O-Pivaloyl diphenyl-seleno-phosphinate.

The title compound, C(17)H(19)O(2)PSe, was obtained in the reaction of the diphenyl-monoseleno-phosphinic acid ammonium salt with pivaloyl chloride. The P-Se bond length of 2.0769 (11) Å is normal, while the P-O bond length of 1.650 (3) Å is longer than in related O-alkyl and O-aryl derivatives. One phenyl ring is periplanar to the Se-P-C plane, while the dihedral angle between the two phenyl rings is ca 73°. The carbonyl group is in a synperiplanar position [torsion angle = 8.9 (6)°] to one of the methyl groups of the pivaloyl group. This is the first O-acyl derivative of diphenyl-monoseleno-phosphinic acid characterized by X-ray structural analysis.