112680-67-8Relevant academic research and scientific papers
Synthesis and characterization of sulfur-capped trinuclear group 6B metal clusters
Darensbourg, Donald J.,Zalewski, David J.
, p. 1598 - 1600 (1984)
The sulfur-capped trinuclear chromium carbonyl cluster S[Cr(CO)4]32- has been synthesized and shown to arise via carbon monoxide loss from the CO-saturated S[Cr(CO)5]32- species. The carbon monoxide ligands display complete stereochemical nonrigidity at ambient temperature. In a low-energy process that occurs below -60°C the bridging carbon monoxide groups and the set of terminal CO groups that are cis to the capping sulfide moiety undergo fast exchange when compared to their chemical shift differences (1218 Hz at 50.3 MHz). A subsequent, higher energy exchange process of these carbon monoxide ligands with the remaining terminal carbonyl sites (those trans to the sulfide cap) occurs at temperatures greater than -20°C. Addition of Cr(13CO)5THF to the S[Cr(CO)4]32- trimer results in formation of (CO)5CrS[Cr(CO)4]32-, where the 13CO ligands are shown to be statistically distributed throughout the tetrameric species.
Cluster synthesis via aggregation: Synthesis and solution and solid-state characterization of sulfur-capped group 6 metal carbonyl clusters
Darensbourg, Donald J.,Zalewski, David J.,Sanchez, Kathryn M.,Delord, Terry
, p. 821 - 829 (2008/10/08)
The trinuclear clusters [PPN]2[M3(CO)12S] (M = Cr, Mo, W) have been prepared by a stepwise aggregation of [M(CO)5] fragments about a sulfur atom template, with subsequent loss of three carbonyl ligands concomitant with the formation of three metal-metal bonds. The stepwise assembly process allows for the synthesis of the mixed-metal clusters [PPN]2[Cr2W(CO)12S], [PPN]2[Mo2W(CO)12S], and [PPN]2[CrMoW(CO)12S]. These compounds have been characterized by infrared and 13C NMR spectroscopies, and X-ray crystal structures of the Cr3, Mo3, and Mo2W clusters have been determined. [PPN]2[Cr3(CO)12S]: space group P21/c, a = 25.732 (6) ?, b = 14.255 (5) ?, c = 21.689 (4) ?, β = 96.16 (3)°, V = 7909.8 ?3, Z = 4. [PPN]2-[Mo3(CO)12S]: space group P21/c, a = 25.953 (4) ?, b = 14.329 (2) ?, c = 21.830 (5) ?, β = 96.26 (2)°, V = 8069.2 ?3, Z = 4. [PPN]2[Mo2W(CO)12S]: space group P21/c, a = 25.912 (6) ?, b = 14.275 (3) ?, c = 21.871 (3) ?, β = 96.23 (2)°, V = 8042.0 ?3, Z = 4. The trinuclear clusters can add a fourth [M(CO)5] unit to produce the tetranuclear derivatives [PPN]2-[M4(CO)17S]. In solution, the carbonyl ligands of both the tri- and tetranuclear clusters are extremely fluxional. Temperatures as low as -110°C must be achieved to freeze out the various processes.
