Iron homo- and heterobimetallic complexes supported by a symmetrical dinucleating ligand.

The selective synthesis of biomimetic Fe/Mn complexes able to mimic the geometry and catalytic activity of enzymes possessing this cofactor is still a challenge. Herein, we discuss the stepwise synthesis, characterization, and magnetic properties of a Fe(II)/Mn(II) species and related Fe(II)/Fe(II) complexes.

Dysexecutive symptomatology in everyday functioning and academic achievement in adolescents.

Background: During the educational stage, academic achievement depends on various social, family, and personal factors. Among the latter, executive skills in everyday life play a significant role in dealing with the academic demands of adolescents. Therefore, the aim of this study is to ascertain the effects of executive symptomatology in everyday functioning on academic achievement in adolescents.

Diborane Reductions of CO and CS Mediated by Dicopper μ-Boryl Complexes of a Robust Bis(phosphino)-1,8-naphthyridine Ligand.

A dinucleating 1,8-naphthyridine ligand featuring fluorene-9,9-diyl-linked phosphino side arms (PNNP) was synthesized and used to obtain the cationic dicopper complexes , [(PNNP)Cu(μ-Ph)][NTf]; [NTf] = bis(trifluoromethane)sulfonimide, , [(PNNP)Cu(μ-CCPh)][NTf], and , [(PNNP)Cu(μ-OBu)][NTf]. Complex reacted with diboranes to afford dicopper μ-boryl species (, with μ-Bcat; cat = catecholate and , with μ-Bpin; pin = pinacolate) that are more reactive in C(sp)-H bond activations and toward activations of CO and CS, compared to dicopper μ-boryl complexes supported by a 1,8-naphthyridine-based ligand with di(pyridyl) side arms. The solid-state structures and DFT analysis indicate that the higher reactivities of and relate to changes in the coordination sphere of copper, rather than to perturbations on the Cu-B bonding interactions.

Electrophilic Hydrosilylation of Electron-Rich Alkenes Derived from Enamines.

The low-electron count, air-stable, platinum complexes [Pt(IBu')(IBu)][BAr] (C1) (IBu=1,3-di-tert-butylimidazol-2-ylidene), [Pt(SiPh)(IBuPr)][BAr] (C2) (IBuPr=1-tert-butyl-3-iso-propylimidazol-2-ylidene), [Pt(SiPh)(IBuMe)][BAr] (C3), [Pt(GePh)(IBuPr)][BAr] (C4), [Pt(GePh)(IBuMe)][BAr] (C5) and [Pt(GeEt)(IBuMe)][BAr] (C6) (IBuMe=1-tert-butyl-3-methylimidazol-2-ylidene) are efficient catalysts (particularly the germyl derivatives) in both the silylative dehydrocoupling and hydrosilylation of electron rich alkenes derived from enamines. The steric hindrance exerted by the NHC ligand plays an important role in the selectivity of the reaction. Thus, bulky ligands are selective towards the silylative dehydrocoupling process whereas less sterically hindered promote the selective hydrosilylation reaction.

Tetracopper σ-Bound μ-Acetylide and -Diyne Units Stabilized by a Naphthyridine-based Dinucleating Ligand.

Reactions of a dicopper(I) tert-butoxide complex with alkynes possessing boryl or silyl capping groups resulted in formation of unprecedented tetracopper(I) μ-acetylide/diyne complexes that were characterized by NMR and UV/Vis spectroscopy, mass spectrometry and single-crystal X-ray diffraction. These compounds possess an unusual μ -η :η :η :η coordination mode for the bridging organic fragment, enforced by the rigid and dinucleating nature of the ligand utilized. Thus, the central π system remains unperturbed and accessible for subsequent reactivity and modification.

Peptides as Baits for the Coprecipitation of SH2 Domain-Containing Proteins.

Phosphotyrosine (pTyr)-containing amino acid sequences have regulatory effects on proteins that contain pTyr recognition motifs, such as Src Homology 2 (SH2) domains. Using pTyr-containing peptides as a bait for coprecipitation, by immobilization of the synthesized phosphopeptides to beads and incubation with cell lysates, enables to study the binding preference of the SH2 domain for the specific pTyr-sequence obtained from a pTyr-containing protein in a complex biological environment. Using phosphopeptides allows to not only assess the wild-type sequence, but also peptides that can contain modified sequences which carry a nonhydrolyzable pTyr or other modifications varying the binding strength and selectivity, for example, to create strong SH2 domain binders to inhibit their interaction with pTyr-containing proteins.

Measuring Protein Tyrosine Phosphatase Activity Dependent on SH2 Domain-Mediated Regulation.

Src-homology-2 (SH2) domains bind selectively to phosphotyrosine (pTyr) residues located in target binding proteins; therefore, they are key elements in pTyr-mediated signaling pathways. The binding of an SH2 domain to a pTyr acts as a docking mechanism that attracts proteins into signaling hubs, and in some cases, it can also regulate the catalytic activity of signaling enzymes such as protein kinases or protein phosphatases. Therefore, compounds that selectively bind SH2 domains can be potentially used to modulate the activity of such SH2 domain-containing enzymes.

Cleavage of Carbon Dioxide C=O Bond Promoted by Nickel-Boron Cooperativity in a PBP-Ni Complex.

The synthesis and characterization of ( PBP)Ni(OAc) (5) by insertion of carbon dioxide into the Ni-C bond of ( PBP)NiMe (1) is presented. An unexpected CO cleavage process involving the formation of new B-O and Ni-CO bonds leads to the generation of a butterfly-structured tetra-nickel cluster ( PBOP) Ni (μ-CO) (6). Mechanistic investigation of this reaction indicates a reductive scission of CO by O-atom transfer to the boron atom via a cooperative nickel-boron mechanism.

TREXIO: A file format and library for quantum chemistry.

TREXIO is an open-source file format and library developed for the storage and manipulation of data produced by quantum chemistry calculations. It is designed with the goal of providing a reliable and efficient method of storing and exchanging wave function parameters and matrix elements, making it an important tool for researchers in the field of quantum chemistry. In this work, we present an overview of the TREXIO file format and library.

Density Matrix Renormalization Group for Transcorrelated Hamiltonians: Ground and Excited States in Molecules.

We present the theory of a density matrix renormalization group (DMRG) algorithm which can solve for both the ground and excited states of non-Hermitian transcorrelated Hamiltonians and show applications in molecular systems. Transcorrelation (TC) accelerates the basis set convergence rate by including known physics (such as, but not limited to, the electron-electron cusp) in the Jastrow factor used for the similarity transformation. It also improves the accuracy of approximate methods such as coupled cluster singles and doubles (CCSD) as shown by recent studies.

Ethylene Dimerization and Oligomerization Using Bis(phosphino)boryl Supported Ni Complexes.

We report the dimerization and oligomerization of ethylene using bis(phosphino)boryl supported Ni(II) complexes as catalyst precursors. By using alkylaluminum(III) compounds or other Lewis acid additives, Ni(II) complexes of the type (PBP)NiBr (R = Bu or Ph) show activity for the production of butenes and higher olefins. Optimized turnover frequencies of 640 mol·mol·s for the formation of butenes with 41(1)% selectivity for 1-butene using (PBP)NiBr, and 68 mol·mol·s for butenes production with 87.

σ-GeH and Germyl Cationic Pt(II) Complexes.

The low electron count Pt(II) complexes [Pt(NHC')(NHC)][BAr] (where NHC is a -heterocyclic carbene ligand and NHC' its metalated form) react with tertiary hydrogermanes HGeR at room temperature to generate the 14-electron platinum(II) germyl derivatives [Pt(GeR)(NHC)][BAr]. Low-temperature NMR studies allowed us to detect and characterize spectroscopically some of the σ-GeH intermediates [Pt(η-HGeR)(NHC')(NHC)][BAr] that evolve into the platinum-germyl species. One of these compounds has been characterized by X-ray diffraction studies, and the interaction of the H-Ge bond with the platinum center has been analyzed in detail by computational methods, which suggest that the main contribution is the donation of the H-Ge to a σ*(Pt-C) orbital, but backdonation from the platinum to the σ*(Ge-H) orbital is significant.

Adherence to multidisciplinary care in a prospective chronic kidney disease cohort is associated with better outcomes.

Introduction: The Renal Healthcare Program Uruguay (NRHP-UY) is a national, multidisciplinary program that provides care to chronic kidney disease (CKD) patients. In this study, we report the global results of CKD patient outcomes and a comparison between those treated at the NRHP-UY Units, with those patients who were initially included in the program but did not adhere to follow up.

Methods: A cohort of not-on dialysis CKD patients included prospectively in the NRHP-UY between October 1st 2004 and September 30th 2017 was followed-up until September 30th 2019.

Circulating Tumor and Immune Cells for Minimally Invasive Risk Stratification of Smoldering Multiple Myeloma.

Purpose: Early intervention in smoldering multiple myeloma (SMM) requires optimal risk stratification to avoid under- and overtreatment. We hypothesized that replacing bone marrow (BM) plasma cells (PC) for circulating tumor cells (CTC), and adding immune biomarkers in peripheral blood (PB) for the identification of patients at risk of progression due to lost immune surveillance, could improve the International Myeloma Working Group 20/2/20 model.

Experimental Design: We report the outcomes of 150 patients with SMM enrolled in the iMMunocell study, in which serial assessment of tumor and immune cells in PB was performed every 6 months for a period of 3 years since enrollment.

Mineral and bone disorder and longterm survival in a chronic kidney disease grade 3b-4cohort.

Mineral and bone disorder biomarkers 'normal ranges' are controversial. The aim of the study was to evaluate the association between serum calcium (Ca), phosphate (P), intact parathyroid hormone (iPTH), and 25(OH) vitamin D levels and mortality risk, in a chronic kidney disease (CKD) grade (G) 3b-4 cohort. The Uruguayan National Renal Healthcare Program (NRHP-UY) CKD patients' cohort, included between 1 October 2004 and 1 March 2020 and followed-up until 1 March 2021, was analyzed with the Ethics Committee approval.

Bonding Situation of σ-E-H Complexes in Transition Metal and Main Group Compounds.

The ambiguous bonding situation of σ-E-H (E=Si, B) complexes in transition metal compounds has been rationalized by means of Density Functional Theory calculations. To this end, the combination of the Energy Decomposition Analysis (EDA) method and its Natural Orbital for Chemical Valance (NOCV) extension has been applied to representative complexes described in the literature where the possible η versus η coordination mode is not unambiguously defined. Our quantitative analyses, which complement previous data based on the application of the Quantum Theory of Atoms in Molecules (QTAIM) approach, indicate that there exists a continuum between genuine η and η modes depending mainly on the strength of the backdonation.

Activation of Si-H and B-H bonds by Lewis acidic transition metals and p-block elements: same, but different.

In this we discuss the ability of transition metal complexes to activate and cleave the Si-H and B-H bonds of hydrosilanes and hydroboranes (tri- and tetra-coordinated) in an electrophilic manner, avoiding the need for the metal centre to undergo two-electron processes (oxidative addition/reductive elimination). A formal polarization of E-H bonds (E = Si, B) upon their coordination to the metal centre to form σ-EH complexes (with coordination modes η or η) favors this type of bond activation that can lead to reactivities involving the formation of transient silylium and borenium/boronium cations similar to those proposed in silylation and borylation processes catalysed by boron and aluminium Lewis acids. We compare the reactivity of transition metal complexes and boron/aluminium Lewis acids through a series of catalytic reactions in which pieces of evidence suggest mechanisms involving electrophilic reaction pathways.

Robust dicopper(i) μ-boryl complexes supported by a dinucleating naphthyridine-based ligand.

Copper boryl species have been widely invoked as reactive intermediates in Cu-catalysed C-H borylation reactions, but their isolation and study have been challenging. Use of the robust dinucleating ligand DPFN (2,7-bis(fluoro-di(2-pyridyl)methyl)-1,8-naphthyridine) allowed for the isolation of two very thermally stable dicopper(i) boryl complexes, [(DPFN)Cu(μ-Bpin)][NTf] (2) and [(DPFN)Cu(μ-Bcat)][NTf] (4) (pin = 2,3-dimethylbutane-2,3-diol; cat = benzene-1,2-diol). These complexes were prepared by cleavage of the corresponding diborane reaction with the alkoxide [(DPFN)Cu(μ-O Bu)][NTf] (3).

Methodology for the identification of relevant loci for milk traits in dairy cattle, using machine learning algorithms.

Machine learning methods were considered efficient in identifying single nucleotide polymorphisms (SNP) underlying a trait of interest. This study aimed to construct predictive models using machine learning algorithms, to identify loci that best explain the variance in milk traits of dairy cattle. Further objectives involved validating the results by comparison with reported relevant regions and retrieving the pathways overrepresented by the genes flanking relevant SNPs.

Highly Efficient Synthesis of Poly(silylether)s: Access to Degradable Polymers from Renewable Resources.

The design of new materials with tunable properties and intrinsic recyclability, derived from biomass under mild conditions, stands as a gold standard in polymer chemistry. Reported herein are platinum complexes which catalyze the formation of poly(silylether)s (PSEs) at low catalyst loadings. These polymers are directly obtained from dual-functional biobased building blocks such as 5-hydroxymethylfurfural (HMF) or vanillin, coupled with various dihydrosilanes.

Ambiphilic boryl groups in a neutral Ni(ii) complex: a new activation mode of H.

The concept of metal-ligand cooperation opens new avenues for the design of catalytic systems that may offer alternative reactivity patterns to the existing ones. Investigations of this concept with ligands bearing a boron center in their skeleton established mechanistic pathways for the activation of small molecules in which the boron atom usually performs as an electrophile. Here, we show how this electrophilic behavior can be modified by the ligand to the boron center, evincing its ambiphilic nature.

Reversible carbon-boron bond formation at platinum centers through σ-BH complexes.

A reversible carbon-boron bond formation has been observed in the reaction of the coordinatively unsaturated, cyclometalated, Pt(ii) complex [Pt(I BuPr')(I BuPr)][BAr], , with tricoordinated boranes HBR. X-ray diffraction studies provided structural snapshots of the sequence of reactions involved in the process. At low temperature, we observed the initial formation of the unprecedented σ-BH complexes [Pt(HBR)(I BuPr')(I BuPr)][BAr], one of which has been isolated.

The Gene Encodes for an Atypical Dual Specificity Lipid-Like Phosphatase Expressed in Promastigotes and Amastigotes; Substrate Specificity, Intracellular Localizations, and Putative Role(s).

The intracellular protozoan parasites of the genus are responsible for Leishmaniases, vector borne diseases with a wide range of clinical manifestations. causes visceral leishmaniasis (kala azar), the most severe of these diseases. Along their biological cycle, parasites undergo distinct developmental transitions including metacyclogenesis and differentiation of metacyclic promastigotes (MPs) to amastigotes.

Bimetallics in a Nutshell: Complexes Supported by Chelating Naphthyridine-Based Ligands.

Bimetallic motifs are a structural feature common to some of the most effective and synthetically useful catalysts known, including in the active sites of many metalloenzymes and on the surfaces of industrially relevant heterogeneous materials. However, the complexity of these systems often hampers detailed studies of their fundamental properties. To glean valuable mechanistic insight into how these catalysts function, this research group has prepared a family of dinucleating 1,8-naphthyridine ligands that bind two first-row transition metals in close proximity, originally designed to help mimic the proposed active site of metal oxide surfaces.