68773-03-5Relevant academic research and scientific papers
An Improved Synthesis of Me4PCP and DMPE
Lekich, Travis T.,Askelson, Phoebe G.,Burdick, Ryan K.,Heinekey, D. Michael
, p. 211 - 213 (2018)
We present a new synthetic method for the bis(dimethyl)phosphines Me4PCP (C6H4-2,6-(CH2P(CH3)2)2) and DMPE ((CH3)2PCH2CH2P(CH3)2) that starts from an aminophosphine, Et2NPMe2. Two equivalents of Et2NPMe2 react with the corresponding bis(alkyl bromide) to afford an oxygen-and moisture-stable aminophosphonium salt. NaAlH4 selectively reduces the aminophosphonium salt to the desired phosphine. Each step is high yielding and requires minimal purification.
Transfer-dehydrogenation of alkanes catalyzed by rhodium(I) phosphine complexes
Wang, Kun,Goldman, Martin E.,Emge, Thomas J.,Goldman, Alan S.
, p. 55 - 68 (2007/10/03)
Complexes of the form Rh(PMe3)2ClL' (L' = CO or trisubstituted phosphine) and [Rh(PMe3)2Cl]2 have previously been reported to catalyze the transfer-dehydrogenation of alkanes, using olefinic hydrogen acceptors under a dihydrogen atmosphere. Such complexes are herein reported to effect transfer-dehydrogenation in the absence of H2 but with much lower rates and total catalytic turnovers, even at much greater temperatures. Analogs with halides other than chloride (Br, I), or with pseudo-halides (OCN, N3), are found to exhibit generally similar behavior: high catalytic activity under H2 and measurable but much lower activity in the absence of H2. Thermolysis (under argon) of complexes [RhL2Cl]n (n = 1, 2; L is a phosphine bulkier than PMe3) in cyclooctane in the absence of hydrogen acceptors yielded cyclooctene. However, transfer-dehydrogenation was plagued by ligand decomposition. Under a hydrogen atmosphere complexes containing ligands much bulkier than PMe3 do not effect dehydrogenation. Complexes with tridentate ligands, η3-PXP)RhL' (PXP = (Me2PCH2Me2Si)2N, Me2PCH2(2,6-C6H3)CH2PMe2; L' = CO, C2H4), were also found to catalyze thermal or photochemical dehydrogenation of cyclooctane with limited reactivity. The structure of [Rh(PMe3)2Cl]2 was determined by single-crystal diffraction. The Rh(μ-Cl)2Rh bridge of 1 is folded like that of [Rh(CO)2Cl]2, unlike that of the planar PPh3 and PiPr3 analogs.
