302595-07-9Relevant academic research and scientific papers
Further studies on the substitutional behavior of 1,2-Mo2Br2(CH2SiMe3)4. Alkyl, amide, phosphide, alkoxide, and thiolate for bromide exchange and isomerizations of 1,1- and 1,2-Mo2X2(CH2SiMe3)4 compounds
Chisholm, Malcolm H.,Click, Damon R.,Huffman, John C.
, p. 3916 - 3924 (2008/10/08)
Reactions involving 1,2-Mo2Br2(CH2SiMe3)4 and each of LiNMe2 and HNMe2 in hexane at -50 °C proceed to give 1,1′-Mo2(NMe2)BrR4, where R = CH2SiMe3, as the first product of Br for amide exchange at the Mo26+ center. Further substitution in reactions with LiNMe2 gives 1,1-Mo2(NMe2)2R4, but with HNMe2 the 1,2-Mo2(NMe2)2R4 isomer is formed. These two do not interconvert thermally (>100 °C) and undergo aminolysis (HNMe2-d6) and alcoholysis (tBuOH) with retention of regiochemistry. 1,1- to 1,2-isomerization of Mo2(NMe2)2R4 is catalyzed by the presence of Me2NH2Br. The mechanisms of these metathetic reactions are discussed in terms of plausible pathways that may promote alkyl group migration across the Mo triple bond Mo bond. Further studies of the bromide substitution by alkyl, aryl, alkoxide, thiolate, and phosphide ligands are described for 1,1′-Mo2(NMe2)BrR4 and 1,2-Mo2Br2R4. The new compounds of formula Mo2(NMe2)YR4 (Y = CH2SiMe3, Ph, OtBu, OiPr, StBu, PPh2, and Br) and Mo2(StBu)2R4 have been characterized by variable-temperature 1H and 13C{1H} NMR spectroscopy and mass spectrometry and for Y = PPh2 by single-crystal X-ray crystallography.
