Catalytic dehydrocoupling of amine-boranes and amines into diaminoboranes: isolation of a Pt(II), Shimoi-type, η1-BH complex

The platinum complex [Pt(IBu′)(IBu)][BAr] is a very efficient catalyst in the synthesis of diaminoboranes through dehydrocoupling of amine-boranes and amines. Shimoi-type, η-BH complexes are key intermediates in the process.Financial support (FEDER contribution) from the MINECO (Projects CTQ2013-45011-P and CTQ2014-51912-REDC) and the Junta de Andalucía (Project FQM-2126) is gratefully acknowledged.We acknowledge support by the CSIC Open Access Publication Initiative through its Unit of Information Resources for Research (URICI).Peer Reviewe

Important Role of NH-Carbazole in Aryl Amination Reactions Catalyzed by 2‑Aminobiphenyl Palladacycles

2-Aminobiphenyl palladacycles are among the most successful precatalysts for Pd-catalyzed cross-coupling reactions, including aryl amination. However, the role of NH-carbazole, a byproduct of precatalyst activation, remains poorly understood. Herein, the mechanism of the aryl amination reactions catalyzed by a cationic 2-aminobiphenyl palladacycle supported by a terphenyl phosphine ligand, PCyp2ArXyl2 (Cyp = cyclopentyl; ArXyl2 = 2,6-bis(2,6-dimethylphenyl)phenyl), P1, has been thoroughly investigated. Combining computational and experimental studies, we found that the Pd(II) oxidative addition intermediate reacts with NH-carbazole in the presence of the base (NaOtBu) to yield a stable aryl carbazolyl Pd(II) complex. This species functions as the catalyst resting state, providing the amount of monoligated LPd(0) species required for catalysis and minimizing Pd decomposition. In the case of a reaction with aniline, an equilibrium between the carbazolyl complex and the on-cycle anilido analogue is established, which allows for a fast reaction at room temperature. In contrast, heating is required in a reaction with alkylamines, whose deprotonation involves coordination to the Pd center. A microkinetic model was built combining computational and experimental data to validate the mechanistic proposals. In conclusion, our study shows that despite the rate reduction observed in some reactions by the formation of the aryl carbazolyl Pd(II) complex, this species reduces catalyst decomposition and could be considered an alternative precatalyst in cross-coupling reactions.The authors thank MCIN/AEI/ 10.13039/501100011033 (Grant PID2020-113797R), US/JUNTA/FEDER, UE (Grant US-1262266), and FEDER/Junta de Andalucía-Consejería de Economía y Conocimiento (Grant P20_00624) for the financial support. R.J.R. and A.N. acknowledge the support from the Research Council of Norway through the Centre of Excellence (No. 262695) and A.N. for its FRINATEK program (314321). R.J.R. thanks the Universidad de Sevilla (V and VI Plan Propio de Investigación) for research fellowships. R.J.R. thanks the Norwegian Metacenter for Computational Science (NOTUR) for computational resources (No. nn4654k). Thanks are also due to Nazaret Santamaría for helping with kinetic experiments

Isocyanide insertion into Au-H bonds: first gold iminoformyl complexes

Isocyanides insert into gold(III)-hydrogen bonds to give the first examples of gold iminoformyl complexes. The reaction is initiated by catalytic amounts of radicals; DFT calculations indicate that this is an equilibrium reaction driven forward by isocyanide in sufficient excess to trap the Au(II) intermediate

Zero-valent ML2 complexes of group 10 metals supported by terphenyl phosphanes

Bulky terphenyl phosphane ligands PMe2Ar′ (Ar′ = terphenyl group) facilitate the isolation of zero-valent bis-phosphane complexes of nickel, palladium and platinum. The former show coordination numbers greater than two in the solid state due to the existence of Ni-Careneinteractions with the terphenyl fragment.Ministerio de Ciencia, Innovación y Universidades (MICINN). España Universidad de SevillaDepartamento de Química "Profesor José Carlos Vílchez Martín

Inter-laboratory comparability of the in vitro digestibility method based on the static INFOGEST method

Poster presentado en: International Symposium Dietry Protein for Human Health. Utrecht, Paises Bajos. 14-16 septiembre (2023

Luminescent Au(III)−M(I) (M = Cu, Ag) aggregates based on dicyclometalated bis(alkynyl) gold anions

The syntheses and structures of a series of complexes based on the C^C-chelated Au(III) unit (C^C = 4,4′-bis(t-butyl) 2,2′-biphenyl-1,1′-diyl) are reported, namely [{(C^C)Au(C≡CtBu)2}2M2], (C^C)Au(C≡CR)(C≡NXyl), ) and [{(C^C)Au(C≡CR)2}{M(C≡NXyl)}] (M = Ag, Cu; R = tBu, C6H4tBu-4, C6H4OMe-4; Xyl = 3,5-Me2C6H3). The X-ray structures reveal a broad range of dispositions determined by the different coordination modes of Ag(I) or Cu(I) in the different structures. The complexes are bright photoemitters in the solid state and in poly(methyl methacrylate) (PMMA) films. The photoluminescence is dominated by 3IL(C^C) transitions, with indirect effects from the rest of the molecules, as supported by theoretical calculations. This work opens up the possibility of accessing Au(III) carbon rich anions to construct photoluminescent aggregates

Clonal chromosomal mosaicism and loss of chromosome Y in elderly men increase vulnerability for SARS-CoV-2

The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, COVID-19) had an estimated overall case fatality ratio of 1.38% (pre-vaccination), being 53% higher in males and increasing exponentially with age. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, we found 133 cases (1.42%) with detectable clonal mosaicism for chromosome alterations (mCA) and 226 males (5.08%) with acquired loss of chromosome Y (LOY). Individuals with clonal mosaic events (mCA and/or LOY) showed a 54% increase in the risk of COVID-19 lethality. LOY is associated with transcriptomic biomarkers of immune dysfunction, pro-coagulation activity and cardiovascular risk. Interferon-induced genes involved in the initial immune response to SARS-CoV-2 are also down-regulated in LOY. Thus, mCA and LOY underlie at least part of the sex-biased severity and mortality of COVID-19 in aging patients. Given its potential therapeutic and prognostic relevance, evaluation of clonal mosaicism should be implemented as biomarker of COVID-19 severity in elderly people. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, individuals with clonal mosaic events (clonal mosaicism for chromosome alterations and/or loss of chromosome Y) showed an increased risk of COVID-19 lethality