Donor Strength Determination of Buchwald-Type Phosphines.

The electronic properties of eight Buchwald-type phosphines were determined and ranked by 13 C NMR spectroscopy, highlighting the sensitivity of the Huynh electronic parameter (HEP). Furthermore, the 13 C carbene NMR signals of 19 known and new P-donor complexes in CDCl 3 (HEP values) are found to be highly correlated to those in C 6 D 6 . This enables the donor strength determination of P-donors even where the complexes are unstable or undergo rapid isomerization due to transphobia in CDCl 3 .