EFFECTS OF CRYSTAL PACKING ON THE COORDINATION GEOMETRY OF 8-COORDINATE METAL-CHELATES - CRYSTAL AND MOLECULAR-STRUCTURE OF TETRAKIS(1,3-DIPHENYL-1,3-PROPANEDIONATO)ZIRCONIUM(IV)

The crystal and molecular structure of tetrakis(l, 3-diphenyl-l, 3-propanedionato)zirconium(IV), Zr(bzbz)4, has been determined by single-crystal X-ray diffraction and has been refined anisotropically by least-squares techniques to R1 = 0.080 and R2= 0.072 by using 5168 independent diffractometer-recorded reflections having 2θ(Cu K±) < 110.03° and |F0| > 2θ(|F0|).The compound crystallizes in the monoclinic space group P2Jc with four molecules in a unit cell of dimensions a = 25.241(5), b = 10.324 (1), and c = 19.395 (4) Å β = 101.72 (1)° (pobsd = 1.31, pcalcd = 1.321 g cm-3). The crystal contains discreteeight-coordinate molecules in which the bidentate dibenzoylmethanate ligands span the s edges of a slightly distorted square antiprism to give the ssss-D2 stereoisomer. Distortions are in the direction of the bicapped trigonal-prismatic h1h1P2P2-C2 stereoisomer. The distortions, presumably due to the effects of crystal packing, are compared with the some what different distortions in the analogous Zr(acac)4 complex. The Zr-O bonds in Zr(bzbz)4 fall into two symmetry-inequivalent sets: Zr-O(outer) = 2.153 Å and Zr-O(inner) = 2.192 Å. The C302 portions of the chelate rings are planar, but the rings are folded (by 21.7 ± 2.2°) about the edges (O—O) of the square antiprism; all four rings are bent away from the quasi-8 axis of the antiprism. The phenyl groups are twisted out of the C3O2 planes by angles that vary from 17.3 to 41.9°. © 1979, American Chemical Society. All rights reserved.