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The Seyfert galaxy NGC 2639 was known to exhibit three episodes of active galactic nuclei (AGN) jet/lobe activity. We present here the upgraded Giant Metrewave Radio Telescope (uGMRT) 735 MHz image of NGC 2639 showing a fourth episode as witnessed by the discovery of ∼9 kpc radio lobes misaligned with the previously known ∼1.5 kpc, ∼360 pc, and ∼3 pc jet features detected through the Karl G. Jansky Very Large Array (VLA) and the Very Long Baseline Array (VLBA), respectively. Using the spectral ageing software brats, we derive the ages of the ∼9 kpc, ∼1.5 kpc, and ∼360 pc episodes to be, respectively, $34^{+4}_{-6}$, $11.8^{+1.7}_{-1.4}$, and $2.8^{+0.7}_{-0.5}$ Myr, and conclude that minor mergers occurred 9−22 Myr apart. NGC 2639 shows a deficit of molecular gas in its central ∼6 kpc region. The GALEX NUV image also shows a deficiency of recent star formation in the same region, while the star formation rate surface density in NGC 2639 is lower by a factor of 5−18 compared to the global Schmidt law of star-forming galaxies. This makes NGC 2639 a rare case of a Seyfert galaxy showing episodic jet activity and possible signatures of jet-driven AGN feedback.

 

Transient absorption data of [Fe II (tpy)(CN) 3 ] − reveals spectroscopic signatures indicative of 3 MLCT with a ∼10 ps kinetic component. These data are supported by DFT and TD-DFT calculations, which show that excited state ordering is responsive to the number of cyanide ligands on the complex. 

We report the excited-state behavior of a structurally simple bis -sulfoxide complex, cis -S,S-[Ru(bpy) 2 (dmso) 2 ] 2+ , as investigated by femtosecond pump–probe spectroscopy. The results reveal that a single photon prompts phototriggered isomerization of one or both dmso ligands to yield a mixture of cis -S,O-[Ru(bpy) 2 (dmso) 2 ] 2+ and cis -O,O-[Ru(bpy) 2 (dmso) 2 ] 2+ . The quantum yields of isomerization of each product and relative product distribution are dependent upon the excitation wavelength, with longer wavelengths favoring the double isomerization product, cis -O,O-[Ru(bpy) 2 (dmso) 2 ] 2+ . Transient absorption measurements on cis -O,O-[Ru(bpy) 2 (dmso) 2 ] 2+ do not reveal an excited-state isomerization pathway to produce either the S,O or S,S isomers. Femtosecond pulse shaping experiments reveal no change in the product distribution. Pump–repump–probe transient absorption spectroscopy of cis -S,S-[Ru(bpy) 2 (dmso) 2 ] 2+ shows that a pump–repump time delay of 3 ps dramatically alters the S,O : O,O product ratio; pump–repump–probe transient absorption spectroscopy of cis -O,O-[Ru(bpy) 2 (dmso) 2 ] 2+ with a time delay of 3 ps uncovers an excited-state isomerization pathway to produce the S,O isomer. In conjunction with low-temperature steady-state emission spectroscopy, these results are interpreted in the context of an excited-state bifurcating pathway, in which the isomerization product distribution is determined not by thermodynamics, but rather as a dynamics driven reaction. 

A new pyridine-bis(carboxamide)-based ligand with a bithiophene pendant, 2Tcbx, was synthesized. Its lanthanide ion (Ln III ) complexes, [Ln(2Tcbx) 2 ] 3+ , were isolated and their photophysical properties were explored. Upon excitation at 360 nm, these complexes display emission in the near-infrared (NIR) with efficiencies of 0.69% for Ln III = Yb III , 0.20% for Ln III = Nd III , and 0.01% for Ln III = Er III , respectively. Concurrent 1 O 2 formation was seen for all complexes, with efficiencies of 19% for the Yb III complex, 25% for the Nd III complex, and 9% for the Er III complex. When exciting at a longer wavelength, 435 nm, only Ln III emission was observed and larger efficiencies of Ln III -centered emission were obtained. The lack of 1 O 2 generation indicates that energy pathways involving different ligand conformations, which were investigated by transient absorption spectroscopy, are involved in the sensitization process, and enable the wavelength-dependent generation of 1 O 2 . 

ABSTRACT We present the first high-resolution 230–470 MHz map of the Perseus cluster obtained with the Karl G. Jansky Very Large Array. The high dynamic range and resolution achieved have allowed the identification of previously unknown structures in this nearby galaxy cluster. New hints of sub-structures appear in the inner radio lobes of the brightest cluster galaxy NGC 1275. The spurs of radio emission extending into the outer X-ray cavities, inflated by past nuclear outbursts, are seen for the first time at these frequencies, consistent with spectral aging. Beyond NGC 1275, we also analyse complex radio sources harboured in the cluster. Two new distinct, narrowly collimated jets are visible in IC 310, consistent with a highly projected narrow-angle tail radio galaxy infalling into the cluster. We show how this is in agreement with its blazar-like behaviour, implying that blazars and bent-jet radio galaxies are not mutually exclusive. We report the presence of filamentary structures across the entire tail of NGC 1265, including two new pairs of long filaments in the faintest bent extension of the tail. Such filaments have been seen in other cluster radio sources such as relics and radio lobes, indicating that there may be a fundamental connection between all these radio structures. We resolve the very narrow and straight tail of CR 15 without indication of double jets, so that the interpretation of such head–tail sources is yet unclear. Finally, we note that only the brightest western parts of the mini-halo remain, near NGC 1272 and its bent double jets. 

Reductive electrosynthesis has faced long-standing challenges in applications to complex organic substrates at scale. Here, we show how decades of research in lithium-ion battery materials, electrolytes, and additives can serve as an inspiration for achieving practically scalable reductive electrosynthetic conditions for the Birch reduction. Specifically, we demonstrate that using a sacrificial anode material (magnesium or aluminum), combined with a cheap, nontoxic, and water-soluble proton source (dimethylurea), and an overcharge protectant inspired by battery technology [tris(pyrrolidino)phosphoramide] can allow for multigram-scale synthesis of pharmaceutically relevant building blocks. We show how these conditions have a very high level of functional-group tolerance relative to classical electrochemical and chemical dissolving-metal reductions. Finally, we demonstrate that the same electrochemical conditions can be applied to other dissolving metal–type reductive transformations, including McMurry couplings, reductive ketone deoxygenations, and epoxide openings.