Crystal and molecular structure of diaquahydrogen(I) μ-oxo-[bis(diethyldithiocarbamato)oxomolybdate(IV)] [bis(diethyldithiocarbamato)oxomolybdenum(V)] bis{μ-oxo-bis[bis(diethyldithiocarbamato)oxomolybdenum(V)]} (1), and μ-oxo-bis[bis(diethyldithiocarbamato)oxomolybdenum(V)] (2), and the single-crystal electron spin resonance spectrum of (1)

Monoclinic crystals of form (1) belong to space group C2/c, with a = 31.340(10), b = 9.671(3),c = 38.027(10) Å, β = 110.72(5)°; the unit cell contains eight molecules of [MoO(S2CNEt2)2]2O oxo-bridged dimers (four with approximate C2 symmetry, four with crystallographic Ci symmetry), four [Mo2O3(S2CNEt2)4] - anions, and four [H5O2]+ ions. The structure has been solved with the aid of direct methods and refined by full-matrix least-squares calculations to R 0.074 using 5 508 reflections. Triclinic crystals of compound (2) belong to space group P1, with a = 8.493(3), b = 12.232(4), c = 9.775(3) Å, α = 107.52(5), β = 114.40(5), and γ = 95.82(5)°; the unit cell contains one centrosymmetric [MoO(S2CNEt2)2]2O oxo-bridged dimer. The structure has been solved by the heavy-atom method and refined by full-matrix least-squares calculations to R 0.052 using 2 340 reflections. The distorted-octahedral geometries around the molybdenum atoms in both compounds are similar; the respective mean dimensions are Mo-O(terminal) 1.686(13), 1.680(14) Å, and Mo-O(bridging) 1.875(14), 1.859(1) Å. The Mo-S lengths range from 2.436(2) to 2.694(2) Å depending upon the nature of the trans ligand. The single-crystal e.s.r. behaviour of (1) shows the presence of two distinct paramagnetic molybdenum centres in the crystal which have been assigned to the [Mo2O3(S2CNEt2)4] - ion. The principal molecular g values for these two centres are 1.976, 1.978, 1.984, and 1.978, 1.981, and 1.984.

Duke Scholars

Author Andrew T. McPhail Chemistry