Promotion of TH3 (T = Si and Ge) group transfer within a tetrel bond by a cation-π interaction.

Abstract

The possibility of the transfer of the TH3 group across a tetrel bond is considered by ab initio calculations. The TB is constructed by pairing PhTH3 (Ph = phenyl; T = Si and Ge) with bases NH3, NHCH2, and the C3N2H4 carbene. The TH3 moves toward the base but only by a small amount in these dimers. However, when a Be2+ or Mg2+ dication is placed above the phenyl ring, the tetrel bond strength is greatly magnified reaching up to nearly 100 kcal mol-1. This dication also induces a much higher degree of transfer which can be best categorized as half-transfer for the two N-bases and a near complete transfer for the carbene.