Abstract
Structure of the title compound was determined by the X-ray analysis. The sulfur atom intramolecularly coordinates to the boron atom with a distance of 2.071 Å and the relation between the butyl group at the benzylic position and the S-ethyl group is nearly anti. The observed dynamic behavior in the compound is discussed on the basis of the structure and the results of some NMR experiments. Other structural features and the tetrahedral character of the boron atom are also reported.