Preparation and Structure of Sterically Protected Diethynylphosphines and Dibutadiynylphosphines

Sterically protected diethynyl(2,4,6-tri-t-butylphenyl)phosphines and (2,4,6-tri-t-butylphenyl)bis(4-trimethylsilyl-1,3-butadiynyl)phosphine were prepared and their structures were analyzed by X-ray crystallography. The aromatic rings in these molecules are distorted to boat or more likely envelope forms in the crystals. Large distortion in the –P–C≡C– moieties was also observed.