Reactivity of bis(organoamino)phosphanes with magnesium(ii) compounds

Abstract

The reactivity of three phosphanes (PhP(NHR)2 [R = t-Bu (1), Ph (2)] and PhP(NEt2)(NHDip) (3) (where Dip = 2,6-i-Pr2C6H3)) with n-Bu2Mg and MeMgBr is presented. In the case of 1, the reaction with n-Bu2Mg gave [PhP(NHt-Bu)(Nt-Bu)]Mg(n-Bu) (4) or [PhP(NHt-Bu)(Nt-Bu)]2Mg (5) depending on the stoichiometry. The treatment of 1 with MeMgBr led to the phosphinate [Ph(H)P(Nt-Bu)2]2Mg (7) as a result of both the NH→PH tautomeric transformation and elimination of MgBr2 from the non-isolable intermediate [PhP(NHt-Bu)(Nt-Bu)]MgBr(THF) (6). Phosphane 2 reacted with n-Bu2Mg in a 1:1 molar ratio resulting in the formation of {[PhP(NPh)2]2Mg(THF)2}2 (8), but the analogous reaction in a 2:1 molar ratio yielded phosphinate [Ph(H)P(NPh)2]2Mg(THF) (9). The heteroleptic compound [Ph(H)P(NPh)2]MgBr(THF)2 (10) was obtained by the reaction of 2 with MeMgBr. Finally, the reaction of 3 with n-Bu2Mg and MeMgBr produced compounds [PhP(NEt2)(NDip)]2Mg (11) and {[PhP(NEt2)(NDip)2]Mg(μ-Br)(THF)}2 (12), respectively. All products were characterized using (1)H, (13)C{(1)H} and (31)P NMR spectroscopy and, except for compounds 4 and 6, their molecular structures were determined using single-crystal X-ray diffraction analysis. In addition, a theoretical study on plausible isomers of 10 was performed to provide additional evidence for the presence of a syn- and anti-isomer in dynamic equilibrium in a solution of 10.

Divergent uranium- versus phosphorus-based reduction of Me3SiN3 with steric modification of phosphido ligands

“…The structure of 4 is a uranium(IV) centre with the metallocene ligand framework and a bis(amido)phosphane ligand in a pseudo-tetrahedral environment. [54][55][56] The uranium-nitrogen bond distances of 2.277( 4 36 The P-N bond distances are 1.734(4) and 1.741(4)Å, much longer than the 1.600(3)Å found in 3, indicative of a P-N single bond.…”

Germylenes and stannylenes stabilized within N2PE rings (E = Ge or Sn): combined experimental and theoretical study

“…Anisotropic displacement parameters are depicted at the 30% probability level. The latter complex has been investigated using the singlecrystal neutron diffraction analysis and contacts were described as C−H···Li agostic interactions involving methyl groups of the alkylaluminum moiety and Li-C bond lengths are 2.357 (19) and 2.282 (19) Å. 13 Although the Li(2)-C(3) distance of 2.498(7) Å in 5, is slightly longer, it is likely, that similar description of the Li(2)···t-Bu contact is also eligible.…”

“…The equilibrium between both species was also proven by 31 P-31 P EXSY NMR spectra similarly as done earlier for similar magnesium compounds. 19 Although a definite assignment of respective isomer to corresponding NMR data was not possible, the formation of analogous isomers was proven in similar germylenes . 6 The molecular structure of syn-12 was then unambiguously established by the single-crystal Xray diffraction analysis (Figure 7), the Cl(1) chlorine atom and the phenyl ring are placed in a syn orientation and the central PN 2 Ge ring is essentially planar.…”

“…Similar energy differences (0.47 -2.04 kcal mol -1 ) were calculated for a closely related Mg complex. 19 The NBO analysis provides Lewis-like structures which correspond to calculated electron density distributions. These structures showing also donor-acceptor interactions revealed by the NBO approach are given in Figure 12 for N 2 PE cyclic cores of selected complexes.…”

“…Similar energy differences (0.47-2.04 kcal mol −1 ) were calculated for a closely related Mg complex. 19 The NBO analysis provides Lewis-like structures which correspond to the calculated electron density distributions. These structures are provided in Fig.…”