MONOMERIC MOLYBDENUM(V) COMPLEXES .2. COMPARISON OF THE STRUCTURES OF CIS-OXOCHLOROBIS(8-MERCAPTOQUINOLINATO)MOLYBDENUM(V) AND CIS-DIOXOBIS(8-MERCAPTOQUINOLINATO)MOLYBDENUM(VI)

The crystal and molecular structures of MoOCl(tox)2 (1) and MoO2(tox)2 (2), where tox is the anion of 8-mercaptoquinoline, have been determined by x-ray crystallography. Crystal data for 1: monoclinic; space group P2l/c; a = 15.144 (2), b = 8.498 (2), c = 13.840 (3) Å β = 100.436 (15)°; Z = 4; dobsd = 1.765 (10), dcalcd = 1.774 g cm-3. Crystal data for 2: orthorhombic; space group Pbca; a = 9.038 (3), b = 14.825 (4), c = 25.210 (7) Å ; Z = 8; dobsd = 1.758 (10), dcalcd = 1.763 g cm-3. Full-matrix least-squares refinement of 1 by use of 1592 independent reflections with 3.5° 2θ ≤ 45° and I ≥ 3σ(I) gave final discrepancy indices R1 = 0.040 and R2 = 0.043. Refinement of 2 based on the 1398 unique data having 3.5° <26 ≤ 50° and I ≥ 3σ(I) converged at = 0.047 and R2 = 0.046. Compounds 1 and 2 have similar geometries. Both are monomeric with distorted octahedral geometry around each molybdenum atom. The MoO22+ grouping in 2 has the expected cis configuration with an O-Mo-O angle of 106.3 (3)°. The MoOCl2+ unit of 1 also has a cis configuration, contrary to earlier proposals, with a Cl-Mo-O angle of 103.0 (2)°. In 1 Mo-Cl = 2.342 (2) A and Mo-O = 1.716 (4) Å. The average Mo-O distance in 2 is 1.703 (12) Å. The Mo-N bonds trans to the oxo groups (2.408 (6) Å in 1 and 2.374 (9) and 2.382 (9) Å in 2) are ~0.2 Å longer than the Mo-N bond of 1 which is trans to the chlorine atom (2.210 (6) Å). The mean Mo-S distances are 2.409 (7) Å for 1 and 2.411 (1) Å for 2, respectively. The 8-mercaptoquinolinate ligands are folded along their S⋯N vectors in both compounds. © 1979, American Chemical Society. All rights reserved.