Crystal and molecular structure of bis[(1,2-dihapto-3,5-dimethyl-pyrazolido)-?-allylpalladium(II)

Abstract

The crystal and molecular structure of bis[(1,2-dihapto-3,5-dimethylpyrazolido)-π-allylpalladium(II)], C16H24N4Pd2, has been determined by X-ray diffraction techniques. The crystals are monoclinic,P21/c (No. 14), witha = 8.752(1),b = 18.932(2),c = 11.780(3) A, and β = 109.78(1) °. The observed crystal density (1.746 g cm−3) agrees well with that calculated on the basis of four molecules per unit cell (1.754 g cm−3). The structure has been refined by full-matrix least-squares techniques to a finalR1 value of 0.045 (R2 = 0.056) for 2974 unique reflections withInet⩾7 counts sec−1. The Pd2N4 ring is in a boat conformation in which the two palladium atoms are 1.113 and 1.064 A out of the plane defined by the four nitrogen atoms. The Pd-C bond distances to the terminal atoms of the π-allyl groups (2.12 A) are longer than those to the central carbon atoms (2.06 A). The molecule possesses approximatemm2 (C2v) symmetry.