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Clip‐off Chemistry is a synthetic strategy that our group previously developed to obtain new molecules and materials through selective cleavage of bonds. Herein, we report recent work to expand Clip‐off Chemistry by introducing into it a retrosynthetic analysis step that, based on virtual extension of the products through cleavable bonds, enables one to define the required precursor materials. As proof‐of‐concept, we have validated our new approach by synthesising and characterising four aldehyde‐functionalised Rh(II)‐based complexes: a homoleptic cluster; a cis‐disubstituted paddlewheel cluster; a macrocycle; and a crown. [ABSTRACT FROM AUTHOR]

Clip‐off Chemistry is a synthetic strategy that our group previously developed to obtain new molecules and materials through selective cleavage of bonds. Herein, we report recent work to expand Clip‐off Chemistry by introducing into it a retrosynthetic analysis step that, based on virtual extension of the products through cleavable bonds, enables one to define the required precursor materials. As proof‐of‐concept, we have validated our new approach by synthesising and characterising four aldehyde‐functionalised Rh(II)‐based complexes: a homoleptic cluster; a cis‐disubstituted paddlewheel cluster; a macrocycle; and a crown. [ABSTRACT FROM AUTHOR]

• High spatial-resolution techniques allowed the study of complex layered structures. • We characterised carnation and red colours in Romanesque mural paintings. • Visual inspection and material composition analysis match old treatises instructions. • We detected eight different pigments according Theophilus' and Hermeneia treatises. • We verified the use of the three-tone procedure in Sant Climent de Taüll paintings. Medieval texts describe the use of the three-tone system as a pictorial procedure characteristic of Romanesque art to represent shape and volume. Some Medieval art treatises provide detailed instructions of its application, using specific names for each of the carnation colours: membran a (mid-tone or base colour), rosa and posc (darker) and lumen (lighter). In this study we have verified its use and application by analysing the mural paintings of the central apse of the church of Sant Climent de Taüll (Catalonia), currently on display at the Museu Nacional d'Art de Catalunya. A combination of microanalytical techniques, micro-infrared spectroscopy (μFTIR), synchrotron-based micro-X-ray diffraction (µSR-XRD), Scanning Electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS), and Optical microscopy (OM), provided precise information on the composition and distribution of the compounds in the sequence of micrometric layers. We have identified the use of up to eight different pigments carefully mixed, to obtain a variety of tones in accordance to the recipes given in the Theophilus' De diversis Artibus and the Hermeneia (Byzantine pictorial tradition). The inner layers, painted directly on the still wet lime mortar, show the typical carbonation microstructure of fresco , while the surface layers for the contours of geometric decorative elements and figures which required longer working times, were applied al secco. [Display omitted] [ABSTRACT FROM AUTHOR]

Metal–organic frameworks (MOFs) based on high-connected nets are generally very attractive due to their combined robustness and porosity. Here, we describe the synthesis of BCN-348, a new high-connected Zr-MOF built from an 8-connected (8-c) cubic Zr-oxocluster and an 8-c organic linker. BCN-348 contains a minimal edge-transitive 3,4,8-c eps net, and combines mesoporosity with thermal and hydrolytic stability. Encouraging results from preliminary studies on its use as a catalyst for hydrolysis of a nerve-agent simulant suggest its potential as an agent for detoxification of chemical weapons and other pernicious compounds. [ABSTRACT FROM AUTHOR]

Increasing the chemical complexity of metal–organic cages (MOCs) or polyhedra (MOPs) demands control over the simultaneous organization of diverse organic linkers and metal ions into discrete caged structures. Herein, we show that a pre-assembled complex of the archetypical cuboctahedral MOP can be used as a template to replicate such caged structure, one having a "triblock Janus-type" configuration that is both heterometallic and heteroleptic. [ABSTRACT FROM AUTHOR]

The Neonatal Line (NNL) of the tooth serves as a unique identifier, allowing us to distinguish whether a child survived birth. This line is essential for assessing the age at death of infants from skeletal remains found in archaeological contexts. Our primary objective is to accurately determine the age of infant intramural inhumations from the Iberian Iron Age (8th-1st centuries BC) by analyzing histological sections of tooth germs. Due to their fragility and high susceptibility to taphonomic factors, these samples are challenging to handle. By accurately assessing their age, we aim to classify individuals into various stages of infant mortality, which will help reconstruct infant mortality patterns in these populations. We analyze unerupted and still-forming crown deciduous teeth from 45 infant burials. By calculating Crown Formation Time (CFT) and identifying the NNL, we determine both gestational and chronological ages. We further validate the reliability of NNL identification through Synchrotron X-ray Fluorescence (SXRF) elemental analysis (Ca, Zn, Cu) on two contemporary and two archaeological samples. Our histological study reveals the chronological age of 38 infants from Iberian settlements, ranging from the 30th week of gestation to the 2nd postnatal month. The age distribution shows an attritional mortality pattern, with nearly half experiencing perinatal mortality, including preterm births. These findings support the hypothesis that mortality was primarily attributed to natural causes. Our research enhances the understanding of infant life history events in prehistory by combining histological analysis of tooth NNL and CFT, highlighting the technique's potential and limitations. [ABSTRACT FROM AUTHOR]

We have synthesised and characterised the two possible isomers of heteroleptic trigonal antiprismatic M12L6L′6 MOPs by screening reactions of rhodium acetate with different pairs of complementary dicarboxylate linkers. The resulting 12 new MOPs (eight of isomer A + four of isomer B) are microporous in the solid state, exhibiting Brunauer–Emmett–Teller (BET) surface areas as high as 770 m2 g−1. [ABSTRACT FROM AUTHOR]

Human aldehyde dehydrogenase (ALDH) participates in the oxidative stress response and retinoid metabolism, being involved in several diseases, including cancer, diabetes and obesity. The ALDH1A3 isoform has recently elicited wide interest because of its potential use as a cancer stem cell biomarker and drug target. We report high-resolution three-dimensional ALDH1A3 structures for the apo-enzyme, the NAD+ complex and a binary complex with ATP. Each subunit of the ALDH1A3-ATP complex contains one ATP molecule bound to the adenosine-binding pocket of the cofactor-binding site. The ATP complex also shows a molecule, putatively identified as a polyethylene glycol aldehyde, covalently bound to the active-site cysteine. This mimics the thioacyl-enzyme catalytic intermediate, which is trapped in a dead enzyme lacking an active cofactor. At physiological concentrations, ATP inhibits the dehydrogenase activity of ALDH1A3 and other isoforms, with a Ki value of 0.48 mM for ALDH1A3, showing a mixed inhibition type against NAD+. ATP also inhibits esterase activity in a concentration-dependent manner. The current ALDH1A3 structures at higher resolution will facilitate the rational design of potent and selective inhibitors. ATP binding to ALDH1A3 enables activity modulation by the energy status of the cell and metabolic reprogramming, which may be relevant in several disease conditions. Three X-ray structures are presented of human aldehyde dehydrogenase family 1 member A3 (ALDH1A3), a potential cancer stem cell biomarker (alone, with NAD+ and with ATP) and structure determination performed using molecular replacement. [ABSTRACT FROM AUTHOR]

Bond breaking is an essential process in chemical transformations and the ability of researchers to strategically dictate which bonds in a given system will be broken translates to greater synthetic control. Here, we report extending the concept of selective bond breaking to reticular materials in a new synthetic approach that we call Clip‐off Chemistry. We show that bond‐breaking in these structures can be controlled at the molecular level; is periodic, quantitative, and selective; is effective in reactions performed in either solid or liquid phases; and can occur in a single‐crystal‐to‐single‐crystal fashion involving the entire bulk precursor sample. We validate Clip‐off Chemistry by synthesizing two topologically distinct 3D metal‐organic frameworks (MOFs) from two reported 3D MOFs, and a metal‐organic macrocycle from metal‐organic polyhedra (MOP). Clip‐off Chemistry opens the door to the programmed disassembly of reticular materials and thus to the design and synthesis of new molecules and materials. [ABSTRACT FROM AUTHOR]

Bond breaking is an essential process in chemical transformations and the ability of researchers to strategically dictate which bonds in a given system will be broken translates to greater synthetic control. Here, we report extending the concept of selective bond breaking to reticular materials in a new synthetic approach that we call Clip‐off Chemistry. We show that bond‐breaking in these structures can be controlled at the molecular level; is periodic, quantitative, and selective; is effective in reactions performed in either solid or liquid phases; and can occur in a single‐crystal‐to‐single‐crystal fashion involving the entire bulk precursor sample. We validate Clip‐off Chemistry by synthesizing two topologically distinct 3D metal‐organic frameworks (MOFs) from two reported 3D MOFs, and a metal‐organic macrocycle from metal‐organic polyhedra (MOP). Clip‐off Chemistry opens the door to the programmed disassembly of reticular materials and thus to the design and synthesis of new molecules and materials. [ABSTRACT FROM AUTHOR]

The plant‐specific class XI myosins (MyoXIs) play key roles at the molecular, cellular and tissue levels, engaging diverse adaptor proteins to transport cargoes along actin filaments. To recognize their cargoes, MyoXIs have a C‐terminal globular tail domain (GTD) that is evolutionarily related to those of class V myosins (MyoVs) from animals and fungi. Despite recent advances in understanding the functional roles played by MyoXI in plants, the structure of its GTD, and therefore the molecular determinants for cargo selectivity and recognition, remain elusive. In this study, the first crystal structure of a MyoXI GTD, that of MyoXI‐K from Arabidopsis thaliana, was elucidated at 2.35 Å resolution using a low‐identity and fragment‐based phasing approach in ARCIMBOLDO_SHREDDER. The results reveal that both the composition and the length of the α5–α6 loop are distinctive features of MyoXI‐K, providing evidence for a structural stabilizing role for this loop, which is otherwise carried out by a molecular zipper in MyoV GTDs. The crystal structure also shows that most of the characterized cargo‐binding sites in MyoVs are not conserved in plant MyoXIs, pointing to plant‐specific cargo‐recognition mechanisms. Notably, the main elements involved in the self‐regulation mechanism of MyoVs are conserved in plant MyoXIs, indicating this to be an ancient ancestral trait. [ABSTRACT FROM AUTHOR]

Use of preformed metal‐organic polyhedra (MOPs) as supermolecular building blocks (SBBs) for the synthesis of metal‐organic frameworks (MOFs) remains underexplored due to lack of robust functionalized MOPs. Herein we report the use of polycarboxylate cuboctahedral RhII‐MOPs for constructing highly‐connected MOFs. Cuboctahedral MOPs were functionalized with carboxylic acid groups on their 12 vertices or 24 edges through coordinative or covalent post‐synthetic routes, respectively. We then used each isolated polycarboxylate RhII‐MOP as 12‐c cuboctahedral or 24‐c rhombicuboctahedral SBBs that, upon linkage with metallic secondary building units (SBUs), afford bimetallic highly‐connected MOFs. The assembly of a pre‐synthesized 12‐c SBB with a 4‐c paddle‐wheel SBU, and a 24‐c SBB with a 3‐c triangular CuII SBU gave rise to bimetallic MOFs having ftw (4,12)‐c or rht (3,24)‐c topologies, respectively. [ABSTRACT FROM AUTHOR]

Use of preformed metal‐organic polyhedra (MOPs) as supermolecular building blocks (SBBs) for the synthesis of metal‐organic frameworks (MOFs) remains underexplored due to lack of robust functionalized MOPs. Herein we report the use of polycarboxylate cuboctahedral RhII‐MOPs for constructing highly‐connected MOFs. Cuboctahedral MOPs were functionalized with carboxylic acid groups on their 12 vertices or 24 edges through coordinative or covalent post‐synthetic routes, respectively. We then used each isolated polycarboxylate RhII‐MOP as 12‐c cuboctahedral or 24‐c rhombicuboctahedral SBBs that, upon linkage with metallic secondary building units (SBUs), afford bimetallic highly‐connected MOFs. The assembly of a pre‐synthesized 12‐c SBB with a 4‐c paddle‐wheel SBU, and a 24‐c SBB with a 3‐c triangular CuII SBU gave rise to bimetallic MOFs having ftw (4,12)‐c or rht (3,24)‐c topologies, respectively. [ABSTRACT FROM AUTHOR]

The addition of compounds to scavenge the radical species produced during biological small‐angle X‐ray scattering (BioSAXS) experiments is a common strategy to reduce the effects of radiation damage and produce better quality data. As almost half of the experiments leading to structures deposited in the SASBDB database used scavengers, finding potent scavengers would be advantageous for many experiments. Here, four compounds, three nucleosides and one nitrogenous base, are presented which can act as very effective radical‐scavenging additives and increase the critical dose by up to 20 times without altering the stability or reducing the contrast of the tested protein solutions. The efficacy of these scavengers is higher than those commonly used in the field to date, as verified for lysozyme solutions at various concentrations from 7.0 to 0.5 mg ml−1. The compounds are also very efficient at mitigating radiation damage to four proteins with molecular weights ranging from 7 to 240 kDa and pH values from 3 to 8, with the extreme case being catalase at 6.7 mg ml−1, with a scavenging factor exceeding 100. These scavengers can therefore be instrumental in expanding BioSAXS to low‐molecular‐weight and low‐concentration protein samples that were previously inaccessible owing to poor data quality. It is also demonstrated that an increase in the critical dose in standard BioSAXS experiments leads to an increment in the retrieved information, in particular at higher angles, and thus to higher resolution of the model. [ABSTRACT FROM AUTHOR]

Catalases are among the main scavengers of reactive oxygen species (ROS) present in the peroxisome, thereby preventing oxidative cellular and tissular damage. In human, multiple diseases are associated with malfunction of these organelles, which causes accumulation of ROS species and consequently the inefficient detoxification of cells. Despite intense research, much remains to be clarified about the precise molecular role of catalase in cellular homeostasis. Yeast peroxisomes and their peroxisomal catalases have been used as eukaryotic models for oxidative metabolism, ROS generation and detoxification, and associated pathologies. In order to provide reliable models for oxidative metabolism research, we have determined the high-resolution crystal structures of peroxisomal catalase from two important biotechnology and basic biology yeast models, Pichia pastoris and Kluyveromyces lactis. We have performed an extensive functional, biochemical and stability characterization of both enzymes in order to establish their differential activity profiles. Furthermore, we have analyzed the role of the peroxisomal catalase under study in the survival of yeast to oxidative burst challenges combining methanol, water peroxide, and sodium chloride. Interestingly, whereas catalase activity was induced 200-fold upon challenging the methylotrophic P. pastoris cells with methanol, the increase in catalase activity in the non-methylotrophic K. lactis was only moderate. The inhibitory effect of sodium azide and β-mercaptoethanol over both catalases was analyzed, establishing IC50 values for both compounds that are consistent with an elevated resistance of both enzymes toward these inhibitors. Structural comparison of these two novel catalase structures allows us to rationalize the differential susceptibility to inhibitors and oxidative bursts. The inherent worth and validity of the P. pastoris and K. lactis yeast models for oxidative damage will be strengthened by the availability of reliable structural-functional information on these enzymes, which are central to our understanding of peroxisomal response toward oxidative stress. Image 1 • Crystal structures of the peroxisomal catalases from Pichia pastoris at 2.3 Å and Kluyveromyces lactis at 1.85 Å. • Potassium and sodium ions provide structural stabilization to catalases. • NADPH is tightly bound to the catalase surface and prevents its inactivation. • Yeast catalases are remarkably tolerant to azide and 2-mercaptoethanol. • Exposure to H 2 O 2 with cations is more powerful than H 2 O 2 alone to inhibit yeast growth. [ABSTRACT FROM AUTHOR]

This article discusses various research articles published in the journal Angewandte Chemie International Edition. One research article by Jorge Albalad, Inhar Imaz, Daniel Maspoch, et al. explores the use of bond scission as a synthetic tool to design new molecules and materials. They demonstrate this concept by obtaining unprecedented Rh(II)-based architectures through the disassembly of metal-organic polyhedra. Another research article by Weijie Yang, Hai-Long Jiang, et al. focuses on incorporating Pd nanoparticles into MOFs for high selectivity in CO esterification. Yoshinari Sawama, et al. report on sulfonium salt reagents for introducing deuterated alkyl groups in drug discovery, while Alexis Bordet, Walter Leitner, et al. discuss the adaptivity of a catalyst in the hydrogenation of heteroaromatics. Lastly, Leticia González, et al. investigate the photophysics of [Ru(bpy)3]2+ and propose a kinetic model for its behavior. [Extracted from the article]

This document, published in the journal Angewandte Chemie, discusses various research articles in the field of chemistry. One article explores the use of bond scission as a synthetic tool to design new molecules and materials, showcasing the synthesis of Rh(II)-based architectures through the disassembly of metal-organic polyhedra. Another article focuses on the incorporation of Pd nanoparticles into MOFs for high selectivity in CO esterification. Additionally, there is a report on the use of sulfonium salt reagents for introducing deuterated alkyl groups in drug discovery, and a study on adaptive catalysts that can switch selectivity in hydrogenation reactions. Lastly, the document mentions a research article on the photophysics of [Ru(bpy)3]2+, highlighting the importance of rate-determining states in understanding its behavior. [Extracted from the article]

Abstract: Supramolecular nanocapsule 1⋅(BArF)8 is able to sequentially and selectively entrap recently discovered U2@C80 and unprecedented Sc2CU@C80, simply by soaking crystals of 1⋅(BArF)8 in a toluene solution of arc‐produced soot. These species, selectively and stepwise absorbed by 1⋅(BArF)8, are easily released, obtaining highly pure fractions of U2@C80 and Sc2CU@C80 in one step. Sc2CU@C80 represents the first example of a mixed metal actinide‐based endohedral metallofullerene (EMF). Remarkably, the host–guest studies revealed that 1⋅(BArF)8 is able to discriminate EMFs with the same carbon cage but with different encapsulated cluster and computational studies provide support for these observations. [ABSTRACT FROM AUTHOR]

Abstract: Supramolecular nanocapsule 1⋅(BArF)8 is able to sequentially and selectively entrap recently discovered U2@C80 and unprecedented Sc2CU@C80, simply by soaking crystals of 1⋅(BArF)8 in a toluene solution of arc‐produced soot. These species, selectively and stepwise absorbed by 1⋅(BArF)8, are easily released, obtaining highly pure fractions of U2@C80 and Sc2CU@C80 in one step. Sc2CU@C80 represents the first example of a mixed metal actinide‐based endohedral metallofullerene (EMF). Remarkably, the host–guest studies revealed that 1⋅(BArF)8 is able to discriminate EMFs with the same carbon cage but with different encapsulated cluster and computational studies provide support for these observations. [ABSTRACT FROM AUTHOR]

We describe solid-gas phase, single-crystal-to-single-crystal, postsynthetic modifications of a metal-organic framework (MOF). Using ozone, we quantitatively transformed the olefin groups of a UiO-66-type MOF into 1,2,4-trioxolane rings, which we then selectively converted into either aldehydes or carboxylic acids. [ABSTRACT FROM AUTHOR]

This chemistry is first used to synthesize two 3D metal-organic frameworks (MOFs) and a metal-organic macrocycle from precursor reticular materials. This chemistry is first used to synthesize two 3D metal-organic frameworks (MOFs) and a metal-organic macrocycle from precursor reticular materials. Cover Picture: Clip-off Chemistry: Synthesis by Programmed Disassembly of Reticular Materials (Angew. [Extracted from the article]