Hydrothermal Synthesis and Structure of a New Helical Chain Constructed from Only Molybdenum−Oxide Building Blocks

The compound [NH3(CH2)2NH2(CH2)2NH3]2[Mo9O30] was synthesized at 170 °C via hydrothermal techniques from the starting
materials of Na2MoO4·H2O, NH2(CH2)2NH(CH3)2NH2, and H2O. The
compound crystallizes in the space group C2/c of the monoclinic
system with a = 21.308(4) Å, b = 9.234(2) Å, c = 19.195(4) Å,
β = 120.27(3)°, V = 3261.9(11)Å3, Z = 4. Two novel and
symmetrically related helices coexist in the centrosymmetric solid,
in which the two kinds of helices appear in the left-handed and
right-handed enantiomorphs, respectively. This is the first example
of a helical chain structure consisting of only molybdenum−oxide
building blocks. The central axis about each helical chain is a
2-fold screw axis.