Multidimensional Lewis Acidity: A Consistent Data Set of Chloride, Hydride, Methide, Water and Ammonia Affinities for 183 p‐Block Element Lewis Acids

Abstract

The computed fluoride ion affinity (FIA) is a widely applied descriptor to gauge Lewis acidity. Like every other single‐parameter Lewis acidity scale, the FIA metric suffers from the one‐dimensionality, that prohibits addressing Lewis acidity by the multidimensionality it inherently requires (i. e., reference Lewis base dependency). However, a systematic screening of computed affinities other than the FIA is much less developed. Herein, we extended our CCSD(T)/CBS benchmark of different density functionals and the DLPNO‐CCSD(T) method for chloride (CIA), methide (MIA), hydride (HIA), water (WA), and ammonia (AA) affinities. The best performing methods are subsequently applied to yield nearly 800 affinities for 183 p‐block element compounds of group 13–16 with an estimated accuracy of <10 kJ mol−1. The study‘s output serves as a consistent library for qualitative analyses and a training set for future statistical approaches. A first holistic correlation analysis underscores the need for a multidimensional description of Lewis acidity.

Lewis Superacidic Heavy Pnictaalkene Cations: Comparative Assessment of Carbodicarbene-Stibenium and Carbodicarbene-Bismuthenium Ions

“…Enhancing the Lewis acidity at the pnictogen center typically enhances the reactivity of pnictenium ions. 51 The Lewis acidity of p-block compounds has been evaluated using a variety of methods, including FIA, 52,53 hydride ion affinity, 54 and the GB method. 55−57 The GB method is an experimental technique that measures the change in the 31 P NMR chemical shift of triethylphosphine oxide (O�PEt 3 ) after it is added to the sample of interest, which translates to an AN using the following formula AN = 2.21 × [δ( 31 P NMR) sample − 41.0].…”

“…Enhancing the Lewis acidity at the pnictogen center typically enhances the reactivity of pnictenium ions . The Lewis acidity of p-block compounds has been evaluated using a variety of methods, including FIA, , hydride ion affinity, and the GB method. − The GB method is an experimental technique that measures the change in the 31 P NMR chemical shift of triethylphosphine oxide (OPEt 3 ) after it is added to the sample of interest, which translates to an AN using the following formula AN = 2.21 × [δ­( 31 P NMR) sample – 41.0]. , Comparative methods using softer bases (e.g., S = PMe 3 , Se = PMe 3 ) have also been used to evaluate the Lewis acidity of heavy group 15 complexes. , Greb and Erdmann highlighted that the GB method is most reliable as a comparative tool for complexes that contain the same central elements and comparable ligands …”

Theoretical calculation-based ammonia affinity: A unified method for evaluating Lewis acidity of organoboronic acid derivatives

“…35 Therefore, our attention was focused on global Lewis acidity (gLA) of organoboronic acid derivatives; gLA is evaluated by various affinity scales including fluoride ion affinity (FIA) and ammonia affinity (AA). 32,38 Owing to difficulties in calculating accurate…”

Diiminium Nucleophile Adducts are Stable and Convenient Lewis Superacids

“…The nucleophile-stabilised DINu were computed to show exceptionally high FIAs (907-982 kJ mol −1 ) and HIAs (1079-1243 kJ mol −1 ). All of them surpass the HIA of the trimethylsilyl cation, and DIPy surpassed even its FIA (Figure 3D) (5,44). The meta-hexafluorinated trityl cation as one of the strongest isolable tritylbased carbocations, in comparison, has an HIA of 960 kJ mol −1 (16).…”

“…To quantitatively determine the hard and soft Lewis acidities of the DINu salts, we computed gas phase fluoride and hydride ion affinities (FIA, HIA) according to Greb's and Krossing's scheme (42)(43)(44)(45). The nucleophile-stabilised DINu were computed to show exceptionally high FIAs (907-982 kJ mol −1 ) and HIAs (1079-1243 kJ mol −1 ).…”