{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,6]],"date-time":"2026-06-06T14:52:21Z","timestamp":1780757541120,"version":"3.54.1"},"reference-count":65,"publisher":"MDPI AG","issue":"23","license":[{"start":{"date-parts":[[2023,11,23]],"date-time":"2023-11-23T00:00:00Z","timestamp":1700697600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Molecules"],"abstract":"<jats:p>The scopes and limitations of theoretical methods for estimating various NMR metrics of NHCs are considered on a wide range of model NHCs and their derivatives, using a number of computational approximations. On the whole, the most reliable, from the point of view of predictability and insusceptibility to additional effects, are 31P\/13C NMR shifts of NHC\u2013phosphinidene adducts and 13C CSs of carbenes themselves. The method based on the analysis of 77Se CS NHC\u2013selenoureas has some limitations since the observed NMR parameters can also be modulated by exchange effects due to their formation with non-classical hydrogen bonds. As for HEP, since the delicate balance of electron distribution between Pd and two carbon centers can nonlinearly affect relativistic spin\u2013orbit effects, the accuracy of the estimation of this metric may still be limited. 13C CSs of NHC\u2013azolium salts do not seem to be reliable, since the observed values are strongly influenced by the effects of the exchange between different forms with counterions, which are difficult to estimate correctly.<\/jats:p>","DOI":"10.3390\/molecules28237729","type":"journal-article","created":{"date-parts":[[2023,11,23]],"date-time":"2023-11-23T03:45:56Z","timestamp":1700711156000},"page":"7729","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":4,"title":["NMR \u201cFinger Prints\u201d of N-Heterocyclic Carbenes, DFT Analysis: Scopes and Limitations"],"prefix":"10.3390","volume":"28","author":[{"given":"Svetlana A.","family":"Kondrashova","sequence":"first","affiliation":[{"name":"Arbuzov Institute of Organic and Physical Chemistry, FRC Kazan Scientific Center of RAS, 420088 Kazan, Russia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4757-6157","authenticated-orcid":false,"given":"Shamil K.","family":"Latypov","sequence":"additional","affiliation":[{"name":"Arbuzov Institute of Organic and Physical Chemistry, FRC Kazan Scientific Center of RAS, 420088 Kazan, Russia"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2023,11,23]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"4986","DOI":"10.1021\/acs.chemrev.8b00514","article-title":"N-heterocyclic carbenes in materials chemistry","volume":"119","author":"Smith","year":"2019","journal-title":"Chem. 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