384 research outputs found
Synthese und ReaktivitĂ€t von trigonalen Imido-Komplexen der spĂ€ten Ăbergangsmetalle
Im Rahmen dieser Doktorarbeit wurden die Synthese und das Reaktionsverhalten
von niedrig koordinierten Imido-Komplexen des Cobalts und Nickels untersucht.
Insgesamt konnte ich zeigen, dass lineare Metall(I)silylamide als vielseitige Komplexplattformen
fĂŒr die Darstellung von trigonalen Imido-Komplexen in höheren
SpinzustÀnden geeignet sind. Diese erweisen sich als zum Teil hochreaktiv und erlauben
tiefe Einblicke in die vielfÀltige Imido-Metall-Bindungssituation. Die dabei
gewonnenen Erkenntnisse sind wegweisend fĂŒr eine vollstĂ€ndiges VerstĂ€ndnis von
Nitren-Transfer-Reaktionen
TELEMEDICINA NA PERSPECTIVA DA DIGNIDADE DA PESSOA HUMANA: DA VISĂO NACIONAL A LOCAL NO OESTE DE SANTA CATARINA
A pesquisa tem como objetivo conhecer e debater a respeito da telemedicina, considerando as modificaçÔestrazidas ao exercĂcio da medicina, bem como ao acesso dos pacientes, especialmente na regiĂŁo oeste de Santa Catarina, relacionando com a dignidade humana
Threeâdimensional phenotyping of peach treeâcrown architecture utilizing terrestrial laser scanning
Abstract Tree training systems for temperate fruit have been developed throughout history by pomologists to improve light interception, fruit yield, and fruit quality. These training systems direct crown and branch growth to specific configurations. Quantifying crown architecture could aid the selection of trees that require less pruning or that naturally excel in specific growing/training system conditions. Regarding peaches [Prunus persica (L.) Batsch], access tools such as branching indices have been developed to characterize treeâcrown architecture. However, the required branching data (BD) to develop these indices are difficult to collect. Traditionally, BD have been collected manually, but this process is tedious, timeâconsuming, and prone to human error. These barriers can be circumnavigated by utilizing terrestrial laser scanning (TLS) to obtain a digital twin of the real tree. TLS generates threeâdimensional (3D) point clouds of the tree crown, wherein every point contains 3D coordinates (x, y, z). To facilitate the use of these tools for peach, we selected 16 young peach trees scanned in 2021 and 2022. These 16 trees were then modeled and quantified using the openâsource software TreeQSM. As a result, âin silicoâ branching and biometric data for the young peach trees were calculated to demonstrate the capabilities of TLS phenotyping of peach treeâcrown architecture. The comparison and analysis of field measurements (in situ) and in silico BD, biometric data, and quantitative structural model branch uncertainty data were utilized to determine the reconstructive model's reliability as a source substitute for field measurements. Mean average deviation when comparing young tree (YT) height was approx. 5.93%, with crown volume was approx. 13.26% across both 2021 and 2022. All point clouds of the YTs in 2022 showed residuals lower than 12Â mm to cylinders fitted to all branches, and mean surface coverage greater than 40% for both the trunk and primary branching orders
Imido Cobalt Complexes with Imidyl Character
We report on the synthesis of a variety of trigonal imido cobalt complexes [Co(NAryl)L2)â, (L = N(Dipp)SiMe3), Dipp = 2,6-diisopropylphenyl) bearing very long CoâNAryl bonds of around 1.75 Ă
. The electronic structure was interrogated using a variety of physical and spectroscopic methods indicating the first authenticated examples of cobalt bound imidyl species. Computational studies corroborate these findings and reveal that the high-spin state of these complexes gives rise to unpaired spin-density on the imide nitrogen and leads to its imidyl character. Obtained complexes are capable of intermolecular H atom abstraction from CâH bonds that yields the corresponding cobalt amides. Exchange of the Dipp-substituent on the imide by the smaller mesityl function (2,4,6-trimethylphenyl) effectuates the unexpected Me3Si shift from the ancillary ligand set to the imide nitrogen, followed by intramolecular CâH bond activation.<br /
High-Spin Imido Cobalt Complexes with Imidyl Radical Character
We report on the synthesis of a variety of trigonal imido cobalt complexes [Co(NAryl)L2]â, (L=N(Dipp)SiMe3), Dipp=2,6-diisopropylphenyl) with very long CoâNAryl bonds of around 1.75â
Ă
. Their electronic structure was interrogated using a variety of physical and spectroscopic methods such as EPR or X-Ray absorption spectroscopy which leads to their description as highly unusual imidyl cobalt complexes. Computational analyses corroborate these findings and further reveal that the high-spin state is responsible for the imidyl character. Exchange of the Dipp substituent on the imide by the smaller mesityl function (2,4,6-trimethylphenyl) effectuates the unexpected Me3Si shift from the ancillary ligand set to the imidyl nitrogen, revealing a highly reactive, nucleophilic character of the imidyl unit
Between imide, imidyl and nitrene â an imido iron complex in two oxidation states
Imidyl and nitrene metal species play an important role in the N-functionalisation of unreactive CâH bonds
as well as the aziridination of olefines. We report on the synthesis of the trigonal imido iron complexes
[Fe(NMes)L2]0,- (L ÂŒ âN{Dipp}SiMe3); Dipp ÂŒ 2,6-diisopropyl-phenyl; Mes ÂŒ (2,4,6-trimethylphenyl) via
reaction of mesityl azide (MesN3) with the linear iron precursors [FeL2]0,-. UV-vis-, EPR-, 57Fe Mšossbauer
spectroscopy, magnetometry, and computational methods suggest for the reduced form an electronic
structure as a ferromagnetically coupled iron(II) imidyl radical, whereas oxidation leads to mixed iron(III)
imidyl and electrophilic iron(II) nitrene character. Reactivity studies show that both complexes are
capable of H atom abstraction from CâH bonds. Further, the reduced form [Fe(NMes)L2]- reacts
nucleophilically with CS2 by inserting into the imido iron bond, as well as electrophilically with CO under
nitrene transfer. The neutral [Fe(NMes)L2] complex shows enhanced electrophilic behavior as evidenced
by nitrene transfer to a phosphine, yet in combination with an overall reduced reactivity
Between imide, imidyl and nitrene â an imido iron complex in two oxidation states
Imidyl and nitrene metal species play an important role in the N-functionalisation of unreactive CâH bonds as well as the aziridination of olefines. We report on the synthesis of the trigonal imido iron complexes [Fe(NMes)L2]0,â (L = âN{Dipp}SiMe3); Dipp = 2,6-diisopropyl-phenyl; Mes = (2,4,6-trimethylphenyl) via reaction of mesityl azide (MesN3) with the linear iron precursors [FeL2]0,â. UV-vis-, EPR-, 57Fe Mössbauer spectroscopy, magnetometry, and computational methods suggest for the reduced form an electronic structure as a ferromagnetically coupled iron(II) imidyl radical, whereas oxidation leads to mixed iron(III) imidyl and electrophilic iron(II) nitrene character. Reactivity studies show that both complexes are capable of H atom abstraction from CâH bonds. Further, the reduced form [Fe(NMes)L2]â reacts nucleophilically with CS2 by inserting into the imido iron bond, as well as electrophilically with CO under nitrene transfer. The neutral [Fe(NMes)L2] complex shows enhanced electrophilic behavior as evidenced by nitrene transfer to a phosphine, yet in combination with an overall reduced reactivity
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