Some new chiral substituted ferrocenyl bismuthines CpFe(2-{Me2NCH(R)}C5H3)BiPhCl where R = H (1) or Me (2) and CpFe(2-{Me2NCH(R)}C5H3)BiPh2 where R = H (3) or Me (4) (Cp = cyclopentadienyl) ...containing 2-(Me2NCH(R) pendant arm on the ferrocenyl ring were synthesized by the reaction of PhBiCl2 or Ph2BiCl with CpFe(2-{Me2NCH(R)}C5H3)Li in a 1:1 M ratio respectively. The Ammonium salt of compound (3) was used as a starting material to modify the nature of the pendant arm. All the new compounds were characterized by 1H NMR, 13C spectroscopy, FAB+, and High-Resolution Mass Spectrometry. All the compounds presented in this work show planar chirality because of 1,2-disubstituted ferrocene. In the solid-state, the presence of the ferrocenyl group influences the stereoelectronic properties in the molecule and Bi···N hypervalent interaction could not be observed in diphenyl bismuthines and was observed.
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•Synthesis of new 1,2-disubstituted Ferrocenyl-Bismuthines containing N/O donor pendant arm in ligands.•Substituent effects on the observed bismuth hypervalency.•VT NMR and X-ray structure of 1,2-disubstituted Ferrocenyl-Bismuthines.
Some new chiral substituted ferrocenyl bismuthines CpFe(2-Me2NCH(R)C5H3)BiPhCl where R = H (1) or Me (2) and CpFe(2-Me2NCH(R)C5H3)BiPh2 where R = H (3) or Me (4) (Cp = cyclopentadienyl) containing a Rac-2-(Me2NCH(R) pendant arm on the ferrocenyl ring were synthesized. Nucleophilic substitution reaction of mono ammonium salt Rac-{CpFe{2-(Me3N+CH2)C5H3}BiPh2I− (5) by o-hydroxyacetaphenone, salicyladehyde, N-methylpiperazine and 4′- aminobenzo-15-crown-5 in acetonitrile gave new ferrocenyl bismuthines CpFe{2-(RCH2)C5H3}BiPh2 where R = OC6H4-2-C(O)Me (6), OC6H4-2-C(O)H (7), N(CH2CH2)2NMe (8) and NHC6H4-3,4-O-cyclo{(CH2)2-O}4 (9) respectively with N or O containing pendant arm. All the new compounds were characterized by 1H NMR, 13C NMR, FAB+, and High-Resolution Mass Spectrometry. All the compounds presented in this work present planar chirality because of 1,2-disubstituted ferrocene. In the solid-state, the presence of the ferrocenyl group influences the stereoelectronic properties in the molecule and Bi···N or Bi···O hypervalent interaction could not be observed in compounds with BiPh2 fragment while this interaction was observed in compounds with BiPhCl fragment. For compounds (1)-(4), (6)-(8) and (10), NMR spectra obtained at different temperatures show the association and/or dissociation of hypervalent N···Bi coordination in these compounds. Molecular structures of compounds (1), (2) and (10) show distorted pseudo-trigonal bipyramidal geometry (see-saw structure) at bismuth center with intramolecular Bi···N hypervalent interaction while (6) and (7) present a distorted pseudo-trigonal pyramidal geometry and do not show hypervalent Bi···O interaction. Crystal structures of these compounds show that CFc-Bi bond length is shorter than CPh-Bi bond length due to lower group electronegativity of ferrocenyl vs phenyl and bidentate nature of FcN ligand in ferrocenyl bismuthines.
New tertiary ferrocenyl stibines (
I
and
III
) and bismuthine (
II
) have been synthesized. All these compounds have been characterized by IR, MS, and NMR spectroscopy and the molecular structures of
...I
–
III
have been determined by X-ray crystallography. Compounds
I
–
III
have also been studied by cyclic voltammetry (CV). Crystal structures of homoleptic stibine and bismuthine (
I
,
II
) adopt a “propeller” configuration with the three ferrocenyl groups tilted to minimize interatomic repulsion and exhibit helicoidal chirality. The structures of
I
and
III
show that both the stibines exhibit an intramolecular C−H···C interaction. The voltammograms of stibines show that
E
1/2
values are more positive than that of ferrocene indicating that oxidation of Fc
3
Sb is slightly more challenging in comparison to ferrocene. Triferrocenyl bismuthine (
II
) displays two redox waves with low resolution and a non-reversible process.
We present an analysis of observed trends and correlations between a large range of spectral and photometric parameters of more than 100 type II supernovae (SNe II), during the photospheric phase. We ...define a common epoch for all SNe of 50 days post-explosion, where the majority of the sample is likely to be under similar physical conditions. Several correlation matrices are produced to search for interesting trends between more than 30 distinct light-curve and spectral properties that characterize the diversity of SNe II. Overall, SNe with higher expansion velocities are brighter, have more rapidly declining light curves, shorter plateau durations, and higher 56Ni masses. Using a larger sample than previous studies, we argue that “Pd”—the plateau duration from the transition of the initial to “plateau” decline rates to the end of the “plateau”—is a better indicator of the hydrogen envelope mass than the traditionally used optically thick phase duration (OPTd: explosion epoch to end of plateau). This argument is supported by the fact that Pd also correlates with s 3, the light-curve decline rate at late times: lower Pd values correlate with larger s 3 decline rates. Large s 3 decline rates are likely related to lower envelope masses, which enables gamma-ray escape. We also find a significant anticorrelation between Pd and s 2 (the plateau decline rate), confirming the long standing hypothesis that faster declining SNe II (SNe IIL) are the result of explosions with lower hydrogen envelope masses and therefore have shorter Pd values.
Aims. We present and study the spectroscopic and photometric evolution of the type Ia supernova (SN Ia) 2010ev. Methods. We obtain and analyze multiband optical light curves and optical/near-infrared ...spectroscopy at low and medium resolution spanning −7 days to +300 days from the B-band maximum. Results. A photometric analysis shows that SN 2010ev is a SN Ia of normal brightness with a light-curve shape of Δm15(B) = 1.12 ± 0.02 and a stretch s = 0.94 ± 0.01 suffering significant reddening. From photometric and spectroscopic analysis, we deduce a color excess of E(B − V) = 0.25 ± 0.05 and a reddening law of Rv = 1.54 ± 0.65. Spectroscopically, SN 2010ev belongs to the broad-line SN Ia group, showing stronger than average Si iiλ6355 absorption features. We also find that SN 2010ev is a high velocity gradient SN with v̇Si = 164 ± 7 km s-1 d-1. The photometric and spectral comparison with other supernovae shows that SN 2010ev has similar colors and velocities to SN 2002bo and SN 2002dj. The analysis of the nebular spectra indicates that the Fe iiλ7155 and Ni iiλ7378 lines are redshifted, as expected for a high velocity gradient supernova. All these common intrinsic and extrinsic properties of the high velocity gradient (HVG) group are different from the low velocity gradient (LVG) normal SN Ia population and suggest significant variety in SN Ia explosions.
•Parenteral nutrition represents a therapeutic option for patients with type 3 intestinal failure; if used exclusively, parenteral nutrition must be complete to provide all essential nutrients.•An ...international survey using an electronic questionnaire was conducted in August 2019 and repeated in May 2022; 36 country representatives responded.•The study reported on the high availability of parenteral nutrition worldwide.•Shortages may have a substantial effect on the quality of parenteral nutrition admixtures.•Conflicts of interest: Stanislaw Klek acts as a lecturer and consultant for B Braun, Fresenius Kabi, Nutricia Polska Ltd., Nestle, Baxter, and Takeda. Stephane M. Schneider acts as a speaker, advisory board member, and researcher with B. Braun, Baxter, and Fresenius-Kabi. The other authors declare no potential or actual personal, political, or financial interest in the material, information, or techniques described in the article.
Parenteral nutrition represents a therapeutic option for patients with type 3 intestinal failure. If used exclusively, parenteral nutrition has to be complete to provide all essential nutrients. The aim was to assess the availability of parenteral nutrition in all parts of the world, to better comprehend the global situation, and to prepare an action plan to increase access to parenteral nutrition.
An international survey using an electronic questionnaire was conducted in August 2019 and repeated in May 2022. An electronic questionnaire was sent to 52 members or affiliates of the International Clinical Nutrition Section of the American Society for Parenteral and Enteral Nutrition. Questions addressed the availability of parenteral nutrition admixtures and their components, reimbursement, and prescribing pre- and post-COVID-19 pandemic. All participating countries were categorized by their economic status.
Thirty-six country representatives responded, answering all questions. Parenteral nutrition was available in all countries (100%), but in four countries (11.1%) three-chamber bags were the only option, and in six countries a multibottle system was still used. Liver-sparing amino acids were available in 18 (50%), kidney-sparing in eight (22.2%), and electrolyte-free in 11 (30.5%) countries (30.5%). In most countries (n = 28; 79.4%), fat-soluble and water-soluble vitamins were available. Trace elements solutions were unavailable in four (11.1%) countries. Parenteral nutrition was reimbursed in most countries (n = 33; 91.6%). No significant problems due to the coronavirus pandemic were reported.
Despite the apparent high availability of parenteral nutrition worldwide, there are some factors that may have a substantial effect on the quality of parenteral nutrition admixtures. These shortages create an environment of inequality.
Abstract
We present observations of three core-collapse supernovae (CCSNe) in elliptical hosts, detected by the Zwicky Transient Facility Bright Transient Survey (BTS). SN 2019ape is a SN Ic that ...exploded in the main body of a typical elliptical galaxy. Its properties are consistent with an explosion of a regular SN Ic progenitor. A secondary
g
-band light-curve peak could indicate interaction of the ejecta with circumstellar material (CSM). An H
α
-emitting source at the explosion site suggests a residual local star formation origin. SN 2018fsh and SN 2020uik are SNe II which exploded in the outskirts of elliptical galaxies. SN 2020uik shows typical spectra for SNe II, while SN 2018fsh shows a boxy nebular H
α
profile, a signature of CSM interaction. We combine these 3 SNe with 7 events from the literature and analyze their hosts as a sample. We present multi-wavelength photometry of the hosts, and compare this to archival photometry of all BTS hosts. Using the spectroscopically complete BTS, we conclude that
0.3
%
−
0.1
+
0.3
of all CCSNe occur in elliptical galaxies. We derive star formation rates and stellar masses for the host galaxies and compare them to the properties of other SN hosts. We show that CCSNe in ellipticals have larger physical separations from their hosts compared to SNe Ia in elliptical galaxies, and discuss implications for star-forming activity in elliptical galaxies.
The low-luminosity Type II SN2016aqf Müller-Bravo, Tomás E.; Gutiérrez, Claudia P.; Sullivan, Mark ...
Monthly notices of the Royal Astronomical Society,
09/2020, Letnik:
497, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Low-luminosity Type II supernovae (LL SNe II) make up the low explosion energy end of core-collapse SNe, but their study and physical understanding remain limited. We present SN 2016aqf, an LL SN II ...with extensive spectral and photometric coverage. We measure a V -band peak magnitude of −14.58 mag, a plateau duration of ∼100 d, and an inferred 56 Ni mass of 0.008 ± 0.002 M ⊙ . The peak bolometric luminosity, L bol ≈ 10 41.4 erg s −1 , and its spectral evolution are typical of other SNe in the class. Using our late-time spectra, we measure the O i λλ6300, 6364 lines, which we compare against SN II spectral synthesis models to constrain the progenitor zero-age main-sequence mass. We find this to be 12 ± 3 M ⊙ . Our extensive late-time spectral coverage of the Fe ii λ7155 and Ni ii λ7378 lines permits a measurement of the Ni/Fe abundance ratio, a parameter sensitive to the inner progenitor structure and explosion mechanism dynamics. We measure a constant abundance ratio evolution of 0.081+0.009−0.010 and argue that the best epochs to measure the ratio are at ∼200–300 d after explosion. We place this measurement in the context of a large sample of SNe II and compare against various physical, light-curve, and spectral parameters, in search of trends that might allow indirect ways of constraining this ratio. We do not find correlations predicted by theoretical models; however, this may be the result of the exact choice of parameters and explosion mechanism in the models, the simplicity of them, and/or primordial contamination in the measured abundance ratio.
Synthesis of new 1,2 disubstituted ferrocenylated selenoether and telluroether ligands, that contain other donor groups Oxygen and Nitrogen and their respective palladium complexes were synthesized. ...The ligands and their palladium complexes were characterized by elemental analysis, (1H, 13C, 77Se or 125Te) NMR, variable temperature NMR studies and IR, UV–vis spectroscopy, mass spectrometry, and cyclic voltammetry. The molecular structures of all the palladium complexes were determined by X-ray crystallography which confirms that these ligands act in a bidentate fashion.
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The 1,2 disubstituted ferrocenylated unsymmetrical potentially tridentate selenoether and telluroether ligands, containing Oxygen and Nitrogen at the other donor sites and their respective palladium complexes were synthesized. The molecular structures of all the palladium complexes were determined by X-ray crystallography which confirms that these ligands coordinate in a bidentate fashion. The structures show intramolecular and intermolecular interactions type E···E, E···O, CH···Cl, and E···Cl interactions (E = Se or Te). Interestingly chalcogenoether ligands containing the 3-hydroxy propyl group and their palladium complexes are soluble in water and 1H NMR spectra of these ligands do not show OH proton signal at room temperature but at low temperature broad deshielded proton signal confirms the involvement of –OH group in secondary interactions with Se or Te atom as an intramolecular chalcogen bonding. The cyclic voltammograms of selenoether and their complexes present single reversible and quasi reversible waves while telluroether ligands present three quasi reversible processes and their complexes show three nonreversible redox processes.
SN 2019hcc Parrag, Eleonora; Inserra, Cosimo; Schulze, Steve ...
Monthly notices of the Royal Astronomical Society,
10/2021, Letnik:
506, Številka:
4
Journal Article
Recenzirano
Odprti dostop
We present optical spectroscopy together with ultraviolet, optical, and near-infrared photometry of SN 2019hcc, which resides in a host galaxy at redshift 0.044, displaying a sub-solar metallicity. ...The supernova spectrum near peak epoch shows a ‘w’ shape at around 4000 Å which is usually associated with O II lines and is typical of Type I superluminous supernovae. SN 2019hcc post-peak spectra show a well-developed H α P-Cygni profile from 19 d past maximum and its light curve, in terms of its absolute peak luminosity and evolution, resembles that of a fast-declining Hydrogen-rich supernova (SN IIL). The object does not show any unambiguous sign of interaction as there is no evidence of narrow lines in the spectra or undulations in the light curve. Our TARDIS spectral modelling of the first spectrum shows that carbon, nitrogen, and oxygen (CNO) at 19 000 K reproduce the ‘w’ shape and suggests that a combination of non-thermally excited CNO and metal lines at 8000 K could reproduce the feature seen at 4000 Å. The Bolometric light-curve modelling reveals that SN 2019hcc could be fit with a magnetar model, showing a relatively strong magnetic field (B > 3 × 10 14 G), which matches the peak luminosity and rise time without powering up the light curve to superluminous luminosities. The high-energy photons produced by the magnetar would then be responsible for the detected Oɪɪ lines. As a consequence, SN 2019hcc shows that a ‘w’ shape profile at around 4000 Å, usually attributed to O II, is not only shown in superluminous supernovae and hence it should not be treated as the sole evidence of the belonging to such a supernova type.
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