Transition-metal eight-coordination. 13. Synthesis, characterization, and crystal and molecular structure of the schiff-base chelate bis( N,N'-disalicylidene- 1,2-phenylenediamino) zirconium(IV) benzene solvate
Abstract
As part of our program to elucidate eight-coordinate complexes and their polymeric counterparts we have isolated and structurally characterized the model Schiff-base chelate bis(N,N'-disalicylidene-1,2-phenylenediamino)zirconium(IV), Zr(dsp)2, as the benzene solvate Zr(dsp)2.2.5C6H6. The synthesis involves a condensation between tetrakis(salicyla1dehydato)-zirconium(IV), Zr(sal)4, and o-phenylenediamine, a method which also allows the synthesis of analogous coordination polymers.The Zr(dsp), unit is an eight-coordinate dodecahedral species with nitrogen donors in the dodecahedral A position and oxygen donors in the B positions in accord with theoretical predictions. The chelating ligands span the mam edges. The Zr-0 bonds average 2.10 A, which is appreciably shorter than the Zr-N distance of 2.43 A. The donor atoms are in an almost perfect dodecahedral array with the trapezoidal planes intersecting at 89.2 degrees, even though the chelating ligands are quite puckered from these planes. The Zr(dsp),.2.5C6H6 solvate crystallizes in the space group Pi with Z = 2, a = 13.037(4) A, b = 13.669 (6) A, c = 14.500 (2) A, a = 98.81 (2)degrees, p = 116.47 (2) degrees, and y = 92.78 (3) degrees.