American Chemical Society
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Coordination and Rearrangement of Organic Chalcogenides on a Rhodium−Rhodium Bond:  Reactions with Strained-Ring Cyclic Thioethers and with Selenium and Tellurium Ligands

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journal contribution
posted on 1999-11-17, 00:00 authored by Michael P. Devery, Ron S. Dickson, Brian W. Skelton, Allan H. White
When the cyclic thioethers L = and were added to [(η5-C5H5)2Rh2(μ-CO)(μ-η22-CF3C2CF3)] (1), the coordinative addition products [(η5-C5H5)2Rh2(CO)(μ-η11-CF3C2CF3)L] (2ac) were formed reversibly. When it is left in solution in the presence of excess ligand, the propylene sulfide complex 2b (L = transforms to the bridging sulfido complex [(η5-C5H5)2Rh2{μ-η112-C(O)C(CF3)C(CF3)}(μ-S)] (3a). A similar reaction occurred, but to a lesser extent, with the trimethylene sulfide complex 2a (L = Comparable decompositions do not occur with the tetrahydrothiophene complex 2a (L = The dimethylselenane complex [(η5-C5H5)2Rh2(CO)(μ-η11-CF3C2CF3)(SeMe2)] (4a) was formed reversibly when SeMe2 was added to solutions of 1. The reactions of 1 with the organotelluranes L‘ = TeMe2 and TeEt2 gave solid addition products [(η5-C5H5)2Rh2(CO)(μ-η11-CF3C2CF3)L‘] (4b,c), which remained intact when dissolved in polar solvents. No rearrangement products were formed when solutions of the tellurane addition products were kept for several days. The bridging sulfido complex 3a and the analogous complexes [(η5-C5H5)2Rh2{μ-η112-C(O)C(CF3)C(CF3)}(μ-E)] (3b, E = Se; 3c, E = Te) were obtained from the direct reaction between E and the complex 1. Addition of the cyclic tellurane to 1 gave (6), which underwent rapid intramolecular ligand scrambling in solution. The crystal and molecular structure of 6 was determined by X-ray crystallography.