Direct O mediated oxidation of a Ni(II)NO structural model complex for the active site of nickel acireductone dioxygenase (Ni-ARD): characterization, biomimetic reactivity, and enzymatic implications.

A new biomimetic model complex of the active site of acireductone dioxygenase (ARD) was synthesized and crystallographically characterized (ii1). 1 displays carbon-carbon oxidative cleavage activity in the presence of O towards the substrate 2-hydroxyacetophenone. This reactivity was monitored UV-Visible and NMR spectroscopy.

Cu-Catalyzed Three-Component Alkene Carboamination: Mechanistic Insights and Rational Design to Overcome Limitations.

Herein, we report mechanistic investigations into the Cu-catalyzed three-component carboamination of alkenes with α-halo carbonyls and aryl amines via an oxocarbenium intermediate. Monitoring the reaction reveals the formation of transient atom transfer radical addition (ATRA) intermediates with both electron-neutral and deficient vinyl arenes as well as unactivated alkenes. Based on our experimental studies and density functional theory calculations, the oxocarbenium is generated through atom transfer and subsequent intramolecular substitution.

Multi-phosphine-chelated iron-carbide clusters redox-promoted ligand exchange on an inert hexa-iron-carbide carbonyl cluster, [Fe(μ-C)(μ-CO)(CO)].

We report the reactivity, structures and spectroscopic characterization of reactions of phosphine-based ligands (mono-, di- and tri-dentate) with iron-carbide carbonyl clusters. Historically, the archetype of this cluster class, namely [Fe(μ-C)(μ-CO)(CO)], can be prepared on a gram-scale but is resistant to simple ligand substitution reactions. This limitation has precluded the relevance of iron-carbide clusters relating to organometallics, catalysis and the nitrogenase active site cluster.

A Method for Rigorously Selective Capture and Simultaneous Fluorescent Labeling of N-Terminal Glycine Peptides.

Although chemical methods for the selective derivatization of amino acid (AA) side chains in peptides and proteins are available, selective N-terminal labeling is challenging, especially for glycine, which has no side chain at the α-carbon position. We report here a double activation at glycine's α-methylene group that allows this AA to be differentiated from the other 19 AAs. A condensation reaction of dibenzoylmethane with glycine results in the formation of an imine, and subsequent tautomerization is followed by intramolecular cyclization, leading to the formation of a fluorescent pyrrole ring.

Pervasive loss of regulated necrotic cell death genes in elephants, hyraxes, and sea cows ().

Gene loss can promote phenotypic differences between species, for example, if a gene constrains phenotypic variation in a trait, its loss allows for the evolution of a greater range of variation or even new phenotypes. Here, we explore the contribution of gene loss to the evolution of large bodies and augmented cancer resistance in elephants. We used genomes from 17 Afrotherian and Xenarthran species to identify lost genes, i.

A Janus carbaporphyrin pseudo-dimer.

Carbaporphyrin dimers, investigated for their distinctive electronic structures and exceptional properties, have predominantly consisted of systems containing identical subunits. This study addresses the associated knowledge gap by focusing on asymmetric carbaporphyrin dimers with Janus-like characteristics. The synthesis of a Janus-type carbaporphyrin pseudo-dimer 5 is presented.

Rapid evolution of genes with anti-cancer functions during the origins of large bodies and cancer resistance in elephants.

Elephants have emerged as a model system to study the evolution of body size and cancer resistance because, despite their immense size, they have a very low prevalence of cancer. Previous studies have found that duplication of tumor suppressors at least partly contributes to the evolution of anti-cancer cellular phenotypes in elephants. Still, many other mechanisms must have contributed to their augmented cancer resistance.

Cyclopentadienyl capped thorium(IV) porphyrinoid complex.

The reaction between Th(IV) dipyriamethyrin dichloride and sodium cyclopentadienyl (Cp) results in the formation of a cyclopentadienyl capped thorium dipyriamethyrin complex, which to our knowledge represents the first expanded porphyrin f-element Cp complex.

Nanographene-Fused Expanded Carbaporphyrin Tweezers.

A nanographene-fused expanded carbaporphyrin () and its BF complex () were synthesized. Single-crystal X-ray structures revealed that and are connected by two hexa--hexabenzocoronene (HBC) units and two dipyrromethene or BODIPY units, respectively. As prepared, and both show nonaromatic character with figure-of-eight carbaoctaphyrin (1.

Phylogenomics reveals an almost perfect polytomy among the almost ungulates ().

Phylogenetic studies have resolved most relationships among Orders. However, the branching order of elephants (), hyraxes (), and sea cows () (i.e.

Photochemical charge accumulation in a heteroleptic copper(i)-anthraquinone molecular dyad proton-coupled electron transfer.

Developing efficient photocatalysts that perform multi electron redox reactions is critical to achieving solar energy conversion. One can reach this goal by developing systems which mimic natural photosynthesis and exploit strategies such as proton-coupled electron transfer (PCET) to achieve photochemical charge accumulation. We report herein a heteroleptic Cu(i)bis(phenanthroline) complex, Cu-AnQ, featuring a fused phenazine-anthraquinone moiety that photochemically accumulates two electrons in the anthraquinone unit PCET.

Deferasirox Derivatives: Ligands for the Lanthanide Series.

Deferasirox is an FDA-approved iron chelator used in the treatment of iron toxicity. In this work, we report the use of several deferasirox derivatives as lanthanide chelators. Solid-state structural studies of three representative trivalent lanthanide cations, La(III), Eu(III), and Lu(III), revealed the formation of 2:2 complexes in the solid state.

Diphenylpyrrole-Strapped Calix[4]pyrrole Extractant for the Fluoride and Chloride Anions.

The anion binding features of diphenylpyrrole-strapped calix[4]pyrrole 1 have been investigated by means of H NMR spectroscopy and ITC (isothermal titration calorimetry), as well as single crystal X-ray diffraction analyses. Receptor 1 bearing an auxiliary pyrrolic NH donor and solubilizing phenyl groups on the strap was found to bind F , Cl , and Br as their tetrabutylammonium salts with high affinity in DMSO-d . In addition, receptor 1 was found to extract the fluoride anion (as both its tetraethylammonium (TEA ) and tetrabutylammonium (TBA ) salts), as well as the chloride anion into chloroform-d from an aqueous source phase.

Changing Directions: Influence of Ligand Electronics on the Directionality and Kinetics of Photoinduced Charge Transfer in Cu(I)Diimine Complexes.

A key challenge to the effective utilization of solar energy is to promote efficient photoinduced charge transfer, specifically avoiding unproductive, circuitous electron-transfer pathways and optimizing the kinetics of charge separation and recombination. We hypothesize that one way to address this challenge is to develop a fundamental understanding of how to initiate and control directional photoinduced charge transfer, particularly for earth-abundant first-row transition-metal coordination complexes, which typically suffer from relatively short excited-state lifetimes. Here, we report a series of functionalized heteroleptic copper(I)bis(phenanthroline) complexes, which have allowed us to investigate the directionality of intramolecular photoinduced metal-to-ligand charge transfer (MLCT) as a function of the substituent Hammett parameter.

Optical detection of alcohols with a Cu(I)HETPHEN complex by reversible aldehyde to hemiacetal conversion.

A heteroleptic copper(I) bis(phenanthroline) complex with aldehyde groups at the 4,7 positions of the phenanthroline ligand was synthesized. The complex is responsive to alcohol, resulting in a distinct colour change caused by the facile reaction of the aldehyde group with alcohol, forming a hemiacetal product. The aldehyde species can be regenerated after heating the intermediate at 80 °C for 10 minutes, demonstrating the reusability of the complex for alcohol detection.

Direct Extraction of Sodium Hydroxide by Calix[4]pyrrole-Based Ion-Pair Receptors.

Described in this work are calix[4]pyrrole-based ion-pair receptors, /- and /-, designed for the extraction of sodium hydroxide. An X-ray diffraction analysis of a single crystal of the -·NaOH isomer isolated from a mixture of /- revealed a unique dimeric supramolecular structure. An average dimer in toluene- solution was inferred on the basis of diffusion-ordered spectroscopy (DOSY).

Multifaceted Chiral Probe 2,3-Dihydro-4-hydroxy-chromene Schiff Base in Detecting Cu Ions, l-Histidine, and Indazole: Spectroscopic Investigation and Confocal and Live Cell Imaging.

2,3-Dihydro-4-hydroxy-chromene-4()-ethyl thiosemicarbazone (probe ) is used as a chemosensor, and it selectively detected Cu ions among the metal ions by showing fluorescence "TURN ON" behavior. The stoichiometric binding of the probe with Cu () was confirmed by Job's plot and mass spectroscopy. Further, was used as a sensor for the detection of l-amino acids and N-heterocyclic compounds.

Human embryo implantation.

Embryo implantation in humans is interstitial, meaning the entire conceptus embeds in the endometrium before the placental trophoblast invades beyond the uterine mucosa into the underlying inner myometrium. Once implanted, embryo survival pivots on the transformation of the endometrium into an anti-inflammatory placental bed, termed decidua, under homeostatic control of uterine natural killer cells. Here, we examine the evolutionary context of embryo implantation and elaborate on uterine remodelling before and after conception in humans.

Fluorescent copolymer aggregate sensor for lithium chloride.

We report a copolymeric fluorescent sensor that is selective for lithium chloride. The two constituent polymers comprise pendent triphenylethylene (TPE) moieties for aggregate induced emission (AIE) along with either strapped-calix[4]pyrrole or secondary ammonium groups that drive aggregation self-assembly upon polymer mixing. Addition of LiCl in acetonitrile disrupts the strapped-calix[4]pyrrole/secondary ammonium chloride salt host-guest crosslinks leading to disaggregation of the polymer chains and a decrease in TPE emission.

Elephants as an animal model for self-domestication.

Humans are unique in their sophisticated culture and societal structures, their complex languages, and their extensive tool use. According to the human self-domestication hypothesis, this unique set of traits may be the result of an evolutionary process of self-induced domestication, in which humans evolved to be less aggressive and more cooperative. However, the only other species that has been argued to be self-domesticated besides humans so far is bonobos, resulting in a narrow scope for investigating this theory limited to the primate order.

Interpreting the Evolutionary Echoes of a Protein Complex Essential for Inner-Ear Mechanosensation.

The sensory epithelium of the inner ear, found in all extant lineages of vertebrates, has been subjected to over 500 million years of evolution, resulting in the complex inner ear of modern vertebrates. Inner-ear adaptations are as diverse as the species in which they are found, and such unique anatomical variations have been well studied. However, the evolutionary details of the molecular machinery that is required for hearing are less well known.

Cyclo[2]carbazole[2]pyrrole: a preorganized calix[4]pyrrole analogue.

A cyclo[2]carbazole[2]pyrrole (2) consisting of two carbazoles and two pyrroles has been synthesized by directly linking the carbazole 1- and 8-carbon atoms to the pyrrole α-carbon atoms. Macrocycle 2 is an extensively conjugated 16-membered macrocyclic ring that is fixed in a pseudo-1,3-alternate conformation. This provides a preorganized anion binding site consisting of two pyrrole subunits.

Cyclic Carbaporphyrin Arrays.

Two cyclic carbaporphyrin arrays (trimer and tetramer ) were synthesized from a dibrominated carbaporphyrin precursor () via a one-pot Yamamoto-type coupling. Single-crystal X-ray diffraction analyses revealed that and contain three and four covalently linked carbaporphyrin (formally dicarbacorrole) units, respectively. Trimer adopts a roughly planar conformation and tetramer adopts an up-and-down zig-zag conformation.

Supramolecular Recognition within a Nanosized "Buckytrap" That Exhibits Substantial Photoconductivity.

We report here a nanosized "buckytrap", , constructed from two bis-zinc(II) expanded-TTF (exTTF) porphyrin subunits. Two forms, and , differing in the axial ligands, HO vs tetrahydrofuran (THF), were isolated and characterized. Discrete host-guest inclusion complexes are formed upon treatment with fullerenes as inferred from a single-crystal X-ray structural analyses of with C.

Parallel evolution of reduced cancer risk and tumor suppressor duplications in .

The risk of developing cancer is correlated with body size and lifespan within species, but there is no correlation between cancer and either body size or lifespan between species indicating that large, long-lived species have evolved enhanced cancer protection mechanisms. Previously we showed that several large bodied lineages evolved reduced intrinsic cancer risk, particularly elephants and their extinct relatives (), coincident with pervasive duplication of tumor suppressor genes (Vazquez and Lynch, 2021). Unexpectedly, we also found that (sloths, armadillos, and anteaters) evolved very low intrinsic cancer risk.