17O NMR Research Articles

Semi-Rigid (Aminomethyl) Piperidine-Based Pentadentate Ligands for Mn(II) Complexation.

Two pentadentate ligands built on the 2-aminomethylpiperidine structure and bearing two tertiary amino and three oxygen donors (three carboxylates in the case of AMPTA and two carboxylates and one phenolate for AMPDA-HB) were developed for Mn(II) complexation. Equilibrium studies on the ligands and the Mn(II) complexes were carried out using pH potentiometry, 1H-NMR spectroscopy and UV-vis spectrophotometry. The Mn complexes that were formed by the two ligands were more stable than the Mn complexes of other pentadentate ligands but with a lower pMn than Mn(EDTA) and Mn(CDTA) (pMn for Mn(AMPTA) = 7.89 and for Mn(AMPDA-HB) = 7.07). 1H and 17O-NMR relaxometric studies showed that the two Mn-complexes were q = 1 with a relaxivity value of 3.3 mM−1 s−1 for Mn(AMPTA) and 3.4 mM−1 s−1 for Mn(AMPDA-HB) at 20 MHz and 298 K. Finally, the geometries of the two complexes were optimized at the DFT level, finding an octahedral coordination environment around the Mn2+ ion, and MD simulations were performed to monitor the distance between the Mn2+ ion and the oxygen of the coordinated water molecule to estimate its residence time, which was in good agreement with that determined using the 17O NMR data.

Two- and Three-Dimensional 13C-17O Heteronuclear Correlation NMR Spectroscopy for Studying Organic and Biological Solids.

We report two- and three-dimensional (2D and 3D) 13C-17O heteronuclear correlation solid-state NMR experiments under magic-angle spinning (MAS) conditions. These experiments utilize the D-RINEPT (Dipolar-mediated Refocused Insensitive Nuclei Enhanced by Polarization Transfer) scheme with symmetry-based SR412 recoupling blocks for coherence transfer between 13C and 17O nuclei. First, a 2D 17O → 13C correlation experiment was performed for the [1-13C,17O]-Gly/Gly·HCl cocrystal and [U-13C, 1-17O]-α/β-d-glucose samples. Second, a 2D 17O → 13C MQ-D-RINEPT correlation experiment where the indirect dimension incorporates the multiple-quantum MAS (MQMAS) scheme was tested for obtaining isotropic 17O resolution with [U-13C, 1-17O]-α/β-d-glucose. Third, a new 3D 17O → 13C → 13C correlation experiment was demonstrated where 17O → 13C and 13C → 13C correlations are achieved by D-RINEPT and DARR (Dipolar Assisted Rotational Resonance) sequences, respectively (thus termed as a 3D D-RINEPT/DARR OCC experiment). This new 3D 17O NMR experiment is implemented with the aim for site-resolved solid-state 17O NMR studies.

Comparison of phosphonate, hydroxypropyl and carboxylate pendants in Fe(III) macrocyclic complexes as MRI contrast agents

Fe(III) macrocyclic complexes containing a macrocycle and three pendant groups including phosphonate (NOTP =1,4,7-triazacyclononane-1,4,7-triyl-tris(methylenephosphonic acid), carboxylate (NOTA = 1,4,7 - triazacyclononane - N,N′,N″ – triacetate) or hydroxypropyl (NOHP =(2S,2’S,2”S)-1,1′,1″-(1,4,7-triazonane-1,4,7-triyl)tris(propan-2-ol)) were studied in order to compare the effect of these donor groups on solution chemistry and water proton relaxivity. All three complexes, Fe(NOTP), Fe(NOHP) and Fe(NOTA), display a large degree of kinetic inertness to dissociation in the presence of phosphate and carbonate, under acidic conditions of 100 mM HCl or 1 M HCl or to trans-metalation with Zn(II). The r1 proton relaxivity of the complexes at 1.4 T, 33 °C is compared over the pH range of 1 to 10. At pH 7.4, 33 °C, 1.4 T, Fe(NOHP) has the largest relaxivity (1.5 mM−1 s−1), Fe(NOTP) is second at 1.0 mM−1 s−1, whereas Fe(NOTA) is the lowest at 0.61 mM−1 s−1. Fe(NOTP), Fe(NOHP) and Fe(NOTA) all show an increase in relaxivity at very acidic pH values (< 3) that is consistent with an acid-catalyzed process. Variable temperature 17O NMR studies at near neutral pH are consistent with the absence of an inner-sphere water molecule for Fe(NOTP) and Fe(NOHP), supporting second-sphere or outer-sphere water contributions to proton relaxation. Fe(NOTP) shows contrast enhancement in T1 weighted MRI studies in mice and clears through a renal pathway.

Activation of H2O2 over Zr(IV). Insights from Model Studies on Zr-Monosubstituted Lindqvist Tungstates

Zr-monosubstituted Lindqvist-type polyoxometalates (Zr-POMs), (Bu4N)2[W5O18Zr(H2O)3] (1) and (Bu4N)6[{W5O18Zr(μ-OH)}2] (2), have been employed as molecular models to unravel the mechanism of hydrogen peroxide activation over Zr(IV) sites. Compounds 1 and 2 are hydrolytically stable and catalyze the epoxidation of C═C bonds in unfunctionalized alkenes and α,β-unsaturated ketones, as well as sulfoxidation of thioethers. Monomer 1 is more active than dimer 2. Acid additives greatly accelerate the oxygenation reactions and increase oxidant utilization efficiency up to >99%. Product distributions are indicative of a heterolytic oxygen transfer mechanism that involves electrophilic oxidizing species formed upon the interaction of Zr-POM and H2O2. The interaction of 1 and 2 with H2O2 and the resulting peroxo derivatives have been investigated by UV–vis, FTIR, Raman spectroscopy, HR-ESI-MS, and combined HPLC-ICP-atomic emission spectroscopy techniques. The interaction between an 17O-enriched dimer, (Bu4N)6[{W5O18Zr(μ-OCH3)}2] (2′), and H2O2 was also analyzed by 17O NMR spectroscopy. Combining these experimental studies with DFT calculations suggested the existence of dimeric peroxo species [(μ-η2:η2-O2){ZrW5O18}2]6– as well as monomeric Zr-hydroperoxo [W5O18Zr(η2-OOH)]3– and Zr-peroxo [HW5O18Zr(η2-O2)]3– species. Reactivity studies revealed that the dimeric peroxo is inert toward alkenes but is able to transfer oxygen atoms to thioethers, while the monomeric peroxo intermediate is capable of epoxidizing C═C bonds. DFT analysis of the reaction mechanism identifies the monomeric Zr-hydroperoxo intermediate as the real epoxidizing species and the corresponding α-oxygen transfer to the substrate as the rate-determining step. The calculations also showed that protonation of Zr-POM significantly reduces the free-energy barrier of the key oxygen-transfer step because of the greater electrophilicity of the catalyst and that dimeric species hampers the approach of alkene substrates due to steric repulsions reducing its reactivity. The improved performance of the Zr(IV) catalyst relative to Ti(IV) and Nb(V) catalysts is respectively due to a flexible coordination environment and a low tendency to form energy deep-well and low-reactive Zr-peroxo intermediates.

Labeling and Probing the Silica Surface Using Mechanochemistry and 17 O NMR Spectroscopy*.

In recent years, there has been increasing interest in developing cost‐efficient, fast, and user‐friendly 17O enrichment protocols to help to understand the structure and reactivity of materials by using 17O NMR spectroscopy. Here, we show for the first time how ball milling (BM) can be used to selectively and efficiently enrich the surface of fumed silica, which is widely used at industrial scale. Short milling times (up to 15 min) allowed modulation of the enrichment level (up to ca. 5 %) without significantly changing the nature of the material. High‐precision 17O compositions were measured at different milling times by using large‐geometry secondary‐ion mass spectrometry (LG‐SIMS). High‐resolution 17O NMR analyses (including at 35.2 T) allowed clear identification of the signals from siloxane (Si−O−Si) and silanols (Si−OH), while DNP analyses, performed by using direct 17O polarization and indirect 17O{1H} CP excitation, agreed with selective labeling of the surface. Information on the distribution of Si−OH environments at the surface was obtained from 2D 1H−17O D‐HMQC correlations. Finally, the surface‐labeled silica was reacted with titania and using 17O DNP, their common interface was probed and Si−O−Ti bonds identified.

Chalcogen‐Bonding Catalysis with Telluronium Cations

AbstractChalcogen bonding results from non‐covalent interactions occurring between electrodeficient chalcogen atoms and Lewis bases. Among the chalcogens, tellurium is the strongest Lewis acid, but Te‐based compounds are scarcely used as organocatalysts. For the first time, telluronium cations demonstrated impressive catalytic properties at low loadings in three benchmark reactions: the Friedel–Crafts bromination of anisole, the bromolactonization of ω‐unsaturated carboxylic acids and the aza‐Diels–Alder between Danishefsky's diene and imines. The ability of telluronium cations to interact with a Lewis base through chalcogen bonding was demonstrated on the basis of multi‐nuclear (17O, 31P, and 125Te) NMR analysis and DFT calculations.

Imidazole-Based Ionic Liquids with BF4 as the Counterion Perform Outstanding Abilities in Both Inhibiting Clay Swelling and Lowing Water Cluster Size.

Promoting fluid transportation in porous media has important applications in energy, pedology, bioscience, etc. For this purpose, one effective way is to prevent swelling through surface modification; however, it is far from enough in real cases, such as ultra-low permeability reservoirs and tight oils. In this study, we considered the comprehensive effects of inhibiting clay swelling, flocculation performance, reducing water clusters and interfacial tension and developed a series of imidazole-based tetrafluoroborate ionic liquids (ILs) with different lengths of alkyl chains. Through measurements of anti-swelling rates, XRD, SEM, 17O NMR, molecular dynamics simulation, zeta potential, flocculation evaluation, interfacial tension and a core flooding experiment based on ultra-low permeability reservoirs, the relationships between the molecular structure and physicochemical properties of ILs have been revealed. Interestingly, one of the selected ILs, imidazole-based tetrafluoroborate ILs (C8-OMImBF4), shows excellent performance, which is helpful to design an effective strategy in promoting fluid transportation in narrow spaces.

Dinuclear Fe(III) Hydroxypropyl-Appended Macrocyclic Complexes as MRI Probes.

Four high-spin Fe(III) macrocyclic complexes, including three dinuclear and one mononuclear complex, were prepared toward the development of more effective iron-based magnetic resonance imaging (MRI) contrast agents. All four complexes contain a 1,4,7-triazacyclononane macrocyclic backbone with two hydroxypropyl pendant groups, an ancillary aryl or biphenyl group, and a coordination site for a water ligand. The pH potentiometric titrations support one or two deprotonations of the complexes, most likely deprotonation of hydroxypropyl groups at near-neutral pH. Variable-temperature 17O NMR studies suggest that the inner-sphere water ligand is slow to exchange with bulk water on the NMR time scale. Water proton T1 relaxation times measured for solutions of the Fe(III) complexes at pH 7.2 showed that the dinuclear complexes have a 2- to 3-fold increase in r1 relaxivity in comparison to the mononuclear complex per molecule at field strengths ranging from 1.4 T to 9.4 T. The most effective agent, a dinuclear complex with macrocycles linked through para-substitution of an aryl group (Fe2(PARA)), has an r1 of 6.7 mM-1 s-1 at 37 °C and 4.7 T or 3.3 mM-1 s-1 per iron center in the presence of serum albumin and shows enhanced blood pool and kidney contrast in mice MRI studies.

Mg2+ Solvation Structures and Diffusion Properties in Dimethoxyethane Solutions Using Multimodal NMR Analysis

Mg-based secondary battery systems represent a promising advancement over current technology, however a detailed molecular view of the battery components are lacking which prevents the implementation of such technologies. Diffusion behaviors of Mg2+ in electrolytes are usually not as readily accessible as Li+ and Na+ through PFG NMR, due to the low sensitivity and resolution of 25Mg NMR. Herein, we report the evolution of solvation structures and diffusion behaviors in the traditional MgTFSI2/DME based electrolyte using quantitative multinuclear (1H, 19F, 17O) NMR, NMR relaxation, 2D 1H EXSY NMR, as well as PFG diffusion measurements. High resolution 1H NMR reveals bound DME (DME molecules coordinating to Mg2+) and bulk DME (“free” diffusing DME) within solution structure, where the diffusion of bound DME provides informatin about Mg2+ diffusion through a two-site exchange-diffusion model. We concluded that the dominant solvation structure evolves from contact ion pairs (i.e. [Mg(TFSI)(DME)1-2]+) to fully solvated clusters (i.e. [Mg(DME)3]2+) as salt concentration increases or as temperature decreases. This transition is coupled to a phase separation between 0.06 M and 0.36 M. Subsequent analysis is based on an explanation of the solvent rearrangement process and the competition between solvent molecules and TFSI anions for cation coordination. Furthermore, the comparison between diffusion behaviros of Mg2+ and TFSI- reveals the formation of supercluster structures that highly constrain Mg2+ diffusion at high concentrations and low temperatures but present little restricticiton to TFSI- diffusion, properbly due to the long-distance effect of multivalent Mg2+ on DME with suppressed motion under these conditions.

Mn2+ Complexes with Pyclen-Based Derivatives as Contrast Agents for Magnetic Resonance Imaging: Synthesis and Relaxometry Characterization.

Magnetic resonance imaging (MRI) has a leading place in medicine as an imaging tool of high resolution for anatomical studies and diagnosis of diseases, in particular for soft tissues that cannot be accessible by other modalities. Many research works are thus focused on improving the images obtained with MRI. This technique has indeed poor sensitivity, which can be compensated by using a contrast agent (CA). Today, the clinically approved CAs on market are solely based on gadolinium complexes that may induce nephrogenic systemic fibrosis for patients with kidney failure, whereas more recent studies on healthy rats also showed Gd retention in the brain. Consequently, researchers try to elaborate other types of safer MRI CAs like manganese-based complexes. In this context, the synthesis of Mn2+ complexes of four 12-membered pyridine-containing macrocyclic ligands based on the pyclen core was accomplished and described herein. Then, the properties of these Mn(II) complexes were studied by two relaxometric methods, 17O NMR spectroscopy and 1H NMR dispersion profiles. The time of residence (τM) and the number of water molecules (q) present in the inner sphere of coordination were determined by these two experiments. The efficacy of the pyclen-based Mn(II) complexes as MRI CAs was evaluated by proton relaxometry at a magnetic field intensity of 1.41 T near those of most medical MRI scanners (1.5 T). Both the 17O NMR and the nuclear magnetic relaxation dispersion profiles indicated that the four hexadentate ligands prepared herein left one vacant coordination site to accommodate one water molecule, rapidly exchanging, in around 6 ns. Furthermore, it has been shown that the presence of an additional amide bond formed when the paramagnetic complex is conjugated to a molecule of interest does not alter the inner sphere of coordination of Mn, which remains monohydrated. These complexes exhibit r1 relaxivities, large enough to be used as clinical MRI CAs (1.7-3.4 mM-1·s-1, at 1.41 T and 37 °C).

Characterization of the ionic liquid obtained by chlorosulfonation of 1-methylimidazole: 1-methyl-3-sulfonic acid imidazolium chloride, 1-methylimidazolium chlorosulfate or a zwitterionic salt?

A great number of organic reactions catalyzed by the ionic liquid product of chlorosulfonation of 1-methylimidazole have been reported recently. At the same time controversial assumptions have appeared on the real structure of the catalyst. In the present report the primarily formed chlorosulfonation product is proved to be 1-methylimidazolium chlorosulfate ([HMim]+[SO3Cl]−) instead of 1-methyl-3-sulfonic acid imidazolium chloride, reported previously. The former structure is confirmed by X-ray crystallography and NMR spectroscopy, including 1H-, 13C-, 17O- and 15N–1H HSQC measurements. 1H and 17O NMR experiments support fast hydrolysis of [HMim] [SO3Cl] resulting in the formation of [HMim][HSO4] in the presence of traces of water.

17O NMR spectroscopy of crystalline microporous materials.

Microporous materials, containing pores and channels of similar dimensions to small molecules have a range of applications in catalysis, gas storage and separation and in drug delivery. Their complex structure, often containing different types and levels of positional, compositional and temporal disorder, makes structural characterisation challenging, with information on both long-range order and the local environment required to understand the structure–property relationships and improve the future design of functional materials. In principle, 17O NMR spectroscopy should offer an ideal tool, with oxygen atoms lining the pores of many zeolites and phosphate frameworks, playing a vital role in host–guest chemistry and reactivity, and linking the organic and inorganic components of metal–organic frameworks (MOFs). However, routine study is challenging, primarily as a result of the low natural abundance of this isotope (0.037%), exacerbated by the presence of the quadrupolar interaction that broadens the spectral lines and hinders the extraction of information. In this Perspective, we will highlight the current state-of-the-art for 17O NMR of microporous materials, focusing in particular on cost-effective and atom-efficient approaches to enrichment, the use of enrichment to explore chemical reactivity, the challenge of spectral interpretation and the approaches used to help this and the information that can be obtained from NMR spectra. Finally, we will turn to the remaining challenges, including further improving sensitivity, the high-throughput generation of multiple structural models for computational study and the possibility of in situ and in operando measurements, and give a personal perspective on how these required improvements can be used to help solve important problems in microporous materials chemistry.

The Industrial Production of Water Dedicated to Absorption of Gases

The paper presents a flow plasma reactor permitting modification of the properties of water/aqueous solutions by stochastic resonance amplification of vibrations of selected chemical species in water with electromagnetic noise generated during a plasma discharge. The main parameters characterizing the quality for super-pure water, tap water and water from the intake in Besko (Poland) before and after the process in the plasma reactor were presented for comparison. In addition, the 17O NMR (the full width at half maximum) and electrospray ionization mass spectrometry (ESI MS) methods were used to determine differences in physicochemical parameters between the untreated and plasma-treated water. It has been established that the water subjected to plasma treatment shows much different gas absorption properties than the untreated water samples, as a function of temperature and pressure, in this paper we report exemplary data for CO2, oxygen and acetylene. The improved gas absorption properties of the plasma-treated water make it attractive for the use in industrial processes. It is worth pointing to a great capacity of the new reactor (4000 l/h), and low energy consumption (20 MJ/h) for the treatment of the above mentioned volume flow rate of water.

Defining the conditions for the development of the emerging class of FeIII-based MRI contrast agents.

Fe(iii) complexes are attracting growing interest in chemists developing diagnostic probes for Magnetic Resonance Imaging because they leverage on an endogenous metal and show superior stability. However, in this case a detailed understanding of the relationship between the chemical structure of the complexes, their magnetic, thermodynamic, kinetic and redox properties and the molecular parameters governing the efficacy (relaxivity) is still far from being available. We have carried out an integrated 1H and 17O NMR relaxometric study as a function of temperature and magnetic field, on the aqua ion and three complexes chosen as reference models, together with theoretical calculations, to obtain accurate values of the parameters that control their relaxivity. Moreover, thermodynamic stability and dissociation kinetics of the Fe(iii) chelates, measured in association with the ascorbate reduction behaviour, highlight their role and mutual influence in achieving the stability required for use in vivo.

Natural abundance oxygen-17 solid-state NMR of metal organic frameworks enhanced by dynamic nuclear polarization.

The 17O resonances of zirconium-oxo clusters that can be found in porous Zr carboxylate metal-organic frameworks (MOFs) have been investigated by magic-angle spinning (MAS) NMR spectroscopy enhanced by dynamic nuclear polarization (DNP). High-resolution 17O spectra at 0.037% natural abundance could be obtained in 48 hours, thanks to DNP enhancement of the 1H polarization by factors ε(1H) = Swith/Swithout = 28, followed by 1H → 17O cross-polarization, allowing a saving in experimental time by a factor of ca. 800. The distinct 17O sites from the oxo-clusters can be resolved at 18.8 T. Their assignment is supported by density functional theory (DFT) calculations of chemical shifts and quadrupolar parameters. Protonation of 17O sites seems to be leading to large characteristic shifts. Hence, natural abundance 17O NMR spectra of diamagnetic MOFs can thus be used to probe and characterize the local environment of different 17O sites on an atomic scale.

Scrutinising the role of intramolecular hydrogen bonding in water exchange dynamics of Gd(III) complexes.

We report a series of structurally related Gd(iii) complexes designed to modulate the exchange of the coordinated water molecule, which is an important parameter to be controlled to achieve optimal performance of contrast agents for application in magnetic resonance imaging (MRI). The ligands contain a DO3A scafold functionalised with 2'-methoxyphenacyl or 4'-methoxyphenacyl groups (DO3A-oMAP and DO3A-pMAP), a 2'-aminophenacyl group (DO3A-oAnAP) or a 2',4'-dihydroxyphenacyl moiety (DO3A-DiHAP). The results are compared with those obtained previously for the analogues containing 2'- or 4'-hydroxyphenacyl groups (DO3A-oHAP and DO3A-pHAP, respectively) and the parent system with an unsubstituted acetophenone pendant arm (DO3A-AP). 1H NMR studies performed on the Eu(iii) complexes show that ligand functionalisation causes a very minor effect on the relative populations of the SAP and TSAP isomers present in solution, with the SAP isomer representing 70-80% of the overall population. The emission spectra of the Eu(iii) complexes confirm the presence of a water molecule coordinated to the metal center and point to similar coordination environments around the metal ion. The analysis of the 1H NMRD profiles and 17O NMR data recorded for the Gd(iii) complexes evidences that water exchange is modulated by the ability of peripherical substituents to establish hydrogen bonds with the coordinated and/or second sphere water molecules. DFT calculations were used to model the transition states responsible for the dissociative water exchange mechanism, providing support to the crucial role of hydrogen-bonds in accelerating water exchange.

Modelling and simulation of 13C, 15N, 17O NMR chemical shifts, 17O and 14N electric field gradients and measurement of 13C and 15N chemical shifts in DNA/RNA of human gum cancer cells, tissues and tumors using NMR biospectroscopic profiling for novel systems diagnostics

Modelling and simulation of 13C, 15N, 17O NMR chemical shifts, 17O and 14N electric field gradients and measurement of 13C and 15N chemical shifts in DNA/RNA of human gum cancer cells, tissues and tumors using NMR biospectroscopic profiling for novel systems diagnostics

Expanding the NMR toolkit for biological solids: oxygen-17 enriched Fmoc-amino acids

We report the solid-state 17O NMR parameters for five previously uncharacterized N-α-fluoren-9-yl-methoxycarbonyl-O-t-butyl (Fmoc) protected amino acids.

Unveiling the Structure and Reactivity of Fatty-Acid Based (Nano)materials Thanks to Efficient and Scalable 17O and 18O-Isotopic Labeling Schemes.

Fatty acids are ubiquitous in biological systems and widely used in materials science, including for the formulation of drugs and the surface-functionalization of nanoparticles. However, important questions regarding the structure and reactivity of these molecules are still to be elucidated, including their mode of binding to certain metal cations or materials surfaces. In this context, we have developed novel, efficient, user-friendly, and cost-effective synthetic protocols based on ball-milling, for the 17O and 18O isotopic labeling of two key fatty acids which are widely used in (nano)materials science, namely stearic and oleic acid. Labeled molecules were analyzed by 1H and 13C solution NMR, IR spectroscopy, and mass spectrometry (ESI-TOF and LC-MS), as well as 17O solid state NMR (for the 17O labeled species). In both cases, the labeling procedures were scaled-up to produce up to gram quantities of 17O- or 18O-enriched molecules in just half-a-day, with very good synthetic yields (all ≥84%) and enrichment levels (up to an average of 46% per carboxylic oxygen). The 17O-labeled oleic acid was then used for the synthesis of a metal soap (Zn-oleate) and the surface-functionalization of ZnO nanoparticles (NPs), which were characterized for the first time by high-resolution 17O NMR (at 14.1 and 35.2 T). This allowed very detailed insight into (i) the coordination mode of the oleate ligand in Zn-oleate to be achieved (including information on Zn···O distances) and (ii) the mode of attachment of oleic-acid at the surface of ZnO (including novel information on its photoreactivity upon UV-irradiation). Overall, this work demonstrates the high interest of these fatty acid-enrichment protocols for understanding the structure and reactivity of a variety of functional (nano)materials systems using high resolution analyses like 17O NMR.

Structure and disorder in Pb‐Na metasilicate (PbO:Na2O:2SiO2) glasses: A view from high‐resolution 17O solid‐state NMR

AbstractKnowledge of the structure of lead (Pb)‐bearing silicate glasses, such as degree of polymerization and arrangement among cations, provides improved prospects for understanding their macroscopic properties. Despite the importance, the detailed disorder in Pb‐bearing silicate glasses with varying composition (i.e., Pb/alkali content) has not been systematically explored. Here, we reveal the first unambiguous structural information of PbO‐Na2O‐SiO2 glasses with varying PbO content [i.e., XPbO = PbO/(Na2O + PbO)], which are the fundamental model system for multicomponent Pb‐bearing glasses, using high‐resolution 17O solid‐state NMR. 17O NMR spectra clearly show the resolved multiple oxygen sites, such as Na‐O‐Si, Si‐O‐Si, and [Na,Pb]‐O‐Si. As XPbO increases, the fraction of [Na,Pb]‐O‐Si peak increases markedly at the expanse of substantial reduction in the fraction of Na‐O‐Si/total NBO. This trend indicates the relative predominance of the dissimilar pairs around non‐bridging oxygen (NBO) and, therefore, can be explained well with the pronounced chemical ordering among Na+ and Pb2+. These results confirm that Pb is primarily a network‐modifier in the glasses studied here. Atomic environments around both NBO and BO are affected by the change in Na/Pb ratio, while topological disorder due to cation mixing around NBO is much more prominent in Pb endmember. The structural details of short‐range configurations around oxygen in alkali Pb‐silicate glasses provide atomistic insights for understanding the properties of Pb‐bearing multicomponent silicate glasses.