Mixed-metal cluster chemistry. 35. Syntheses and structural studies of Mo 3 Ir 3 (μ 3 -O)(μ-CO) 3 (CO) 8 (η 5 -C 5 H 5 ) 3 , Mo 4 Ir 4 (μ-CO) 4 (CO) 9 (η 5 -C 5 H 5 ) 4 and Mo 3 Ir 5 (μ-CO) 3 (Cl)(CO) 6 (η 5 -C 5 H 5 ) 3 (η 5 -C 5 HMe 4 )

The reaction of Ir(CO)2(h5 -C5HMe4) with Mo2Ir2(m-CO)3(CO)7(h5 -C5H5)2 affords a complex mixture from which three structurally-characterized products were obtained following thin-layer chromatography. Mo3Ir3(m3-O)(m-CO)3(CO)8(h5 -C5H5)3 (1) is Effective Atomic Number (EAN) Rule EAN-precise and possesses an edge-bridged trigonal bipyramidal core with the face-capping oxo ligand located in a Mo2Ir2 butterfly cleft in the structure. Mo4Ir4(m-CO)4(CO)9(h5 -C5H5)4 (2) possesses four electrons less than the Polyhedral Skeletal Electron Pair Theory (PSEPT)-expected count for a capped pentagonal bipyramidal cluster with the apical atoms within bonding distance. Mo3Ir5(m-CO)3(Cl)(CO)6(h5 -C5H5)3(h5 -C5HMe4) (3) possesses a tetracapped tetrahedral core and has six electrons less than the PSEPT-predicted electron count. The core geometries exhibited by clusters 2 and 3 have previously only been observed for clusters including significant group 10 and group 11 metal content