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Basicity of Nucleophilic Carbenes in Aqueous and Nonaqueous Solvents - Theoretical Predictions
journal contributionposted on 2023-05-16, 15:38 authored by Magill, AM, Cavell, KJ, Brian YatesBrian Yates
The complete basis set method CBS-QB3 was used in conjunction with the CPCM solvation model to predict both the absolute and relative pKa's of 12 nucleophilic carbenes in dimethyl sulfoxide (DMSO), acetonitrile (MeCN), and water. Average absolute pKa values in DMSO ranged from 14.4 Â± 0.16 for 3-methylthiazol-2-ylidene (12) to 27.9 Â± 0.23 in the case of bis(dimethylamino)carbene (11), while values in MeCN were determined to be between 25.7 Â± 0.16 (12) and 39.1 Â± 0.25 (11). Relative pK a calculations yielded similar results. Calculations in aqueous solution gave pKa's between 21.2 Â± 0.2 (12) and 34.0 Â± 0.3 (11). Excellent agreement between calculated and experimental pK a's was obtained for the few cases where experimental numbers are available, confirming that this theoretical approach may be used to calculate highly accurate pKa values.
Publication titleJournal of the American Chemical Society
Department/SchoolSchool of Natural Sciences
PublisherAmerican Chemical Society
Place of publicationWashington