OPTICS: Operant Probability Theory in Crystal Solutions, Application of ssNMR, and Probability Theory in Polymorph Identification

Valdivia‐Berroeta, Gabriel A.; Sarpal, Kanika; Gonnella, Nina C.

doi:10.1021/acs.cgd.1c00797

Cited by 5 publications

(3 citation statements)

References 70 publications

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“…113 Besides, polymorph identification in solid state NMR has been supported by calculation of nuclear shielding tensor. 114 Solid state NMR studies represent a very efficient tool, providing insight into structures, mechanisms and dynamics of crystalline catalysts. For this purpose, as a support of the experimental work, 51 V nuclear shielding was theoretically predicted in molecular crystals.…”

Section: Nuclear Shielding Prediction In Natural Productsmentioning

confidence: 99%

Nuclear Magnetic Resonance

米本理¹

2022

Nuclear Magnetic Resonance

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The selected research papers on theoretical aspects of nuclear magnetic shielding published from 1 January to 31 December 2021 are shortly reviewed in this chapter. Among the reported studies are mainly density functional theory (DFT) predictions of nuclear shielding for free molecules, as well as in solution, modeled by the polarizable continuum model (PCM). The calculations for solids are getting more common in the reviewed period of time. Due to their relatively high computational price, the number of ab initio and highlevel calculated nuclear shieldings is significantly lower. In several reports the theoretical results are additionally improved by inclusion of zero-point vibration and temperature correction (ZPVC and TC), As before, most calculations have been performed using the non-relativistic approach.

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Section: Nuclear Shielding Prediction In Natural Productsmentioning

confidence: 99%

Nuclear Magnetic Resonance

米本理¹

2022

Nuclear Magnetic Resonance

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“…A similar approach was employed by Valdivia-Berroeta et al, for the identification of the correct polymorph of relevant pharmaceutical compounds. [27] Our work aims to highlight the use of the CSP-NMRX approach to solve systems that combine tautomerism and polymorphism, i. e. systems where the positions of hydrogen atoms and double bonds play a role in determining the crystal packing. In this paper we applied the CSP-NMRX method for the structure determination of the crystal phases of mebendazole (methyl 5-benzoyl-2-benzimidazole carbamate, Mbz).…”

Section: Introductionmentioning

confidence: 99%

Solid‐State NMR‐Driven Crystal Structure Prediction of Molecular Crystals: The Case of Mebendazole

Bravetti

Bordignon

Alig

et al. 2021

Chemistry A European J

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Among all possible NMR crystallography approaches for crystal-structure determination, crystal structure prediction -NMR crystallography (CSP-NMRX) has recently turned out to be a powerful method. In the latter, the original procedure exploited solid-state NMR (SSNMR) information during the final steps of the prediction. In particular, it used the comparison of computed and experimental chemical shifts for the selection of the correct crystal packing. Still, the prediction procedure, generally carried out with DFT methods, may require important computational resources and be quite time-consuming, especially if there are no available constraints to use at the initial stage. Herein, the successful application of this combined prediction method, which exploits NMR information also in the input step to reduce the search space of the predictive algorithm, is presented. Herein, this method was applied on mebendazole, which is characterized by desmotropism. The use of SSNMR data as constraints for the selection of the right tautomer and the determination of the number of independent molecules in the unit cell led to a considerably faster process, reducing the number of calculations to be performed. In this way, the crystal packing was successfully predicted for the three known phases of mebendazole. To evaluate the quality of the predicted structures, these were compared to the experimental ones. The crystal structure of phase B of mebendazole, in particular, was determined de novo by powder diffraction and is presented for the first time in this paper.

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“…Its ability to assume different solid-state phases forming anhydrous, hydrated, and solvated polymorphs [2][3][4][5][6][7][8][9][10] represents the reason of the intense research work developed around its polymorphism. When it comes to the pharmaceutical industry, the control of the possible solid forms and, therefore, of the physicochemical properties such as bioavailability, solubility and stability is the basic requirement in drug development [11][12][13][14][15] and a key point of patenting.…”

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confidence: 99%

Crystal structure determination of the antipsychotic drug of olanzapine form III

Anyfanti,

Husanu,

Andrusenko

et al. 2024

Preprint

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Olanzapine, an antipsychotic drug, is well known for its complex polymorphism. Although widely investigated, the crystal structure of one of its anhydrous polymorphs, form III, is still unknown. Its appearance, always in concomitance with form II and I, and the impossibility of isolating it from that mixture, has prevented its structure determination so far. The scenario has changed with the emerging field of 3D electron diffraction (3D ED) technique and its great advantages in the characterization of polyphasic mixture of nanosized crystals. In this study we show how the application of 3D ED allows the ab-initio structure determination and dynamical refinement of this elusive crystal structure unknown for more than 20 years. Olanzapine form III is monoclinic and shows a similar but shifted packing with respect to form II. It is remarkably different from the lowest energy structures predicted by the energy minimization algorithms of crystal structure prediction.

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OPTICS: Operant Probability Theory in Crystal Solutions, Application of ssNMR, and Probability Theory in Polymorph Identification

Cited by 5 publications

References 70 publications

Nuclear Magnetic Resonance

Nuclear Magnetic Resonance

Solid‐State NMR‐Driven Crystal Structure Prediction of Molecular Crystals: The Case of Mebendazole

Crystal structure determination of the antipsychotic drug of olanzapine form III

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