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)

Abstract

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 C_i 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 P, 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.