The First Molybdenum Oxo‐iodide Cluster – [Mo₄OI₁₂]^2–

Abstract

Reaction of Mo(CO) 6 with Bu 4 NI and I 2 in diglyme yielded a new butterfly Mo III cluster [Mo 4 OI 12 ] 2-. The structure of tetraphenylphosphonium salt was determined by X-ray single crystal diffraction. Ph 4 P + and Bu 4 N + salts were further characterized by elemental analy-* Dr. M. Mikhaylov 438 sis, mass spectrometry, energy-dispersive X-ray (EDX), IR, Raman, and UV/Vis spectroscopy and CVA studies. The cluster anion has a butterfly array of molybdenum atoms and can be represented as [Mo 4 (μ 4 -O)(μ 3 -I) 2 (μ 2 -I 4 )I 6 ] 2-.

First Pentanuclear Molybdenum Iodide Cluster (Bu4N)[Mo5OI13]: Synthesis and Structure

“…On the one hand, no formation of molybdenum iodide clusters of lower nuclearity was observed at Т > 300°С. On the other hand, it is known that the tetranuclear molybdenum cluster [Mo 4 OI 12 ] 2will be the final product if another molybdenum source (Mo(CO) 6 ) would be used and the reaction with iodine would be carried out at a substantially lower temperature (110°С) in diglyme [15]. An increase in nuclearity in the series [Mo 4 OI 12 ] 2--[Mo 5 OI 13 ] --[Mo 6 I 14 ] 2is parallel with a decrease in the oxidation state of molybdenum (+3.0, +2.8, and +2.0, respectively).…”

“…This indicates that the replacement of the {MoI}fragment (d 0 , 6e) by the isoelectronic oxygen atom (s 2 p 4 , 6e) does not substantially affect the bonding cluster skeletal orbitals responsible for the formation of metal-metal bonds. In the oxoiodide cluster (Bu 4 N) 2 [Mo 4 OI 12 ] with the "butterfly" structure, the Mo-Mo distances are not equivalent and range from 2.65 Å (shortest bond in the "butterfly" structure {Mo 4 }) to 2.73 Å (other Mo-Mo bonds), and the Mo-O distances also differ: 2.07 and 2.15 Å [15]. The comparable (with those found in I) metal-metal distances belong to the tungsten clusters (W-W distance in [PrN] 2 [W 5 I 13 ] is 2.64 Å [9], while in [W 6 I 14 ] 2this distance is somewhat longer: 2.67 Å [6]).…”