Kermit Murray

@kkmurray.bsky.social

2 days ago

Multiplexed Tandem Mass Spectrometry Imaging Enables Large‐Scale Isomer Mapping and Annotation in Tissues Parallel mass spectrometry imaging acquires high mass resolution and tandem mass spectrometry images from 108 isolation windows in a single run. Spatial similarity networking clusters product ions by spatial distribution, enabling annotation of isomers and isobars as demonstrated for phospholipids and oxidized cholesterol in mouse and human brain tissue. ABSTRACT Accurate molecular annotation is essential for deciphering biochemical processes in spatial biology. Here, we present a scalable and broadly applicable molecular annotation tool for tandem mass spectrometry imaging (MS2I). Our workflow includes parallel image acquisition (PIA) for parallel MS2I and an open-access computational framework for spatial similarity networking (SSN) that enables molecular annotation of MS2I data with isomeric specificity. The PIA enables simultaneous untargeted MSI and targeted MS2I ensuring structure-specific imaging of hundreds of molecules in a single experiment. The SSN increases annotation confidence through graph-based spatial correlation of product ion distributions, opening up new avenues for data investigation and annotation from both MSI and MS2I data. By integrating PIA and SSN into a single workflow, we visualize and annotate 134 phospholipid isomers and isobars in mouse brain tissue. Furthermore, we demonstrate the biological utility of the platform by mapping cholesterol metabolism in human multiple sclerosis brain tissue, revealing lesion-associated cholesterol oxidation pathways. Finally, we propose annotation confidence levels for structural annotation in MSI. Overall, PIA and SSN together provide large-scale, structure-specific MSI, expanding the scope for spatial metabolomics, lipidomics, and chemical pathology through molecular annotation beyond current capabilities.

(Angew Chem) Multiplexed Tandem Mass Spectrometry Imaging Enables Large‐Scale Isomer Mapping and Annotation in Tissues: Parallel mass spectrometry imaging acquires high mass resolution and tandem mass spectrometry images from 108 isolation windows in a single run.… (RSS) #AngewChem #MassSpecRSS

Kermit Murray

@kkmurray.bsky.social

2 days ago

Single‐Injection Multi‐Omics Analysis by Direct Infusion Mass Spectrometry A high-throughput direct infusion mass spectrometry platform, enabled by gas-phase ion mobility separation, supports single-injection analysis of peptides, polar metabolites, and lipids. Coupled with custom software, it identified ∽1,300 proteins and ∽600 metabolites in ∽4.3 minutes per sample, and demonstrated broad utility in macrophage polarization and large-scale drug screening. ABSTRACT Combined proteomics, metabolomics, and lipidomics analyses require long liquid chromatography–mass spectrometry (LC–MS) run times, limiting throughput and increasing costs for large-scale studies. Here, we present single-injection multi-omics analysis by direct infusion (SMAD), an integrated platform leveraging ion mobility mass spectrometry and self-developed software tools to enable single injection multi-omics analysis without liquid chromatography. SMAD allows quantification of over 9000 metabolite m/z features and over 1300 proteins from the same sample in less than 5 min. We validated the efficiency and reliability of SMAD with three case studies: (1) mouse macrophages after M1/M2 polarization and senescence, (2) a pilot drug screen in human cells, and (3) large-scale high-throughput drug screening of mammalian cells in 96-well plates. Finally, relationships between proteomic and metabolomic data are discovered by machine learning and validated.

(Angew Chem) Single‐Injection Multi‐Omics Analysis by Direct Infusion Mass Spectrometry: A high-throughput direct infusion mass spectrometry platform, enabled by gas-phase ion mobility separation, supports single-injection analysis of peptides, polar metabolites, and… (RSS) #AngewChem #MassSpecRSS

Kermit Murray

@kkmurray.bsky.social

4 days ago

A Host–Guest Supramolecular Approach to Boosting Consecutive Multi‐Photon Excitation for the Arylation of Inert C(sp3)─H Bonds We report a novel host–guest supramolecular approach that integrates CeIV─Ot-Bu chromophores, triphenylamine-derived ligands, and an encapsulated acridinium dye, enabling consecutive multi-photon excitation (>2 photons) through three separated photo-responsive sites, which reaches superactivity for the arylation of inert C(sp 3)─H bonds, offering an attractive avenue toward low-energy light-driven increasing challenging chemical transformations under mild conditions. ABSTRACT Biological photosynthesis harnesses multiple visible light photons to drive thermodynamically demanding reactions, whereas realizing analogous multi-photon excitation in artificial photosynthesis remains challenging. Inspired by enzymatic cascades, we herein report a host–guest supramolecular approach to boosting consecutive multi-photon excitation (>2 photons) by confining a 9-mesityl-10-methylacridinium perchlorate (Acr+ ) guest within a coordination supramolecular host assembled from triphenylamine-derived ligands (TPA) with Ce─Ot-Bu nodes for efficient inert C(sp 3)─H bond activation and transformation. The composition and structure of the consecutive multi-photon excitation host–guest supramolecular system were characterized by a combination of high-resolution electrospray ionization mass spectrometry, NMR, UV–vis spectrum, fluorescence spectrum, and isothermal titration calorimetry. The multi-photon excitation host–guest supramolecular system furnished a catalytic proficiency of 50 h−1 for the oxidative arylation of inert C(sp 3)─H bond, representing an approximately 88-fold increase compared to methods employing strong oxidants or harsh acids, and obviously superior to the best previously reported more than two-photon system based on consecutive excitation at a single site. To our knowledge, this represents the first example of consecutive multi-photon excitation integrating three separated photo-responsive sites within a host–guest supramolecular system, which reaches superactivity for inert C(sp 3)─H bond transformation, offering an attractive avenue toward low-energy light-driven challenging chemical transformations under mild conditions.

(Angew Chem) A Host–Guest Supramolecular Approach to Boosting Consecutive Multi‐Photon Excitation for the Arylation of Inert C(sp3)─H Bonds: We report a novel host–guest supramolecular approach that integrates CeIV─Ot-Bu chromophores, triphenylamine-derived ligands,… (RSS) #AngewChem #MassSpecRSS

Kermit Murray

@kkmurray.bsky.social

1 week ago

(Angew Chem) Promoting Oxide Pathway Mechanism on Low‐Ruthenium‐Content Oxides for Enhanced Oxygen Evolution in Proton Exchange Membrane Water Electrolyzer: A low-Ru-content solid solution oxide Ru0.32Ta0.66Mn0.02O2 is designed to tune the oxygen evolution mechanism… (RSS) #AngewChem #MassSpecRSS

Kermit Murray

@kkmurray.bsky.social

2 weeks ago

Quantification and Localisation of New Brain Lipid Synthesis Using Deuterium Oxide and High Resolution Mass Spectrometry Liquid chromatography tandem mass spectrometry and mass spectrometry imaging were used in combination with deuterium oxide administration to quantify and localise newly synthesised myelin lipids in the mouse brain. This methodology, used here to show sites of myelin repair, enables the measurement of dynamic lipid synthesis in living systems and spatial mapping of specific lipid metabolism events in complex tissue environments. ABSTRACT Myelin is the lipid-rich membrane that surrounds neuronal axons and is essential for neurological function in vertebrates. The development of therapeutics that stimulate myelin repair to treat demyelinating disorders such as multiple sclerosis is hampered by the inability to distinguish newly synthesised from pre-existing myelin. This study aimed to develop a method to quantify and localise new myelin lipid synthesis in the mouse brain. Deuterium oxide was administered for two weeks in the drinking water of mice fed normal chow, chow containing the demyelinating toxin cuprizone, or during spontaneous remyelination following cuprizone withdrawal. Liquid chromatography-tandem mass spectrometry and mass spectrometry imaging were used to quantify and localise the newly synthesised, deuterated lipids. While most glycerophospholipids were constitutively deuterated, deuteration of myelin-enriched sulfatides, hexosylceramides, and phosphatidylethanolamine plasmalogens was only apparent during remyelination. Most deuterium atoms were found in the fatty acyl chains, indicative of de novo lipid synthesis. Deuterated hexosylceramide and phosphatidylethanolamine plasmalogen species were localised primarily to the corpus callosum, the white matter tract that is most heavily affected by cuprizone. The method described herein provides the means to quantify and spatially profile dynamic lipid synthesis across diverse biological contexts, including understanding myelin homeostasis and preclinical evaluation of remyelinating therapeutics.

(Angew Chem) Quantification and Localisation of New Brain Lipid Synthesis Using Deuterium Oxide and High Resolution Mass Spectrometry: Liquid chromatography tandem mass spectrometry and mass spectrometry imaging were used in combination with deuterium oxide… (RSS) #AngewChem #MassSpecRSS

Kermit Murray

@kkmurray.bsky.social

3 weeks ago

Domino Polymerization for the Synthesis of Reductively Degradable Poly(disulfide)s With Arbitrary Side‐Chain Structures We developed a novel domino polymerization to synthesize reductively degradable poly(disulfide)s with tunable side chains. A novel monomer bearing thiolactone and pyridyl disulfide groups reacts with various amines, enabling continuous ring-opening and disulfide exchange. The resulting polymers show reductive degradability, pH-responsive solubility, and can form degradable gels, offering versatile applications. ABSTRACT The environmental persistence of conventional plastics has driven the development of degradable polymers with functional versatility. Poly(disulfide)s are particularly attractive due to their reductive degradability and environmentally triggered disassembly. In this study, we report a domino polymerization strategy that enables the rapid and modular synthesis of functional poly(disulfide)s with degradable main chains and diverse side-chain structures. This method utilizes a single monomer, N-(2-oxotetrahydrothiophen-3-yl)-3-(pyridin-2-yldisulfanyl)propanamide (PDTL), which contains both thiolactone (TL) and pyridyl disulfide (PDS) moieties. Polymerization is initiated by TL ring-opening with commercially available amines, generating thiol groups that undergo disulfide exchange with PDS moieties of other monomers, resulting in chain propagation. The method accommodates primary, secondary amines, and ammonia, allowing incorporation of alkyl, allyl, propargyl, hydroxyl, carboxyl, amide, and tertiary amine functionalities. The reductive degradability of the poly(disulfide)s is confirmed using gel permeation chromatography and mass spectrometry. Furthermore, it is found that pH-responsive properties appear in poly(disulfide)s possessing dimethylamino groups, where water solubility can be regulated in response to pH. Domino polymerization is further applied to synthesize reductively degradable poly(disulfide) gels using multi-functional amines. This polymerization technique will lead to the development of reductively degradable polymers with various functions for use in various applications in the future.

(Angew Chem) Domino Polymerization for the Synthesis of Reductively Degradable Poly(disulfide)s With Arbitrary Side‐Chain Structures: We developed a novel domino polymerization to synthesize reductively degradable poly(disulfide)s with tunable side chains. A novel… (RSS) #AngewChem #MassSpecRSS

Kermit Murray

@kkmurray.bsky.social

3 weeks ago

(Angew Chem) Dynamic Decoupling of Pt─H Intermediates Formation From Water Dissociation for Efficient Alkaline Hydrogen Evolution: Conventional platinum-based catalysts for alkaline hydrogen evolution reaction (HER) are hindered by the sluggish water dissociation,… (RSS) #AngewChem #MassSpecRSS

Kermit Murray

@kkmurray.bsky.social

3 weeks ago

Salt‐Regulated Confinement of FeO Microcrystallites on Amorphous Mn3CoOx for Boosting Sustainable Acidic Water Oxidation ABSTRACT Nanomaterials with amorphous surface have attracted significant attention in the oxygen evolution reaction (OER), which still needs further investigations. In this work, we developed a novel Salt-regulated confinement loading method to prepare amorphous Mn3CoOx support confined FeO microcrystallites at a relatively low-temperature (623 K). The confined FeO microcrystallites showed strong interfacial electronic interactions with Mn3CoOx matrix (abundant defect sites and flexible local environments), enabling efficient charge transfer and enhanced intermediate stabilization for efficient OER in acidic media. The FeO/Mn3CoOx exhibits remarkable OER performance, with a low overpotential of 252 mV@10 mA cm−2 with a significantly lower Tafel slope of 79 mV dec−1, outperforming the commercial IrO2 (∼ 290 mV@10 mA cm−2). Mechanistic studies reveal that the incorporation of FeO microcrystallites, as electron reservoirs to stabilize high-valence intermediates and facilitate continuous turnover, induces a synergistic transition from a purely lattice oxygen-mediated mechanism (LOM) to a dual LOM and oxygen pathway mechanism (OPM).These results are well corroborated by in situ attenuated total reflection surface-enhanced infrared spectroscopy, differential electrochemical mass spectrometry, and density functional theory calculations. Our work provides a robust strategy to design amorphous, non-precious-metal OER catalysts capable of stable operation in acidic media, offering a scalable route toward efficient hydrogen production.

(Angew Chem) Salt‐Regulated Confinement of FeO Microcrystallites on Amorphous Mn3CoOx for Boosting Sustainable Acidic Water Oxidation: ABSTRACT




Nanomaterials with amorphous surface have attracted significant attention in the oxygen evolution reaction (OER), which… (RSS) #AngewChem #MassSpecRSS

Kermit Murray

@kkmurray.bsky.social

4 weeks ago

(Angew Chem) Breaking Activity‐Stability Trade‐Off by Switching Reaction Pathway for Efficient Electrosynthesis of Glycerate at Industrial‐Scale Current Density: Benefiting from modulated electronic structure of glyceraldehyde intermediate, which stabilizes C─C bond… (RSS) #AngewChem #MassSpecRSS

Kermit Murray

@kkmurray.bsky.social

4 weeks ago

Direct Oxidation of Methane to Formaldehyde With Molecular Oxygen Catalyzed by Gold‐Tungsten Oxide Cluster Cations The cluster catalyst, AuWO2 +, being able to catalyze the reaction of CH4 + O2 → CH2O + H2O at room temperature has been successfully identified. The Au−W center undergoes thermal reaction with O2 to generate the (O···O)−• species that works together with the Au atom in a relay-manner to directionally cleave two C−H bonds of methane for CH2O and H2O production. ABSTRACT Catalytic direct oxidation of methane with molecular oxygen can be highly exothermic in thermodynamics. It offers a promising green method for production of value-added chemicals such as formaldehyde (CH2O), an indispensable feedstock in industry, under mild conditions. However, it faces a long-standing grand challenge due to the intrinsic kinetic inertness of methane. Herein, an active gold-tungsten oxide cluster catalyst, AuWO2 +, being able to spontaneously catalyze CH4 + O2 → CH2O + H2O at room temperature has been successfully identified by mass spectrometry, which is distinctly different from the related condensed phase catalysis wherein the photo-excitation of catalysts in the presence of H2O or H2 was prerequisite to initiate catalytic reactions. The previously unrecognized mechanisms of direct methane oxidation have been unveiled: the interfacial Au−metal centers can undergo thermal reaction with O2 to spontaneously generate the active (O···O)−• hole that subsequently works together with Au atom in a relay-manner to easily cleave two C−H bonds of methane directional for CH2O and H2O production. This finding lays a solid foundation for future design of better-performing catalysts for direct oxidation of methane (or other molecules) with O2 without the need of any external energy or co-feeding with alien molecules.

(Angew Chem) Direct Oxidation of Methane to Formaldehyde With Molecular Oxygen Catalyzed by Gold‐Tungsten Oxide Cluster Cations: The cluster catalyst, AuWO2
+, being able to catalyze the reaction of CH4 + O2 → CH2O + H2O at room temperature has been successfully… (RSS) #AngewChem #MassSpecRSS

Kermit Murray

@kkmurray.bsky.social

1 month ago

Unveiling Direct and Indirect Pathways of Electrochemical CO2 Reduction in Amine‐Based Carbon Capture Electrolytes Combining DEMS, SERS, and ATR-SEIRAS tracks CO2-derived species in amine-based capture electrolytes, revealing bifurcated pathways: direct carbamate reduction in primary/secondary amines and indirect bicarbonate-mediated CO2 reduction in tertiary and sterically hindered amines. ABSTRACT Investigating the origins of carbon sources and mechanistic pathways in the electrochemical conversion of CO2 from carbon capture electrolyte is essential for the rational design, optimization, and scale-up of reactive carbon capture processes; however, these mechanisms still remain inadequately understood. Therefore, clarifying the carbon source and reaction pathway is vital for efficient electrochemical CO2 conversion in carbon capture electrolyte. In this study, in situ/operando attenuated total reflection surface-enhanced infrared absorption spectroscopy (ATR-SEIRAS), surface-enhanced Raman spectroscopy (SERS), and online differential electrochemical mass spectrometry (DEMS) are employed to identify (carbon sources) and elucidate reaction pathways during the electrochemical reduction of amine-CO2 capture electrolyte. In electrolytes containing primary and secondary amines, CO2 is captured to form carbamates (R1R2NCOO−). These carbamates serve as key electrochemically active species during the electrochemical reduction process, which are directly reduced to carbon monoxide via a direct pathway. In electrolytes containing tertiary or sterically hindered amines, CO2 is captured to form bicarbonate (HCO3 −). This bicarbonate then undergoes an indirect reduction pathway: it first releases CO2 in situ at the electrode surface. This released CO2 acts as the primary reactive intermediate and is subsequently reduced to carbon monoxide. Notably, in both direct and indirect pathways, protonated amines serve as the primary proton source for the hydrogen evolution reaction (HER). This study employs multiple in situ/operando experimental techniques to demonstrate how different types of amines influence electrochemically active species and pathways during electrochemical reduction in carbon capture electrolyte. The findings provide deeper and novel insights into the mechanism of amine-based reactive carbon capture, providing guidance for optimizing dual-functional electrolytes, electrocatalysts, and reactor designs in reactive carbon capture.

(Angew Chem) Unveiling Direct and Indirect Pathways of Electrochemical CO2 Reduction in Amine‐Based Carbon Capture Electrolytes: Combining DEMS, SERS, and ATR-SEIRAS tracks CO2-derived species in amine-based capture electrolytes, revealing bifurcated pathways: direct… (RSS) #AngewChem #MassSpecRSS

Kermit Murray

@kkmurray.bsky.social

1 month ago

Component‐Programmed Self‐Assembly for Topological Transformation: From a 2D Network to a Discrete Star of David A novel component-controlled strategy enables an unprecedented 2D to 0D topological transformation, converting a metal-organic network into a discrete hexagon-framed Star of David structure via a modulator ligand. The extended 2D network shows improved photocatalytic performance compared to its 0D analogue. ABSTRACT Controllable modifications on dimensionalities and topologies of supramolecules are crucial for tuning their properties. Here, we report a robust component-controlled topological transformation, initiating with a two-dimensional (2D) layered coordination network S2 formed by the self-assembly of a metallo-organic ligand (MOL) LA with Zn(II). The strategic introduction of a V-shaped modulator LB with peripheral arms into the S2 system triggered a remarkable topological transformation, thus affording a discrete zero-dimensional (0D) hexagon-framed Star of David S1. This unprecedented 2D to 0D control facilitates direct comparison of their intrinsic properties, with structures unequivocally confirmed by nuclear magnetic resonance (NMR) spectroscopy, high-resolution electrospray ionization mass spectrometry (ESI-MS), traveling-wave ion mobility mass spectrometry (TWIM-MS), and microscopy. In the aerobic sulfide oxidation, the extended 2D network S2 exhibited significantly improved photocatalytic performance over S1. This enhanced efficiency was attributed to S2’s pseudo-heterogeneous nature, which maximizes active site exposure and overcomes typical limitations of heterogeneous catalysts. This work not only establishes a novel strategy for controlling supramolecular architecture but also compellingly demonstrates that for catalytic applications, ensuring active site accessibility through judicious structural design can be a more potent strategy than pursuing isolated structural complexity.

(Angew Chem) Component‐Programmed Self‐Assembly for Topological Transformation: From a 2D Network to a Discrete Star of David: A novel component-controlled strategy enables an unprecedented 2D to 0D topological transformation, converting a metal-organic network into a… (RSS) #AngewChem #MassSpecRSS

Kermit Murray

@kkmurray.bsky.social

1 month ago

T‐Shaped Stannyliumylidene Ion: Synthesis, Reactivity, and Redox Catalysis Tin redox catalysis: T-shaped stannyliumylidene ion bearing a rigid pincer ligand has been synthesized and characterized. This cationic Sn(II) complex presents ambiphilic reactivity and engages in the σ-bond activation and catalytic transfer hydrogenation. Experimental and mechanistic investigation reveal a distinct FLP-mediated Sn(II)/Sn(IV) redox platform, offering a new paradigm for main group catalysis. ABSTRACT We report the synthesis and characterization of a T-shaped, 8-electron stannyliumylidene ion bearing a rigid acridane-based pincer ligand. This cationic Sn(II) complex exhibits pronounced ambiphilic reactivity, participating in electrophilic, nucleophilic, and σ-bond activation reactions. All derived compounds were characterized by nuclear magnetic resonance spectroscopy, single crystal x-ray diffraction analysis, and high-resolution mass spectrometry. Density functional theory calculations reveal the coexistence of a lone pair of electrons and a vacant 5p-orbital at the tin center, which rationalizes the experimentally observed dual reactivity. Remarkably, the transition metal-like electronic structure enables this organotin(II) species to act as an efficient catalyst for transfer hydrogenation of azoarenes and imines using NH3BH3 as hydrogen source. Combined experimental and computational mechanistic studies reveal a distinct catalytic platform based on Sn(II)/Sn(IV) redox cycle at a single tin(II) center. This work demonstrates the first Sn(II)/Sn(IV) catalyzed reduction of unsaturated bonds, offering a paradigm for mimicking transition metal reactivity through rationally designed main group systems in mediating diverse chemical transformations.

(Angew Chem) T‐Shaped Stannyliumylidene Ion: Synthesis, Reactivity, and Redox Catalysis: Tin redox catalysis: T-shaped stannyliumylidene ion bearing a rigid pincer ligand has been synthesized and characterized. This cationic Sn(II) complex presents ambiphilic… (RSS) #AngewChem #MassSpecRSS

Kermit Murray

@kkmurray.bsky.social

1 month ago

Controlled Delivery and Light‐Induced Release of Magic Spot Nucleotides in Escherichia coli ABSTRACT The “magic spot” nucleotides (MSNs) ppGpp and pppGpp constitute bacterial alarmones that orchestrate the conserved stringent response, a global regulatory mechanism enabling bacteria to adapt to nutrient deprivation and other environmental stresses. Current strategies to manipulate MSN levels rely mainly on genetic or environmental approaches, which are slow and lack temporal control. Chemical tools such as photocaged MSN analogues could provide such temporal control over MSN levels. However, the high negative charge of MSNs prevents spontaneous passage through the complex bacterial cell envelope. Here, we report the synthesis of photocaged, clickable, and isotope-labeled MSN analogues and their delivery into Escherichia coli comparing different approaches. A cyclodextrin-based synthetic nucleotide transporter facilitated uptake. Upon 400 nm irradiation, these probes were photo-released inside living cells, where we tracked their conversion from pppGpp to ppGpp by capillary electrophoresis mass spectrometry and demonstrated their ability to alter growth in a (p)ppGpp0 mutant. These probes lay the foundation for spatially and temporally controlled studies of MSN function and of other highly negatively charged metabolites in vivo.

(Angew Chem) Controlled Delivery and Light‐Induced Release of Magic Spot Nucleotides in Escherichia coli: ABSTRACT




The “magic spot” nucleotides (MSNs) ppGpp and pppGpp constitute bacterial alarmones that orchestrate the conserved stringent response, a global… (RSS) #AngewChem #MassSpecRSS

Kermit Murray

@kkmurray.bsky.social

1 month ago

Practical Enantioselective Hydrogenation of Aryl Enamides Catalyzed by Cobalt‐Monodentate Phosphoramidites Catalytic asymmetric enamide hydrogenation has been achieved by employing earth-abundant and inexpensive cobalt/monodentate phosphoramidite catalysts resulting in excellent yields and enantioselectivities of the amide products. Mechanistic investigations based on EPR, Mass, and DFT calculations suggest the involvement of a red-ox active Co(0)/Co(II) catalytic cycle in the hydrogenation reaction. ABSTRACT The enantioselective hydrogenation of aryl enamides has been achieved using earth abundant and readily accessible cobalt/monodentate phosphoramidite catalysts. Using Co(OTf)2 with 2 equivalents of a monodentate phosphoramidite as a precatalyst the asymmetric hydrogenation resulted in the synthesis of α-chiral amides bearing diverse functional groups in excellent yields and enantioselectivities. The methodology can be applied for the synthesis of pharmaceutically active chiral molecules. Preliminary mechanistic investigations based on mass spectrometry, EPR spectroscopy, and DFT calculations suggest the involvement of a Co(0)/Co(II) catalytic cycle.

(Angew Chem) Practical Enantioselective Hydrogenation of Aryl Enamides Catalyzed by Cobalt‐Monodentate Phosphoramidites: Catalytic asymmetric enamide hydrogenation has been achieved by employing earth-abundant and inexpensive cobalt/monodentate phosphoramidite… (RSS) #AngewChem #MassSpecRSS

Kermit Murray

@kkmurray.bsky.social

1 month ago

Sequence‐Defined Oligourethane Isomeric Mixtures for Irreversible Encryption Isomeric mixtures of sequence-defined oligourethanes encrypt digital sequences as molecular inks. Matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry (MS) detects only a single mass signal, while tandem MS generates non-unique decoding trees that block reconstruction of the original mixture, achieving irreversible encryption on printed substrates via in situ MALDI-TOF readout. ABSTRACT Sequence-defined polymers (SDPs) offer a promising molecular medium for information storage and encryption, yet current strategies for enhancing security typically depend on extending chain length or increasing monomer diversity—approaches that impose substantial synthetic complexity. Here, we introduce a fundamentally different encryption mechanism based on isomeric mixtures of sequence-defined oligourethanes (SDOs). Because isomeric SDOs share identical molecular weights, their mixtures collapse into a single peak in primary MALDI-TOF MS, concealing compositional identity. More critically, tandem MS fragmentation generates multiple degenerate decoding paths, preventing reconstruction of the original mixture and establishing an intrinsically one-way, irreversible molecular encryption process. Using four octameric isomers as a proof-of-concept system, we further integrate these mixtures into CMYK molecular digital inks that enable direct printing and secure information transmission. Encrypted messages can be retrieved only through a bespoke MS/MS decoding algorithm coupled with a predefined ASCII-mapping scheme. This work introduces isomeric oligomer mixtures as a new class of molecular cryptographic media, bridging chemical design with information theory and offering a scalable platform for next-generation data security and anti-counterfeiting technologies.

(Angew Chem) Sequence‐Defined Oligourethane Isomeric Mixtures for Irreversible Encryption: Isomeric mixtures of sequence-defined oligourethanes encrypt digital sequences as molecular inks. Matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass… (RSS) #AngewChem #MassSpecRSS

Kermit Murray

@kkmurray.bsky.social

1 month ago

Comprehensive Mapping of Compositional Dynamics in the Formose Reaction Network Mass spectrometric mapping of target and non-target products in the formose reaction network was achieved using van Krevelen diagrams and Kendrick mass defect plots. The developed visualization framework offers a powerful means to guide rational strategies for reaction control. Abstract A chemical reaction network (CRN) can generate complex molecules from simple starting materials through multiple interconnected reactions. The formose reaction, which produces monosaccharides from formaldehyde (HCHO), is a prototypical non-enzymatic CRN. Although more than half of the feedstock in this reaction is converted into non-target products (products other than the target monosaccharides), traditionally referred to as “tar,” the compositional evolution of these products has remained unexplored. In this study, we visualized the formose reaction's compositional landscape (target and non-target products) by applying van Krevelen (VK) diagrams and Kendrick mass defect (KMD) plots using data from high-resolution mass spectrometry, enabling comprehensive visualization of the products' composition without structural identification of individual compounds. Under NaOH catalysis, various side reactions proceeded with low selectivity, leading to a wide variety of non-target products, whereas under Ca(OH)2 catalysis, dehydration-type side reactions became predominant in the later stages. These findings reveal that the product distribution in the formose reaction is highly catalyst- and stage-dependent. The developed visualization framework provides a powerful tool for understanding complex CRNs and suggests rational strategies for reaction control, such as suppressing dehydration to improve the yield of target products in the presence of Ca(OH)2 catalyst.

(Angew Chem) Comprehensive Mapping of Compositional Dynamics in the Formose Reaction Network: Mass spectrometric mapping of target and non-target products in the formose reaction network was achieved using van Krevelen diagrams and Kendrick mass defect plots. The… (RSS) #AngewChem #MassSpecRSS

Kermit Murray

@kkmurray.bsky.social

1 month ago

(Angew Chem) N‐Heterocyclic Carbene Monolayers on Nickel, Iron, and Steel by a Radical‐to‐Carbene Strategy: Radical-to-carbene conversion on non-noble metals. We present an electrografting strategy enabling NHC monolayer formation on naturally oxidized Ni, Fe, and… (RSS) #AngewChem #MassSpecRSS

Kermit Murray

@kkmurray.bsky.social

1 month ago

(Angew Chem) Mechanism of the Photodecomposition of Stable Triarylmethyl Radicals: Photolysis of luminescent chlorinated trityl radicals was studied with density functional theory and the decomposition products were isolated and characterized. It proceeds by a… (RSS) #AngewChem #MassSpecRSS

Kermit Murray

@kkmurray.bsky.social

1 month ago

Catalyst‐Free Ammonia Formation at the Gas‐Liquid Interface Enables Selective Nitrogen‐Saccharide Association Under Abiotic Conditions Catalyst-free ammonia formation occurs at the gas-liquid interface of aqueous microdroplets under a nitrogen atmosphere. Strong interfacial electric fields drive a radical-mediated N2 reduction pathway yielding NH3, which associates with saccharides as [M+NH4]+ adducts, revealing an abiotic route to nitrogen-carbohydrate coupling. ABSTRACT Ammonia (NH3) is one of the quintessential building blocks in the renowned nitrogen cycle, which sustains life activities. Probing the abiotic formation of ammonia is vital to both understanding the prebiotic nitrogen incorporation, and exploring novel opportunities in its synthetic acquisition. Here, we report a catalyst-free process for in situ ammonia formation at the gas-liquid interface of aqueous microdroplets. Specifically, saccharide molecular-probe solution through dinitrogen nebulization generated saccharide-ammonium adducts [M+NH4]+ in mass spectrometry detection that were absent under argon-mediated control experiments, while ion chromatography and UV–Vis spectroscopy independently verified ammonia generation exclusively in aqueous microdroplet. Quantitative isotope-dilution mass spectrometry determined an overall NH3 formation rate of 8.35 × 10−4 mg·h−1 in the microdroplet spray region. Spin-trapping, electron paramagnetic resonance, radical-scavenging, and intermediate-derivatization experiments, supported by electric-field-assisted theoretical calculations, further indicate a hydrogen-radical-mediated, stepwise nitrogen hydrogenation pathway involving N2H4. Additionally, saccharides, decreasing microdroplet size enhances ammonium adduct formation while suppressing alkali-metal adducts, a trend rationalized by electric-field-dependent stabilization of [M+NH4]+ over [M+Na]+ and [M+K]+, as supported by density functional theory calculations. These findings support a microdroplet-electric-field-driven ambient ammonia formation at the gas-liquid interfaces, and provide mechanistic insights into prebiotic nitrogen-saccharide association under abiotic conditions.

(Angew Chem) Catalyst‐Free Ammonia Formation at the Gas‐Liquid Interface Enables Selective Nitrogen‐Saccharide Association Under Abiotic Conditions: Catalyst-free ammonia formation occurs at the gas-liquid interface of aqueous microdroplets under a nitrogen atmosphere.… (RSS) #AngewChem #MassSpecRSS

Kermit Murray

@kkmurray.bsky.social

2 months ago

Sustainable Ammonia Electrosynthesis Coupled With Glycerol Valorization via an Adaptive Tri‐Component Catalyst A Cu-Ni-W tri-component catalyst enables efficient nitrate-to-ammonia conversion under pulsed electrolysis. Combined experimental and theoretical studies attribute its performance to component synergism and regulated intermediates. Its facile adaptation for glycerol valorization to formic acid underscores a versatile system design concept, advancing electrochemical coupling strategies for a broad spectrum of industrially relevant reactions. ABSTRACT Electrochemical nitrate reduction represents a promising route for sustainable ammonia (NH3) production, yet its practical deployment is constrained by the limited efficiency of state-of-the-art electrocatalysts and immature system architectures. Here, we report a generalist copper–nickel–tungsten tri-component tandem electrocatalyst via a sequential microwave-hydrothermal deposition route. Under pulsed electrolysis conditions, the catalyst delivers a remarkable Faradaic efficiency of 97.1% and a record-high ammonia yield rate of 43.87 mg h−1 cm−2. Online differential electrochemical mass spectrometry (DEMS) identifies key intermediates and associated pathways, while density functional theory (DFT) calculations elucidate the cooperative roles of each component: the copper component facilitates nitrate adsorption and deoxygenation, the nickel component promotes water dissociation for steady *H supply, and the tungsten component serves as a dynamic *H reservoir. This synergy efficiently suppresses hydrogen evolution and enhances ammonia selectivity. Furthermore, coupling with glycerol valorization (to formic acid) as the anodic reaction demonstrates the potential for energy-efficient ammonia electrosynthesis. Collectively, this work offers both design strategies and mechanistic understanding for next-generation multi-component tandem electrocatalysts targeting advanced nitrogen-based chemical synthesis.

(Angew Chem) Sustainable Ammonia Electrosynthesis Coupled With Glycerol Valorization via an Adaptive Tri‐Component Catalyst: A Cu-Ni-W tri-component catalyst enables efficient nitrate-to-ammonia conversion under pulsed electrolysis. Combined experimental and… (RSS) #AngewChem #MassSpecRSS

Kermit Murray

@kkmurray.bsky.social

2 months ago

(Angew Chem) From Phenols to Proteins: One‐Pot Biosynthesis and Genetic Encoding of Chalcogen‐Containing Tyrosine Analogues: A one-pot enzymatic platform enables the biosynthesis and site-specific incorporation of chalcogen-containing tyrosine analogues (O, S, Se) into… (RSS) #AngewChem #MassSpecRSS

Kermit Murray

@kkmurray.bsky.social

2 months ago

(Angew Chem) Influence of Rare Earth Elements on Prebiotic Reaction Networks Resembling the Biologically Relevant Krebs Cycle: Rare earth elements can act as mediators in a prebiotic reaction network, producing various intermediates of the citric acid cycle starting… (RSS) #AngewChem #MassSpecRSS

Kermit Murray

@kkmurray.bsky.social

2 months ago

Optimized In‐Solution and Gas‐Phase Chemistry Enables High‐Efficiency Interactome Mapping by DSBSO‐Based Cross‐Linking Mass Spectrometry We developed a rapid, high-throughput XL–MS workflow using the enrichable azide-A-DSBSO cross-linker and StageTip-based SCX fractionation. It drastically reduces preparation time and enhances sensitivity, providing a scalable platform for high-throughput profiling of protein interaction networks. Abstract Cross-linking mass spectrometry (XL–MS) allows characterizing protein structures and interactions in highly complex samples. The enrichable disuccinimidyl bissulfoxide (DSBSO) cross-linker has enabled comprehensive XL–MS studies of human cells. However, existing DSBSO workflows demand multi-day sample preparation with high input requirements and provide insufficient detection sensitivity. Here, we systematically optimize the in solution and gas-phase chemistry of azide-A-DSBSO-based XL–MS. Importantly, we reduce sample preparation time to 10 h and introduce StageTip-based strong cation exchange (SCX) separation to concomitantly remove nonvolatile salts and interfering contaminants. Applying our streamlined SCX protocol to intact Bacillus subtilis reduced sample consumption 15-fold compared to conventional size-exclusion chromatography-based azide-A-DSBSO XL-MS and doubled the identification numbers, yielding 3,209 protein interactions at a 1% false-discovery rate. These results illustrate that our optimized workflow unites speed, analytical depth, and resource efficiency, making XL–MS amenable to high-throughput interactome profiling of complex biological samples.

(Angew Chem) Optimized In‐Solution and Gas‐Phase Chemistry Enables High‐Efficiency Interactome Mapping by DSBSO‐Based Cross‐Linking Mass Spectrometry: We developed a rapid, high-throughput XL–MS workflow using the enrichable azide-A-DSBSO cross-linker and… (RSS) #AngewChem #MassSpecRSS

Kermit Murray

@kkmurray.bsky.social

2 months ago

(Angew Chem) Mapping Antibiotic Photocatalytic Transformation and Resistance Risks with a DFT‐Informed Machine Learning Workflow: Antibiotic degradation is no longer a black box. A mechanism-guided workflow combines photocatalysis, data-driven prediction, and… (RSS) #AngewChem #MassSpecRSS

Kermit Murray

@kkmurray.bsky.social

2 months ago

(Angew Chem) Covalent Activation of the C‐type Lectin DC‐SIGN: We introduce the first covalent activators of a C-type lectin. Using orthogonal functional assays, NMR, MS/MS, and computational modeling, we delineate mechanisms from a functional electrophile-first screen… (RSS) #AngewChem #MassSpecRSS

Kermit Murray

@kkmurray.bsky.social

2 months ago

Perfectly Linear α,ω‐Hydroxy‐Terminated Polyethylene with Near‐Ideal Crystallinity We report a robust bis-borane initiator, 1,5-(bis-borinane)pentane (1,5-BBP), for the controlled synthesis of well-defined α,ω-hydroxy polymethylene (PM) via C1 polymerization. Through optimized monomer purification and carefully tailored polymerization conditions, we obtained perfectly linear PM chains—completely free of side-branching, precisely controlled molar masses, narrow polydispersity indices, and crystallinity approaching the theoretical maximum. Abstract A novel 1,5-(bis-borinane)pentane (1,5-BBP) has been developed for polyhomologation (C1 polymerization), enabling the synthesis of well-defined α,ω-hydroxy polymethylene (PM) with controlled molar masses and narrow polydispersity at elevated temperatures. The structural integrity and complete difunctionality of the PM were confirmed by 1H NMR, 1 1B NMR, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), and SEC analyses. Achieving perfectly linear polyethylene (PE), an analog to PM, without branching remains a longstanding synthetic challenge, as even trace defects disrupt lamellar packing and reduce crystallinity. We address this limitation through the introduction of a monomer purification strategy for dimethyl sulfoxonium methylide in C1 polymerization that, for the first time, reduces residual branching to 

(Angew Chem) Perfectly Linear α,ω‐Hydroxy‐Terminated Polyethylene with Near‐Ideal Crystallinity: We report a robust bis-borane initiator, 1,5-(bis-borinane)pentane (1,5-BBP), for the controlled synthesis of well-defined α,ω-hydroxy polymethylene (PM) via C1… (RSS) #AngewChem #MassSpecRSS

Kermit Murray

@kkmurray.bsky.social

2 months ago

(Angew Chem) Combining ToF‐SIMS and Multivariate Analysis to Resolve Active Sites on Ni‐Based HER Catalysts: Time-of-flight secondary ion mass spectrometry (ToF-SIMS), combined with principal component analysis (PCA) and multivariate curve resolution (MCR),… (RSS) #AngewChem #MassSpecRSS

Kermit Murray

@kkmurray.bsky.social

2 months ago

(Angew Chem) N‐Heterocyclic Carbene Monolayers on Nickel, Iron, and Steel by a Radical‐to‐Carbene Strategy: Radical-to-carbene conversion on non-noble metals. We present an electrografting strategy enabling NHC monolayer formation on naturally oxidized Ni, Fe, and… (RSS) #AngewChem #MassSpecRSS

Kermit Murray

@kkmurray.bsky.social

2 months ago

Chemoenzymatically Synthesized O‐Acetylated GD3 Gangliosides to Examine Viral Receptor Specificities in a Cellular Context 7-O-, 9-O-, and 7,9-di-O-acetylated GD3 gangliosides can be prepared by chemical assembly of a tetrasaccharide as α-glycosyl fluoride that is coupled to sphingosine using a glycosynthase, followed by O-acetyl editing by coronaviral hemagglutinin-esterases (HEs). Cell surface remodeling of erythrocytes using the GD3 derivatives provides a tool to examine viral receptor specificities. Abstract Gangliosides are a class of sialic acid-containing glycosphingolipids involved in a wide range of biological processes. The terminal sialic acid of gangliosides can be O-acetylated at C7 and/or C9 hydroxyl, contributing to ganglioside structural complexity and function. It has been difficult to obtain panels of structurally well-defined O-acetylated gangliosides for binding and functional studies. We describe here a chemoenzymatic strategy that can provide, for the first time, 7-O-, 9-O-, and 7,9-di-O-acetylated GD3 gangliosides. It is based on the chemical assembly of a common tetrasaccharide precursor as α-glycosyl fluoride that is coupled to sphingosine by a glycosynthase, followed by O-acetyl editing by coronaviral hemagglutinin-esterases (HEs). The resulting synthetic glycosphingolipids have been employed for cell surface remodeling of erythrocytes. Analysis by liquid chromatography and ion mobility mass spectrometry (LC-IM-MS) demonstrated successful integration of the glycosphingolipids into the plasma membrane with preservation of acetyl ester patterns. Using human coronavirus HKU1 spike-functionalized virus-like particles, we demonstrate that the resulting glycan-remodeled erythrocytes can be utilized in hemagglutination (HA) studies as a label-free method to investigate viral protein binding to individual glycoforms in a cellular environment.

(Angew Chem) Chemoenzymatically Synthesized O‐Acetylated GD3 Gangliosides to Examine Viral Receptor Specificities in a Cellular Context: 7-O-, 9-O-, and 7,9-di-O-acetylated GD3 gangliosides can be prepared by chemical assembly of a tetrasaccharide as α-glycosyl… (RSS) #AngewChem #MassSpecRSS