Synthesis, Characterization, and Coordination Chemistry of a New Geometrically Hindered Trifunctional Ligand, 4,5-Bis(diphenylphosphino)-sym-octahydroacridine N,P,P‘-Trioxide

Abstract

The ligand 4,5-bis(diphenylphosphino)-sym-octahydroacridine N,P,P′-trioxide (10) was obtained from a multistep synthesis and characterized by spectroscopic methods, and two crystal forms were examined by single-crystal X-ray diffraction techniques. The coordination behavior of the trifunctional ligand toward La(NO 3 ) 3 and Nd-(NO 3 ) 3 was examined, and the molecular structures of the complexes La(10)(NO 3 ) 3 ‚MeOH and Nd(10)(NO 3 ) 3 ‚ MeOH were determined by single-crystal X-ray diffraction methods. The molecules form chains along the z axis in which the ligand bonds in a bidentate mode to one La(NO 3 ) 3 or Nd(NO 3 ) 3 by using the N-O and one of the PdO donor centers. The second PdO donor group in the ligand bridge bonds to a second La(10)(NO 3 ) 3 or Nd-(10)(NO 3 ) 3 unit. The coordination behavior of 10 contrasts with that of the related but structurally more flexible trifunctional ligand 2,6-bis[(diphenylphosphino)methyl]pyridine N,P,P′-trioxide, which acts as a tridentate ligand toward f-element ions.

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

“…The compound displays a low intensity parent ion [M + H + ], intense [M + Na + ] and [2M + Na + ] ions and a strong infrared absorption, Ȟ = 1188 cm -1 , that is assigned to the phosphoryl stretch. The31 P NMR spectrum for 4 shows a single resonance, į = 30.8, whose value is similar to the shifts displayed by examples of compounds from the classes E-I that carry diphenylphosphine oxide substituent groups[11][12][13][14][15][16][17][18][19][20][21][22][23][24]. The 1 H and 13 C NMR spectra are also consistent with the expected structure.…”

“…The 1 H NMR spectrum displays a singlet at į = 5.40 that is comparable to shifts displayed by 1 and 2, į = 5.46 and 5.47, respectively, and these are assigned to the methylene group separating the pyridine and pyrazole rings. The 1 H NMR spectrum also contains a doublet, į = 4.22 (J HP = 13.8 Hz), that is assigned to the methylene group spanning the pyridine ring and the diphenylphosphine oxide substituent, and these data compare favorably with data for examples of compounds of types E-I[11][12][13][14][15][16][17][18][19][20][21][22][23][24]. The 13 C NMR spectrum contains resonances diagnostic of the two inequivalent methylene group environments: į = 31.2 (J CP = 65.9 Hz) and 51.2.…”

“…A view of the molecular structure is shown in Figure 10, and selected bond lengths are listed in Table 4. As found with 2, the initially isolated 1:1 complex transforms upon crystallization to a 2:1 complex with the composition, [Pr (5) [11][12][13][14][15][16][17][18][19][20][21][22][23][24]. The placement of pyridine and 1-methylpyrazole at the weaker end of the series derives from the relatively softer character of N atom donors.…”

“…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.…”

Grignard Reactions in Cyclopentyl Methyl Ether

“…Althoughs everal efficient approaches of tramadol have been published, [17] ag reen method amenablet ot he large-scale synthesis is still anticipated. Thus, aC PME solution of (3-methoxyphenyl)magnesium bromide (2b)w as treated with aminoketone 7 [18] at À78 8Ct or oom temperature to afford amino alcohol (AE)-8,w hichw as, without purification, treated with 4 m hydrochloric acidi nC PME to provide tramadol hydrochloride [(AE)-9]a sacolorless solid after recrystallization from acetone, with an overall yield of 61 %f rom 7 (Scheme 1). Althougha ne xact diastereomeric ratio of (AE)-8 was not determined due to the complexity of the NMR spectrum of the crude product, smooth recrystallization of the desired isomer (AE)-9 indicated that the Grignard addition had occurred in as tereoselective manner.…”