Synthesis and Crystal Structure of an Open Capsule-Type Octanuclear Heterometallic Sulfide Cluster with a Linked Incomplete Double Cubane Framework without an Intramolecular Inversion Center

An open capsule-type octanuclear heterometallic sulfide cluster without an intramolecular inversion
center [Ru(η6-C6Me6){P(OMe)3}{MoO(μ3-S)3}(CuI)2]2 (5) has been synthesized for the first time by stepwise
connection of three mononuclear building blocks, i.e., (i) [RuCl2(η6-C6Me6){P(OMe)3}] (1a) as an octahedral
terminal building block to control the direction of cluster expansion, (ii) [MoOS3]2- as a tetrahedral polydentate
building block owing to the strong coordination ability of the S atoms, and (iii) a CuI building block to form
a trigonal planar (μ-S)2CuI unit or to form a linkage unit of two incomplete cubane-type octanuclear
frameworks. The stepwise connection was made in the following order:  [RuCl2(η6-C6Me6){P(OMe)3}] (1a,
mononuclear) → [Ru(η6-C6Me6){P(OMe)3}{MoOS(μ2-S)2}] (2a, dinuclear) → [Ru(η6-C6Me6){P(OMe)3}{MoO(μ2-S)2(μ3-S)}CuI] (3a, butterfly-type trinuclear) → [Ru(η6-C6Me6){P(OMe)3}{MoO(μ3-S)3}(CuI)2]2 (5). When
P(OMe)3 was replaced by P(OEt)3, which is more bulky than P(OMe)3, in the starting ruthenium building
block [RuCl2(η6-C6Me6){P(OEt)3}] (1b, mononuclear), only the tetranuclear incomplete single cubane cluster
[Ru(η6-C6Me6){P(OEt)3}{MoO(μ3-S)3}(CuI)2] (6) was generated, owing to the steric effect of P(OEt)3.