Using HOESY NMR Spectroscopy to Characterize Prenucleation Aggregates

Bobrovs, Raitis; Auzins, Andrievs Auseklis; Drunka, Laura; Metlans, Rimants; Muhamadejev, Ruslan; Jaudzems, Kristaps

doi:10.1021/acs.cgd.1c00625

Cited by 4 publications

(5 citation statements)

References 39 publications

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“…Such a process has been recently proven by Bobrovs et al. who, while studying the prenucleation mechanism by means of HOESY NMR measurements, showed a high affinity of both co‐formers for the formation of binary systems [26] . Figure 9d depicts the 1 H‐ 19 F HOESY spectrum of a freshly prepared BA : PFBA/MCM‐41 sample.…”

Section: Resultsmentioning

confidence: 52%

“…Such a process has been recently proven by Bobrovs et al who, while studying the prenucleation mechanism by means of HOESY NMR measurements, showed a high affinity of both co-formers for the formation of binary systems. [26] Figure 9d depicts the 1 H- 19 F HOESY spectrum of a freshly prepared BA : PFBA/MCM-41 sample. The 2D NMR correlation takes 4 hours to acquire an appropriate number of serial files to achieve an acceptable resolution in an indirect dimension.…”

Section: Chemphyschemmentioning

confidence: 99%

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Unexpected Factors Affecting the Kinetics of Guest Molecule Release from Investigation of Binary Chemical Systems Trapped in a Single Void of Mesoporous Silica Particles

et al. 2023

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In this work, we present results for loading of well-defined binary systems (cocrystal, solid solution) and untreated materials (physical mixtures) into the voids of MCM-41 mesoporous silica particles employing three different filling methods. The applied techniques belong to the group of "wet methods" (diffusion supported loading -DiSupLo) and "solvent-free methods" (mechanical ball-mill loading -MeLo, thermal solvent free -TSF). As probes for testing the guest1-guest2 interactions inside the MCM-41 pores we employed the benzoic acid (BA), perfluorobenzoic acid (PFBA), and 4-fluorobenzoic acid (4-FBA).The guests intermolecular contacts and phase changes were monitored employing magic angle spinning (MAS) NMR Spectroscopy techniques and powder X-ray diffraction (PXRD). Since mesoporous silica materials are commonly used in drug delivery system research, special attention has been paid to factors affecting guest release kinetics. It has been proven that not only the content and composition of binary systems, but also the loading technique have a strong impact on the rate of guests release. Innovative methods of visualizing differences in release kinetics are presented.

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Section: Resultsmentioning

confidence: 52%

Section: Chemphyschemmentioning

confidence: 99%

Unexpected Factors Affecting the Kinetics of Guest Molecule Release from Investigation of Binary Chemical Systems Trapped in a Single Void of Mesoporous Silica Particles

et al. 2023

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“…Among the nuclei used in NMR, 1 H is the most important to study hydrogen-bond formation in solution. More sophisticated NMR techniques have also been extended to study co-crystal systems, e.g., Bobrovs et al have used heteronuclear Overhauser effect NMR spectroscopy (HOESY), to explore the interaction between benzoic acid and pentafluorobenzoic acid …”

Section: Introductionmentioning

confidence: 99%

Using Prenucleation Aggregation of Caffeine-Benzoic Acid as a Rapid Indication of Co-crystallization from Solutions

et al. 2023

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Co-crystal design is a convenient way to remedy the poor biopharmaceutical properties of drugs. Most studies focus on experimental co-crystal screening or computational prediction, but hardly any work has been done toward fast, efficient, and reliable prediction of solution crystallization for co-crystal formation. Here, we study the caffeine-benzoic acid co-crystal system, due to its reported difficulty to crystallize from the solution phase. With this work, we investigate whether there is a link between prenucleation aggregation in solution and co-crystal formation and how to harness this for crystallization prediction. 1 H and 13 C NMR spectroscopy is used to study the prenucleation interaction between caffeine and benzoic acid in methanol, acetone, and acetonitrile as examples of common solvents. In this system, crystallization from methanol leads to no co-crystallization, from acetone to concomitant crystallization of co-crystal and caffeine, and from acetonitrile to pure co-crystal formation from solution. Strong heteromeric dimers were found to exist in all three solvents. Ternary phase diagrams were defined and a solution-accessible co-crystal region was found for all solvents. For this system, the prenucleation clusters found in solution could be linked to the crystallization of the co-crystal. Crystallization from DMSO did not yield the co-crystal and there were no detectable prenucleation aggregates. NMR spectroscopy to probe dimers in solution can thus be used as a fast, reliable, and promising tool to predict co-crystallization from specific solvents and to screen for suitable solvents for manufacturing and scale-up.

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“…The phenomenon of nucleation has been studied for over 100 years, yet our understanding of fundamental nucleation processes is still very limited. − Nucleation plays an important role in a large number of processes across all areas of the natural sciences, for example, in the formation of bones and minerals in geology, − in the preparation of protein crystals in structural biology, ,,− but also across chemistry, , materials science, − and nanoscience. ,− Unlike organic chemistry, where synthesis pathways of molecules can be designed based on the precise knowledge of the movement of individual electrons in the synthesis process, the synthesis of solid-state inorganic materials to a large extent relies on a combination of large parameter studies and trial-and-error experiments. ,,− A greater understanding of nucleation of materials could facilitate the design of synthesis strategies of materials with much higher control. ,− As shown in 2008, Gebauer et al showed the formation of cluster species appearing prior to the nucleation of CaCO 3 . The discovery of these “prenucleation clusters” has in the past decade led to a large number of studies investigating the chemistry and interactions of the compounds and clusters formed before nucleation. ,,,− However, the role of prenucleation species in the nucleation process is still not clear. It is thus still an open question if the nature of the prenucleaction species themselves has an impact on the formed material, or if they are necessary intermediates in the chemical reaction which we cannot control.…”

Section: Introductionmentioning

confidence: 99%

Influence of the Precursor Structure on the Formation of Tungsten Oxide Polymorphs

Juelsholt,

Aalling-Frederiksen,

Lindahl Christiansen

et al. 2023

Inorg. Chem.

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Understanding material nucleation processes is crucial for the development of synthesis pathways for tailormade materials. However, we currently have little knowledge of the influence of the precursor solution structure on the formation pathway of materials. We here use in situ total scattering to show how the precursor solution structure influences which crystal structure is formed during the hydrothermal synthesis of tungsten oxides. We investigate the synthesis of tungsten oxide from the two polyoxometalate salts, ammonium metatungstate, and ammonium paratungstate. In both cases, a hexagonal ammonium tungsten bronze (NH4)0.25WO3 is formed as the final product. If the precursor solution contains metatungstate clusters, this phase forms directly in the hydrothermal synthesis. However, if the paratungstate B cluster is present at the time of crystallization, a metastable intermediate phase in the form of a pyrochlore-type tungsten oxide, WO3·0.5H2O, initially forms. The pyrochlore structure then undergoes a phase transformation into the tungsten bronze phase. Our studies thus experimentally show that the precursor cluster structure present at the moment of crystallization directly influences the formed crystalline phase and suggests that the precursor structure just prior to crystallization can be used as a tool for targeting specific crystalline phases of interest.

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Using HOESY NMR Spectroscopy to Characterize Prenucleation Aggregates

Cited by 4 publications

References 39 publications

Unexpected Factors Affecting the Kinetics of Guest Molecule Release from Investigation of Binary Chemical Systems Trapped in a Single Void of Mesoporous Silica Particles

Unexpected Factors Affecting the Kinetics of Guest Molecule Release from Investigation of Binary Chemical Systems Trapped in a Single Void of Mesoporous Silica Particles

Using Prenucleation Aggregation of Caffeine-Benzoic Acid as a Rapid Indication of Co-crystallization from Solutions

Influence of the Precursor Structure on the Formation of Tungsten Oxide Polymorphs

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