CRYSTAL AND MOLECULAR STRUCTURES OF ZINC AND CADMIUM O,O-DIISOPROPYLPHOSPHORODITHIOATES

The crystal and molecular structures of zinc, O-O diisopropylphosphorodithioate and isomorphous cadmium, O-O diisopropylphosphorodithioate have been solved by single-crystal X-ray diffraction techniques. Three-dimensional scintillation counter data were used to refine the structures by full-matrix least-squares procedures to final conventional R factors of 0.088 and 0.083, respectively (based on F). The crystals are monoclinic, space group C2/c (no. 15), with a = 10.934 ± 0.008 Å, b = 17.098 ± 0.006 Å, c = 25.587 ± 0.012 Å, β = 99.23 ± 0.04°, dobsd = 1.37 ± 0.02 g/cm3, and (Wed = 1.384 ± 0.002 g/cm3 for the zinc complex and a = 10.964 ± 0.006 Å, b = 16.906 ± 0.008 Å, c = 26.490 ± 0.008 Å, β = 99.91 ± 0.02°, dobsd = 1.46 ± 0.02 g/cm3, and dcalcd = 1.480 ± 0.002 g/cm3 for the cadmium complex. Both complexes are binuclear. These dimers, four per unit cell of formula M2[(i-C3H7O)2PS2]4, where = Zn or Cd, lie on the twofold axes of the unit cell. Each metal atom is coordinated with four sulfur atoms in a distorted tetrahedral environment. The metal-sulfur bonds range in length from 2.302 (6) to 2.409 (5)Å in the zinc complex and from 2.486 (7) to 2.590 (8) Å in the cadmium complex. The metal … metal approach within each dimer is 4.108 (5) and 4.059 (4) Å, respectively. Associated with each metal atom are two (i-C3H7O)2PS2 groups, one which functions as an intrachelating group bound wholly to one metal atom and the other which functions as a bridging, or interchelating, group linking two monomeric molecules together to form the dimer; the result is a molecule consisting of two four-membered rings joined to a central eight-membered ring through the metal atoms. The inter- and intrachelating groups deviate onty slightly from planarity with the metal atoms and the central eight-membered ring possesses the “cradle” configuration. The phosphorus-sulfur bonds average 1.970 (11) and 1.965 (8) Å in length in the zinc and cadmium structures, respectively; the phosphorus-oxygen bonds average 1.58 (2) Å in length. The molecules pack in the crystals to form layers or sheets and, like the molecules within these sheets, are held together by van der Waals forces. © 1969, American Chemical Society. All rights reserved.