Sean T. Holmes, Cameron M. Boley, Angelika Dewicki, Zachary T. Gardner, Cameron S. Vojvodin, Robbie J. Iuliucci, Robert W. Schurko
{"title":"氮密集化合物的碳-13 化学位移张量测量。","authors":"Sean T. Holmes, Cameron M. Boley, Angelika Dewicki, Zachary T. Gardner, Cameron S. Vojvodin, Robbie J. Iuliucci, Robert W. Schurko","doi":"10.1002/mrc.5422","DOIUrl":null,"url":null,"abstract":"<p>This paper reports the principal values of the <sup>13</sup>C chemical shift tensors for five nitrogen-dense compounds (i.e., cytosine, uracil, imidazole, guanidine hydrochloride, and aminoguanidine hydrochloride). Although these are all fundamentally important compounds, the majority do not have <sup>13</sup>C chemical shift tensors reported in the literature. The chemical shift tensors are obtained from <sup>1</sup>H→<sup>13</sup>C cross-polarization magic-angle spinning (CP/MAS) experiments that were conducted at a high field of 18.8 T to suppress the effects of <sup>14</sup>N-<sup>13</sup>C residual dipolar coupling. Quantum chemical calculations using density functional theory are used to obtain the <sup>13</sup>C magnetic shielding tensors for these compounds. The best agreement with experiment arises from calculations using the hybrid functional PBE0 or the double-hybrid functional PBE0-DH, along with the triple-zeta basis sets TZ2P or pc-3, respectively, and intermolecular effects modeled using large clusters of molecules with electrostatic embedding through the COSMO approach. These measurements are part of an ongoing effort to expand the catalog of accurate <sup>13</sup>C chemical shift tensor measurements, with the aim of creating a database that may be useful for benchmarking the accuracy of quantum chemical calculations, developing nuclear magnetic resonance (NMR) crystallography protocols, or aiding in applications involving machine learning or data mining. This work was conducted at the National High Magnetic Field Laboratory as part of a 2-week school for introducing undergraduate students to practical laboratory experience that will prepare them for scientific careers or postgraduate studies.</p>","PeriodicalId":18142,"journal":{"name":"Magnetic Resonance in Chemistry","volume":null,"pages":null},"PeriodicalIF":1.9000,"publicationDate":"2024-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Carbon-13 chemical shift tensor measurements for nitrogen-dense compounds\",\"authors\":\"Sean T. Holmes, Cameron M. Boley, Angelika Dewicki, Zachary T. Gardner, Cameron S. Vojvodin, Robbie J. Iuliucci, Robert W. Schurko\",\"doi\":\"10.1002/mrc.5422\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p>This paper reports the principal values of the <sup>13</sup>C chemical shift tensors for five nitrogen-dense compounds (i.e., cytosine, uracil, imidazole, guanidine hydrochloride, and aminoguanidine hydrochloride). Although these are all fundamentally important compounds, the majority do not have <sup>13</sup>C chemical shift tensors reported in the literature. The chemical shift tensors are obtained from <sup>1</sup>H→<sup>13</sup>C cross-polarization magic-angle spinning (CP/MAS) experiments that were conducted at a high field of 18.8 T to suppress the effects of <sup>14</sup>N-<sup>13</sup>C residual dipolar coupling. Quantum chemical calculations using density functional theory are used to obtain the <sup>13</sup>C magnetic shielding tensors for these compounds. The best agreement with experiment arises from calculations using the hybrid functional PBE0 or the double-hybrid functional PBE0-DH, along with the triple-zeta basis sets TZ2P or pc-3, respectively, and intermolecular effects modeled using large clusters of molecules with electrostatic embedding through the COSMO approach. These measurements are part of an ongoing effort to expand the catalog of accurate <sup>13</sup>C chemical shift tensor measurements, with the aim of creating a database that may be useful for benchmarking the accuracy of quantum chemical calculations, developing nuclear magnetic resonance (NMR) crystallography protocols, or aiding in applications involving machine learning or data mining. This work was conducted at the National High Magnetic Field Laboratory as part of a 2-week school for introducing undergraduate students to practical laboratory experience that will prepare them for scientific careers or postgraduate studies.</p>\",\"PeriodicalId\":18142,\"journal\":{\"name\":\"Magnetic Resonance in Chemistry\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":1.9000,\"publicationDate\":\"2024-01-17\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Magnetic Resonance in Chemistry\",\"FirstCategoryId\":\"92\",\"ListUrlMain\":\"https://onlinelibrary.wiley.com/doi/10.1002/mrc.5422\",\"RegionNum\":3,\"RegionCategory\":\"化学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q3\",\"JCRName\":\"CHEMISTRY, MULTIDISCIPLINARY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Magnetic Resonance in Chemistry","FirstCategoryId":"92","ListUrlMain":"https://onlinelibrary.wiley.com/doi/10.1002/mrc.5422","RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"CHEMISTRY, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 0
摘要
本文报告了五种氮密集化合物(即胞嘧啶、尿嘧啶、咪唑、盐酸胍和盐酸氨基胍)的 13 C 化学位移张量的主要值。虽然这些都是基本的重要化合物,但大多数都没有 13 C 化学位移张量的文献报道。化学位移张量是从 1 H→13 C 交叉偏振魔角旋转(CP/MAS)实验中获得的,这些实验是在 18.8 T 的高磁场下进行的,以抑制 14 N-13 C 残余偶极耦合的影响。利用密度泛函理论进行的量子化学计算获得了这些化合物的 13 C 磁屏蔽张量。通过使用混合函数 PBE0 或双混合函数 PBE0-DH,以及三重zeta 基集 TZ2P 或 pc-3 分别进行计算,并通过 COSMO 方法使用具有静电嵌入的大分子簇模拟分子间效应,得出了与实验最吻合的结果。这些测量结果是正在进行的扩大 13 C 化学位移张量精确测量目录工作的一部分,目的是建立一个数据库,用于为量子化学计算的准确性设定基准、开发核磁共振(NMR)晶体学协议或协助涉及机器学习或数据挖掘的应用。这项工作是在国家高磁场实验室进行的,是为期两周的学校活动的一部分,目的是向本科生介绍实验室实践经验,为他们将来从事科学工作或攻读研究生做好准备。
Carbon-13 chemical shift tensor measurements for nitrogen-dense compounds
This paper reports the principal values of the 13C chemical shift tensors for five nitrogen-dense compounds (i.e., cytosine, uracil, imidazole, guanidine hydrochloride, and aminoguanidine hydrochloride). Although these are all fundamentally important compounds, the majority do not have 13C chemical shift tensors reported in the literature. The chemical shift tensors are obtained from 1H→13C cross-polarization magic-angle spinning (CP/MAS) experiments that were conducted at a high field of 18.8 T to suppress the effects of 14N-13C residual dipolar coupling. Quantum chemical calculations using density functional theory are used to obtain the 13C magnetic shielding tensors for these compounds. The best agreement with experiment arises from calculations using the hybrid functional PBE0 or the double-hybrid functional PBE0-DH, along with the triple-zeta basis sets TZ2P or pc-3, respectively, and intermolecular effects modeled using large clusters of molecules with electrostatic embedding through the COSMO approach. These measurements are part of an ongoing effort to expand the catalog of accurate 13C chemical shift tensor measurements, with the aim of creating a database that may be useful for benchmarking the accuracy of quantum chemical calculations, developing nuclear magnetic resonance (NMR) crystallography protocols, or aiding in applications involving machine learning or data mining. This work was conducted at the National High Magnetic Field Laboratory as part of a 2-week school for introducing undergraduate students to practical laboratory experience that will prepare them for scientific careers or postgraduate studies.
期刊介绍:
MRC is devoted to the rapid publication of papers which are concerned with the development of magnetic resonance techniques, or in which the application of such techniques plays a pivotal part. Contributions from scientists working in all areas of NMR, ESR and NQR are invited, and papers describing applications in all branches of chemistry, structural biology and materials chemistry are published.
The journal is of particular interest not only to scientists working in academic research, but also those working in commercial organisations who need to keep up-to-date with the latest practical applications of magnetic resonance techniques.