The synthesis and crystal structures of the first species of monocubane type clusters [Mo3PbS4](6+) and [Mo3BiS4](7+)

The synthesis and crystal structure of two heteronuclear transition metal-main group metal cubane-like cluster compounds [Mo-3(PbI3)S-4(dtp)(3)(py)(3)] (I) and [Mo-3(BiI3)S-4(mu-OAC)(dtp)(3) .(py)].(CH3)(2)CO (II) (dtp=S2P(OC2H5)(2)(-); OAc=(OOCCH3)(-)) are reported. They resulted from the reaction of trinuclear Mo3S4(dtp)(4) . H2O with PbI3- and BiI3, respectively. Both of the molecular structures have an [Mo3MS4] core (M=Pb, Bi) but their molecular configurations are different. The electron transfer of a lone pair electrons of M metals occurs in the additive clusters I and II, thus enhancing the Mo-Mo bonding. Evidence for this is seen in the Mo-95 NMR spectrum before and after the addition reaction. Crystal data: I: triclinic, P (1) over bar, a=11.087(2), b=12.760(5), c=19.358(4) Angstrom, alpha=94.37(3), beta=92.39(2), gamma=99.46(2)degrees V=2689(2) Angstrom(3), Z=2. Least-squares refinement of 4462 reflections gave a final agreement factor of R=0.052 (Rw=0.058); II: triclinic, P (1) over bar, a=11.696(4), b=13.044(4), c=18.241 (6) Angstrom, alpha=74.90(3), beta=75.96(3), gamma=88.06(3)degrees, V=2605(3)Angstrom(3), Z=2. Least-squares refinement of 5913 reflections gave a final agreement factor of R=0.054 (Rw=0.061).