(Carbonyl-1κC)bis[2,3(η5)-cyclopentadienyl][μ3-(S-methyl trithiocarbonato)methylidyne-1:2:3κ4 C,S′′:C:C](triphenylphosphine-1κP)(μ3-sulfido-1:2:3κ3 S)dicobalt(II)iron(II) trifluoromethanesulfonate

The asymmetric unit of the title compound, [FeCo2(C5H5)2(C3H3S3)S(C18H15P)(CO)]CF3SO3, consists of a triangular irondicobalt cluster cation and a trifluoromethanesulfonate anion. In the cation, the FeCo2 triangle is symmetrically capped on one face by an S atom and on the other by a C atom linked to a methyl trithiocarbonate residue that bridges the Fe—C bond. Each Co atom carries a cyclopentadienyl ligand while the Fe atom coordinates to one carbonyl and one triphenylphosphine ligand. In the crystal structure, the cation is linked to the anion by a number of weak non-classical C—H⋯O and C—H⋯F hydrogen bonds and weak S⋯O (3.317 Å) and S⋯F (3.198 Å) interactions. The structure is further stabilized by additional intermolecular C—H⋯O, C—H⋯F and O⋯O (2.942 Å) contacts, together with an unusual S⋯π(Cp) interaction (S⋯centroid distance = 3.385 Å), generating an extended network.

The asymmetric unit of the title compound, [FeCo 2 (C 5 H 5 ) 2 -(C 3 H 3 S 3 )S(C 18 H 15 P)(CO)]CF 3 SO 3 , consists of a triangular irondicobalt cluster cation and a trifluoromethanesulfonate anion. In the cation, the FeCo 2 triangle is symmetrically capped on one face by an S atom and on the other by a C atom linked to a methyl trithiocarbonate residue that bridges the Fe-C bond. Each Co atom carries a cyclopentadienyl ligand while the Fe atom coordinates to one carbonyl and one triphenylphosphine ligand. In the crystal structure, the cation is linked to the anion by a number of weak non-classical C-HÁ Á ÁO and C-HÁ Á ÁF hydrogen bonds and weak SÁ Á ÁO (3.317 Å ) and SÁ Á ÁF (3.198 Å ) interactions. The structure is further stabilized by additional intermolecular C-HÁ Á ÁO, C-HÁ Á ÁF and OÁ Á ÁO (2.942 Å ) contacts, together with an unusual SÁ Á Á(Cp) interaction (SÁ Á Ácentroid distance = 3.385 Å ), generating an extended network.
The structure is further stabilized by additional intermolecular C-H···O, C-H···F and O···O contacts which generate an extended network ( Table 2). Pairs of cluster cations, interleave with trifluoromethylsulphonate cations to form interlinked columns down the c axis (Fig. 3).

S2. Experimental
The title compound was prepared from the room temperature reaction of methyl trifluoromethanesulfonate with [{Co(η 5 - Manning et al. (2003), with X-ray quality crystals grown from dichloromethane layered with methanol.

S3. Refinement
The crystals were small and weakly diffracting and little useable data were obtained beyond θ = 24°. All H-atoms bound to carbon were refined using a riding model with d(C-H) = 0.95 Å, U iso =1.2U eq (C) for aromatic and 0.98 Å, U iso = 1.5U eq (C) for CH 3 H atoms.

Figure 1
The asymmetric unit of (I), with 50% probability displacement ellipsoids for non-H atoms.  The unusual S···π(Cp) interaction (dotted line) in (I). The red circle represents the centroid of the C21···C25 cyclopentadiene ring.

Figure 3
Crystal packing of (I) viewed down the c axis.