Polymorphism of Ph₂P(CH₂Py)(NSiMe₃) and the Staudinger Reaction of Ph₂P(CH₂Py) with Hydrogenazide¹⁾

Abstract

A new polymorph of the iminophosphorane Ph2P(CH2Py)(NSiMe3), (1), is compared to a just recently published. The reaction of the starting material, the phosphane Ph2P(CH2Py) with N3SiMe3 in the presence of water gives [Ph2P(CH2Py)(NH2)][N3], (2). A comparison of the structural and NMR parameters of 2 with previously reported derivatives of 1, suggests that 2 is best described as a phosphonium salt in which the negatively charged imino nitrogen atom is protonated, according to [Ph2(CH2Py)P+—NH2][N3]—, rather than as an iminiumphosphane salt [Ph2(CH2Py)P=+NH2][N3]—.

Access to new Janus head ligands: linking sulfur diimides and phosphanes for hemilabile tripodal scorpionates

“…30 The Li2-P1 distance of 2.6425(19) A ˚is slightly longer than the average Li-P distances in Li(P-C-C N) systems (2.520 A ˚). 18 The acute N2-Li2-P1 angle of 76.79 (6) • is typical for such systems (73.10-87.35 • ). 28 It is easily possible to modify the ligand structure by introducing different substituents at the sulfur atom.…”

“…Anisotropic displacement parameters are depicted at the 50% probability level, hydrogen atoms are omitted for clarity. Selected bond lengths [A ˚] and angles [ • ]: S1-N1 1.6144(9), S1-N2 1.6351(9), S1-C9 1.8406(11), P1-C9 1.8403(11), Li1-N1 1.939(2), Li1-N2 2.398(2), Li2-P1 2.6425(19); N1-S1-N2 104.74(5), N1-S1-C9 106.38(5), N2-S1-C9 100.60(5), Li1-N2-Li2 69.23(7), N1-Li1-N2 71.93(7), N2-Li2-P1 76.79(6).…”

“…Anisotropic displacement parameters are depicted at the 50% probability level, hydrogen atoms except H1, which was freely refined, are omitted for clarity. Selected bond lengths [A ˚] and angles [ • ]: C1-P1 1.8404(13), C13-P1 1.8526(11), C13-S1 1.8092(12), N1-S1 1.6520(9), N2-S1 1.5698(10), N1-Si1 1.7421(10), N2-Si2 1.7184(10); N1-S1-N2 109.26(5), N2-S1-C13 102.99(5), N1-S1-C13 98.36(5), S1-N1-Si1 123.18(6), S1-N2-Si2 122.50(6), C7-P1-C13 102.17(7).The bond distances for P1-C1 (1.8404(13) A ˚) and P1-C13 (1.8526(11) A ˚) are similar to those of 1-5. The S1-C13 bond…”

Synthesis and Characterization of Polydentate C3 Symmetric Ligand Systems in Metal Coordination

“…Electron density studies have also shown that the nitrogen -phosphorus bond tend to be more like a single bond than a double bond with a negative partial charge at the nitrogen and a positive one at the phosphorus atom forming a typical nitrogen-ylid-compound. [28] Such small adjustments to the base ligand lead to the general tripodal iminophosphorane ligand system shown in Figure 1.3.2 that was used in this work. The ligand system itself consists of a carbon atom at the connecting backbone position which bridges the three ligand arms and is further substituted with a methyl-group.…”

“…Because of the ylid like bond between the nitrogen and the phosphorus the nitrogen gets a negative partial charge further improving its tendency to coordinate towards different metal atoms. [28] The electronic properties around the nitrogen coordination site as well as the steric demands of the whole ligand can be adjusted by employing different substituents at the phosphorus atom.…”