along with 4 with a dipyridylamine ligand (~6 μM). Complex 6, also with a benzimidazole backbone, displayed slightly higher values (~11 μM). Cyclic voltammetry studies show that while the non-cytotoxic ferrocene derivatives 1, 2, and 5 follow a ferrocene-based redox behavior, derivatives 3, 4, 6, and 7 exhibit a more complex mechanism. These complex mechanisms are consistent with a more effective cytotoxic activity. Mössbauer spectroscopy parameters reflect a very small influence of the substituents.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, GIS, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
A pesquisa científica apresentada tem a finalidade de apresentar as ações preventivas da Polícia Militar do Paraná (PMPR) no combate à criminalidade. Na metodologia utilizou-se o enfoque qualitativo ...e como tipo de estudo o descritivo, sendo elaborada uma pesquisa bibliográfica, tendo sido elaborada com base em material já publicado. Inicialmente, aborda a evolução histórica da Segurança Pública, destacando seu papel fundamental na sociedade contemporânea. O embasamento legal é discutido, ressaltando a responsabilidade do Estado e o papel das Polícias Militares, conforme a Constituição Federal. O estudo examina a atuação da PMPR ao longo dos anos, com ênfase em programas preventivos. Explora-se também o conceito de policiamento baseado em evidências para então chegar-se à Companhia Operacional de Recobrimento Preventivo (CORP), como uma iniciativa recente, enfocando atividades preventivas e indicando resultados promissores. Conclui-se, ressaltando que o estudo não representa um encerramento, mas um ponto de partida para análises mais aprofundadas e discussões contínuas, reconhecendo a necessidade de uma abordagem em constante evolução diante das complexidades da segurança pública.
The organometallic fragment MoI2(CO)3 was coordinated to magnetic iron oxide nanoparticles of different sizes (average size of 11 and 30 nm) which have been previously coated with a silica shell and ...grafted with a pyridine derivative ligand. The Mo loading was found to be approximately 0.37 wt-% Mo and 0.57 wt-% Mo, corresponding to 0.150 mmolMo g−1 and 0.230 mmolMo g−1 for materials MNP30-Si-inic-Mo and MNP11-Si-inic-Mo, respectively. Preparation of these organometallic decorated magnetic nanoparticles was further confirmed by evidence obtained from extensive characterization by powder XRD, SEM/TEM analysis, as well as from data of 57Fe Mössbauer and FTIR spectroscopy.
Olefin epoxidation of a variety of substrates promoted by these organometallic nano-hybrid materials using tbhp as oxidant, was performed with very good results. The catalytic studies show that the catalysts yield selectively the desired epoxides of a series of olefins. In addition, these catalysts are found to work under a wide temperature range and over several catalytic cycles without notorious performance loss in most cases.
Magnetic iron nanoparticles of 11 and 30 nm diameter to which Mo organometallic species were anchored. Characterization by powder XRD, SEM/TEM, 57Fe Mössbauer and FTIR confirmed the synthesis. These organometallic nano-hybrid materials are efficient olefin epoxidation catalysts under a wide temperature range and over several catalytic cycles without notorious performance loss. Display omitted
•Magnetic iron oxide nanoparticles of 11 and 30 nm diameter were prepared.•Nanoparticles were coated with silica and then MoI2(CO)3 was coordinated to it.•Mo loading was found to be 0.150 mmolMo g−1 and 0.230 mmolMo g−1 in 11 and 30 nm.•Organometallic nano-hybrid materials are active olefin epoxidation catalysts.•Nanocatalysts perform over a wide temperature range and several catalytic cycles.
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