The Distinct Effect of theo-Carboranyl Fragment: Its Influence on the I−I Distance in R3PI2 Complexes

The shortest I−I distance in R3PI2 chemistry has been found by exploiting the electron-withdrawing capacity of the o-carboranyl fragment “RC2B10H10”. The geometry of (1-PiPr2-2-Me-1,2-C2B10H10)⋅I2 is interpreted as a molecular charge-transfer “spoke” structure (see picture). It is shown that the I−I bond in R3P-I-I can be varied in a continuous way, which poses a challenge to the concept of a bond.