Synthesis and Coordination Properties of New Bis(phosphinomethyl)pyridine N,P,P‘-Trioxides

Abstract

In a search for more hydrocarbon solvent soluble derivatives of the parent ligand, 2,6-[Ph(2)P(O)CH(2)](2)C(5)H(3)NO (1a), a series of new ligands, 2,6-[R(2)P(O)CH(2)](2)C(5)H(3)NO [R = Bz (1b); Tol (1c); Et (1d); Pr (1e); Bu (1f); Pn (1g); Hx (1h); Hp (1i); and Oct (1j)] and 2,6-[RR'P(O)CH(2)](2)C(5)H(3)NO [R = Ph, R' = Bz (2a); R = Ph, R' = Me (2b); R = Ph, R' = Hx (2c); R = Ph, R' = Oct (2d)], have been prepared by either Arbusov or Grignard substitutions on 2,6-bis(chloromethyl)pyridine followed by N-oxidation. The new ligands have been characterized by spectroscopic methods, and their coordination chemistry with selected lanthanide ions has been surveyed. Several 1:1 and 2:1 ligand/metal complexes have been isolated, and single-crystal X-ray diffraction analyses for Nd(2a)(NO(3))(3), Er(2a)(NO(3))(3), Yb(1d)(NO(3))(3), and [Nd(1c)(2)](NO(3))(3) are described. The new structural data are discussed in relation to the structures of complexes formed by 1a.

Synthesis and selected lanthanide coordination chemistry of new ((1H-pyrazol-1-yl)methyl)pyridine and -pyridine 1-oxide ligands

“…For example, the tris-heterocyclic ligand, 2,2':6',2''-terpyridine (terpy), and its numerous derivatives represent one of the most widely investigated classes of chelating ligands used in coordination chemistry [1][2][3][4][5]. Another widely studied class of tris-heterocyclic ligands is the 2,6-In recent contributions we have described several new multidentate phosphine oxide ligands based upon pyridine and pyridine N-oxide platforms including ligands of types E-I, as shown in Figure 1, and their coordination chemistry with f-element ions has proven to be interesting [11][12][13][14][15][16][17][18][19][20][21][22][23][24]. In particular, the Noxide ligands, E and G (designated as NOPO) and I (designated as NOPOPO) appear to bind more effectively with lanthanide [Ln(III)] cations than their pyridine analogs F and H, and the more flexible ligands of types G and I coordinate more strongly than ligands of type E despite the larger chelate ring ray diffraction methods.…”

Design and Development of Selective Extractants for An/Ln Separations

“…1,2 It had been further demonstrated that one derivative with R = 2-ethyl hexyl (EtHx) (1a) groups had superior extraction performance features compared to the well known CMPO extractants. Therefore, the initial objective involved development of a general scaled-up synthesis procedure for 1a and new derivatives.…”

“…During Year 1 of the project, this goal was achieved by using a Grignard-based synthesis variation used to prepare the derivative with R = Ph 1 . Sample runs that produced in excess of 25 g of 1a were accomplished and plans were made for further scale-up (not an entirely routine task in an academic research lab setting).…”

Synthesis of propionamide pyridine and pyridine n‐oxide ligands

“…The phases were separated and the organic phase dried over MgSO 4 . The solvent was then vacuum evaporated leaving a yellow oil (1.4 g) that was purified by column chromatography (silica gel 70-230 mesh, CH 2 Cl 2 :MeOH 8:1) from which a white powder (11) 2,6-Bis(N,N-dimethylpropionamide)pyridine N-oxide (12). A suspension of 11 (500 mg, 1.8 mmol), NaHCO 3 (0.31 g, 3.75 mmol) and OXONE (800 mg, 1.29 mmol) in water (2.7 mL) and MeOH (8.5 mL) was stirred under nitrogen at 45-50°C (24 h).…”