92284-90-7Relevant academic research and scientific papers
Rhenium-catalyzed amination of alcohols by hydrogen transfer process
Abdukader, Ablimit,Jin, Hongming,Cheng, Yixiang,Zhu, Chengjian
supporting information, p. 4172 - 4174 (2014/07/22)
The rhenium heptahydride complex [ReH7(PCy3) 2] was found to be an effective homogeneous catalyst for amination of various alcohols through hydrogen transfer mechanism. Under carbon monoxide atmosphere, a variety of primary and secondary alcohols could directly undergo the CN coupling process.
Intra- and inter-ion-pair protonic - Hydridic bonding in polyhydridobis(phosphine)rhenates
Abdur-Rashid,Lough,Morris
, p. 964 - 976 (2007/10/03)
The hexahydridobis(phosphine)rhenate anions, [ReH6(PR3)2]- (PR3 = PCy3 ,P-i-Pr3, PPh3, PMe3) were generated by potassium hydride deprotonation of the neutral heptahydride conjugate acids (ReH7(PR3)2), isolated as their [K(18-crown-6)]+ and [K(1,10-diaza-18-crown-6)]+ salts, and characterized by NMR and IR spectroscopy and elemental analyses. Structures from single crystal X-ray diffraction were obtained for the [K(1,10-diaza-18-crown-6)]+ salts and these indicate the presence of short protonic - hydridic bonds involving the hydrides of the anions and the proton donor NH moieties of the cations. The structure of [K(1,10-diaza-18-crown-6)][ReH6(P-i-Pr3)2] adopts a one-dimensional zigzag chain with alternating cations and anions connected and held together by inter-ion N-H···Hx-Re interactions (x = 1 or 2). Short distances between the NH protons of the cations and hydrides of the anion ranging from 1.6 to 1.9 A are estimated for this complex. A different kind of chain structure is observed for [K(1,10-diaza-18-crown-6)][ ReH6(PMe3)2] in which the combined effects of inter-ion protonic - hydridic bonding (N-H···Hx-Re) and inter-ion electrostatic interactions (ReHx-···K+ ···Hx-Re), result in one-dimensional networks of alternating cations and anions, with the metals and hydrides occupying the interior and the organic moieties of the phosphine ligands and crown ether lining the exterior of cylindrical supramolecular assemblies. A combination of intra- and inter-ion protonic-hydridic and intra-ion-pair electrostatic interactions in [K(1,10-diaza-18-crown-6)][ReH6(PPh3)2] result in the formation of discrete two-dimensional {[K(1,10-diaza-18-crown-6)][ReH6(PPh3)2]} 4 tetramers. The PCy3 salt is disordered but appears to consist of isolated 1:1 ion pairs containing strong intra-ion-pair NH···HRe bonding. The solid-state IR spectra of the [K(1,10-diaza-18-crown-6)]+ salts show low-frequency shifts for the NH bands relative to [K(1,10-diaza-18-crown-6)][BPh4], and perturbed Re-H bands relative to those in the [K(18-crown-6)]+ salts. The magnitude of δvnNH is related to the basicity of the anion as indicated by the pKαTHF of the conjugate acid form (ReH7(PR3)2), which increases as PPh3 3 3 3. Solution 1H NMR, NOE, and T1 relaxation measurements of [K(1,10-diaza-18-crown-6)][ReH6(PPh3)2] indicate that these interactions also persist in toluene solutions of this compound.
Mechanistic Features of C-H Activation by ReH72
Zeiher, E. H. Kelle,DeWit, David G.,Caulton, Kenneth G.
, p. 7006 - 7011 (2007/10/02)
The synthesis and characterization of ReH7(PCy3)2 (Cy=cyclohexyl) is reported.This compound is thermally resistant to the dimerization reaction exhibited by other ReH7(PR3)2 compounds, which allows mechanistic features of C-H activation to be studied.Thus, in the temperature range 60-80 deg C, ReH7(PCy3)2 exchanges hydrogen with deuteriobenzene.Deuterium is incorporated into the complex not only as hydride ligands but also selectively at the C2 and C3 carbons of all cyclohexyl rings.Only one of the two methylene hydrogens at each of these carbons is exchangeable.It is also shown that exchange at the two adjacent carbons does not proceed by concerted dehydrogenation via a cyclohexenyl intermediate; the rate of deuterium incorporation at C3 differs from that at C2.On the basis of observation of exchange with D2, and also kinetic studies of the reaction of ReH7(PCy3)2 with phosphine and olefinic nucleophiles, all of the thermal reactions observed here are concluded to arise from the reductive elimination transient ReH5(PCy3)2.
