Triphenylphosphane Oxide Research Articles

Syntheses and Spectroscopic Characterization of Selected Methyl Quinolinylphosphonic and Quinolinylphosphinic Acids; Rationalized based on DFT Calculation

Abstract: The quinoline derivatives arouse interest due to their broad spectrum of activity. The phosphorus compounds under investigation, quinolinylphosphonic and -phosphinic acids and aminophenylphosphonic and -phosphinic acids, possess potent bioactive properties, mimicking amino acids, phosphate esters, anhydrides, or carboxylate groups in enzymes. Despite its potential value, there is no reported example of quinolinylphosphonic or - phosphinic acids with phosphonic or phosphinic functional groups connected directly to the benzene ring in quinoline constitution. The selected quinoline derivatives have been synthesized by adopting the Skraup-Doebner-Von Miller reaction. To this end, the syntheses of aminophenylphosphonic and -phosphinic acids were conducted and afforded the target products with high yield. All structures have been proven by the combination of NMR, IR, MS, and HRMS techniques and were rationalized based on DFT calculation. The structures of triphenylphosphane oxide (TPO), diphenylphosphosphinic acid (1c), (tert-butyl)phenylphosphinic acid (1d) and bis(3-nitrophenyl)phosphinic acid (2c) were determined by single-crystal X-ray diffraction measurements. The Hirshfeld surface analyses for 1c, 1d and 2c were performed to analyze the intermolecular interactions in their crystal structures. According to our findings, the presence of numerous intermolecular PO•••H, NO•••H, and CH•••O contacts stabilizes the crystal structures. The NO•••H interactions manifest in the IR spectrum of 2c crystal as a narrow band with a maximum at 3088 cm-1. The PO•••H intermolecular interactions are attributed to a weak experimental band at 1288 cm-1.

Preparation of Eu(Avobenzone)3TPPO by precipitation method and its luminescence performance

Using Eu2O3 as raw material, anhydrous ethanol as solvent system, 1-(4-Methoxyphenyl)-3-(4-tert-butylphenyl)-1,3-propanedione (Avobenzone) as first ligands and triphenylphosphane oxide (TPPO) as second ligands, the rare earth complex Eu(Avobenzone)3TPPO has been successfully prepared by precipitation method. The Eu(Avobenzone)3TPPO were characterized by fluorescence spectrum analysis (FS), Fourier transform infrared spectroscopy(FT-IR) and color coordinate calculation. The thermal stability of Eu(Avobenzone)3TPPO was studied by thermogravimetry differential scanning calorimetry (TG-DSC). The results showed that Eu(Avobenzone)3TPPO emitted strong red characteristic fluorescence, the optimal excitation wavelength was 397nm, the characteristic emission wavelength was 612 nm, and the color coordinates were (0.66, 0.34). Eu(Avobenzone)3TPPO decomposes at about 200°C it shows good thermal stability.

Local Geometry Symmetry and Electrostatic Distribution Dominated Eight‐Coordinate β‐Diketone DyIII SIMs

To further explore the correlation among the relaxation dynamics, geometry symmetry and ligand field of DyIII SIMs, three β‐diketone mononuclear DyIII complexes, formulating as [Dy(thd)2(NO3)(TPPO)2] (1), [Dy(tfa)2(NO3)(TPPO)2] (2) and [Dy(thd)3(4‐Py)2] (3) (thd = 2,2,6,6‐tetramethyl‐3,5‐heptanedione, tfa = trifluoroacetylacetonate, Tppo = Triphenylphosphane oxide and 4‐Py = 4‐methylpyridine) have been synthesized. Single‐crystal X‐ray diffractions reveal that complexes 1–3 are all eight‐coordinated mononuclear structures with D2d, C2v and D4d local symmetry, respectively. Magnetic analysis reveals that all complexes 1–3 exhibit field‐induced single‐ion magnets (SIMs) behavior resulted from the mixed eigenstates of ground state doublets. The differences in the results of energy barrier indicate that the local geometry symmetry and electrostatic distribution of DyIII ions dominate the magnetic property. Furthermore, the relationship between the structure and magnetism of eight‐coordinated DyIII ions SIMs with the SAP N2O6 coordination environment was also discussed via correlation between the anisotropy axis and coordinating geometry symmetry.

A 1:2 co-crystal of 2,2'-thiodi-benzoic acid and tri-phenyl-phosphane oxide: crystal structure, Hirshfeld surface analysis and computational study.

The asymmetric unit of the title co-crystal, 2,2'-thiodi-benzoic acid-tri-phenyl-phosphane oxide (1/2), C14H10O4S·2C18H15OP, comprises two mol-ecules of 2,2'-thiodi-benzoic acid [TDBA; systematic name: 2-[(2-carb-oxy-phen-yl)sulfan-yl]benzoic acid] and four mol-ecules of tri-phenyl-phosphane oxide [TPPO; systematic name: (di-phenyl-phosphor-yl)benzene]. The two TDBA mol-ecules are twisted about their di-sulfide bonds and exhibit dihedral angles of 74.40 (5) and 72.58 (5)° between the planes through the two SC6H4 residues. The carb-oxy-lic acid groups are tilted out of the planes of the rings to which they are attached forming a range of CO2/C6 dihedral angles of 19.87 (6)-60.43 (8)°. Minor conformational changes are exhibited in the TPPO mol-ecules with the range of dihedral angles between phenyl rings being -2.1 (1) to -62.8 (1)°. In the mol-ecular packing, each TDBA acid mol-ecule bridges two TPPO mol-ecules via hy-droxy-O-H⋯O(oxide) hydrogen bonds to form two three-mol-ecule aggregates. These are connected into a three-dimensional architecture by TPPO-C-H⋯O(oxide, carbon-yl) and TDBA-C-H⋯(oxide, carbon-yl) inter-actions. The importance of H⋯H, O⋯H/H⋯O and C⋯H/H⋯C contacts to the calculated Hirshfeld surfaces has been demonstrated. In terms of individual mol-ecules, O⋯H/H⋯O contacts are more important for the TDBA (ca 28%) than for the TPPO mol-ecules (ca 13%), as expected from the chemical composition of these species. Computational chemistry indicates the four independent hy-droxy-O-H⋯O(oxide) hydrogen bonds in the crystal impart about the same energy (ca 52 kJ mol-1), with DTBA-phenyl-C-H⋯O(oxide) inter-actions being next most stabilizing (ca 40 kJ mol-1).

Triphenylphosphane Oxide Complexes of Lanthanide Nitrates: Polymorphs and Photophysics

A series of mer‐[Ln(NO3)3(Ph3PO)3] complexes were prepared from Ln(NO3)3·xH2O and Ph3PO in chloroform (Ln = La, Nd, Sm, Eu, Gd, Tb, Dy, and Er). The La and Nd complexes were 0.25 CHCl3 solvates, whereas the others were solvent‐free. The identical reaction using Yb(NO3)3·xH2O produced the unique salt trans‐[Yb(NO3)2(Ph3PO)4][Yb(NO3)4(Ph3PO)]·Et2O. All nitrate ions in all complexes are η2‐chelating. A comparison of the various [Ln(NO3)3(Ph3PO)3] structures, including those in the literature, reveals at least four common polymorphs, each of which is represented by isomorphic structures of multiple Ln ions. Luminescence of mer‐[Ln(NO3)3(Ph3PO)3] (Ln = Y, La, Nd, Sm, Eu, Gd, Tb, and Dy), trans‐[Yb(NO3)2(Ph3PO)4][Yb(NO3)4(Ph3PO)] and Ph3PO assignments are reported. Latva's empirical rule allows for the antenna effect, in which energy is transferred from the triplet state of the Ph3PO ligand, to occur only for Tb3+. Excitation via Ph3PO results in strong green luminescence for Tb3+ having twice the intensity as that which results from direct excitation of the f‐f transitions.

Palladium iminophosphorane complexes: the pre-cursors to the missing link in triphenylphosphane chalcogenide metallacycles.

Herein we report on the synthesis, characterization and the ensuing chemistry of iminophosphorane palladacycles. Treatment of Ph3P[double bond, length as m-dash]N-(2-OHC6H4), 1, with sodium tetrachloropalladate gives 2 with the ligand as terdentate [C,N,O] allowing for only one μ-Cl ligand bonding the metal centers, resulting in a dinuclear complex. Treatment of 2 with PPh3 gives the mononuclear complex 3, whereas the reaction of 2 with diphosphanes Ph2P(CH2)nPPh2 in 1 : 2 ratio gives mixtures of 4 and 5 (n = 2) and 6 and 7 (n = 3). From them, the mononuclear complexes 4 and 6, and the dinuclear compounds, 5 and 7, were obtained with the parent ligand as bidentate [C,N]. The former two are of zwitterionic nature void of any counterion, with the phosphane ligand in the chelating mode. In a remarkable case of chemical serendipity, a solution of 2 left to stand produced crystals of complex 8: this is the missing link in the series of triphenylphosphane chalcogenide metallacycles. The experiment is repeatable; however, direct metallation of triphenylphosphane oxide was not possible.

Synthesis and characterization of iron(II) and iron(III) complexes with a tridentate O,N,O′-ligand

The coordination chemistry of the ligand precursor 1-benzoyl-4,5-dihydro-3,5-bis(trifluoromethyl)-1H-pyrazol-5-ol (1a) to iron(II) acetate was studied. In dependence of the added co-ligand different complex geometries were observed. In case of 4-dimethylaminopyridine (DMAP) as co-ligand an octahedral iron(II) complex was found with an O,N,O′-coordination of the tridentate ligand (1a-2H), in which the ligand is planar, the oxygen donors are trans to each other, and the nitrogen donor is in a cis position. The other coordination sites on the iron center are occupied by DMAP ligands. In contrast to that, with triphenylphosphane as the co-ligand an oxidation process took place, which revealed an octahedral iron(III) complex with a comparable geometry for the tridentate ligand (O,N,O′-coordination, 1a-2H) demonstrating the usefulness of 1a-2H to stabilize different oxidation states. The additional coordination sites are occupied by one triphenylphosphane oxide and ethoxide ligands. Interestingly, the ethoxide ligands act as bridging ligands to form a bimetallic complex.

Chemistry of Phosphorus Ylides. Part 36 Reactions of 2-Hydroxyisoindole-, Isoindoline-, and Indane-1,3-Dione With Stable and Active Phosphonium Ylides

The stabilized alkylidenephosphoranes namely, acetyl-, benzoyl-, methoxycarbonyl-, and ethoxycarbonyl-methylenetriphenylphosphorane react with 2-hydroxyisoindole-1,3-(2H)dione to give the corresponding isoindoline-ylidenes, along with triphenylphosphane oxide. On the other hand, the reaction of active phosphacumulenes, (N-phenyliminovinylidene)-, and (2-oxovinylidene)-triphenylphosphorane with hydroxyisoindole-, isoindoline-, and indane-1,3-dione afforded phosphanylidenecyclobutylidenes derivatives, together with triphenylphosphane oxide. Mechanisms accounting for the formation of the new products are discussed. The antimicrobial activities for the new compounds are also reported. Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.

Chromium Pentacarbonyl-Substituted Organotin(II) Cation Stabilized byp-Dimethylaminopyridine or Triphenylphosphane Oxide

The syntheses of the heteroleptic organostannylene chromium pentacarbonyl complexes [4-t-Bu-2,6-{P(O)(Oi-Pr)2}2C6H2(X)SnCr(CO)5] (2, X = ClO4; 3, X = OTf) and [4-t-Bu-2,6-{P(O)(Oi-Pr)2}2C6H2(L)SnCr(CO)5][ClO4] (4, L = p-Me2NC5H4N; 5, L = Ph3PO) are reported. In complex 2, as its toluene solvate 2·C7H8, and 3, as its toluene solvate 3·0.5C7H8, the perchlorate and triflate anions coordinate the tin atom at Sn–O distances of 2.170(3) and 2.178(3) Å, respectively. In the complexes 4 and 5, however, the perchlorate anion is displaced from the tin atom by the 4-dimethylaminopyridine and triphenylphosphane oxide donor, respectively, to give salt-like solid-state structures. In addition to the single-crystal X-ray diffraction studies all compounds were characterized by multinuclear NMR and IR spectroscopy, electrospray mass spectrometry, and elemental analysis. DFT calculations with subsequent NBO analyses reveal the bonding of both the 4-dimethylaminopyridine and triphenylphosphane oxide to be donor–acceptor-like with charge transfer from these donor molecules to the tin atoms.

Reduction of Aromatic and Aliphatic Esters Using the Reducing Systems MoO2(acac)2 or V(O)(OiPr)3 in Combination with 1,1,3,3‐Tetramethyldisiloxane

AbstractAn efficient reduction of aromatic and aliphatic esters with 1,1,3,3‐tetramethyldisiloxane in combination with [MoO2(acac)2] or [V(O)(OiPr)3] is reported. In the former system, the presence of triphenylphosphane oxide allows high conversion and good isolated yield to be reached. For the latter system, no ligand is necessary to obtain the corresponding alcohols with similar results.

DMEAD: a new dialkyl azodicarboxylate for the Mitsunobu reaction

Di-2-methoxyethyl azodicarboxylate (DMEAD) is prepared in 65% yield in two steps as a crystalline solid. Use of DMEAD in the Mitsunobu reaction of a variety of alcohols with pronucleophiles results in good yields of the products under sufficient stereospecificity of inversion, as conventional diisopropyl azodicarboxylate (DIAD) does. Isolation of the product is, however, much easier with DMEAD than that with DIAD, because the hydrazine produced from DMEAD is highly hydrophilic and is completely separable by a simple extraction into neutral water. Purification of the organic layer, after separation of the other by-product, triphenylphosphane oxide, by filtration, easily provides high purity of the product in a good yield. Concentration of the water layer yields the hydrazine, which can be reused for the preparation of DMEAD. One-step removal of the two by-products by the aqueous extraction was also possible when trimethylphosphane and DMEAD were employed.

Donor and ate‐Coordination in Rare‐Earth Metal Bis(dimethylsilyl)amide Complexes

AbstractComplete thf donor exchange is observed when complexes Ln[N(SiHMe2)2]3(thf)2 (Ln = La, Nd) are treated with the monofunctional donor molecules triphenylphosphane oxide, N‐methylimidazole, and 1,3‐dimethylimidazolin‐2‐ylidene. The resulting complexes Ln[N(SiHMe2)2]3(donor)2 exhibit a trigonal‐bipyramidal coordination geometry with the donor molecules located in the apical positions. Bifunctional chelating donors 1,10‐phenanthroline, 1,2‐bis(dimethylphosphanyl)ethane, and N,N,N′,N′‐tetramethylethylenediamine give discrete complexes Ln[N(SiHMe2)2]3(phen) (Ln = Sc, La, Nd), Nd[N(SiHMe2)2]3(dmpe), and La[N(SiHMe2)2]3(tmeda). The phen adducts are isostructural as demonstrated for the large Nd3+ and small Sc3+ centers by X‐ray structure analyses and display a distorted square‐pyramidal coordination geometry in the solid state. The distinct coordination of various donor molecules implies subtle changes of the Si–H bonding which can be straightforwardly examined by NMR and FTIR spectroscopy. Ate complex {Y[N(SiHMe2)2]4Li}2 can be isolated and crystallized from Y(OTf)3–Li[N(SiHMe2)2]–hexane reaction mixtures. Dimerization is accomplished by unusual intermolecular Li···H–Si interactions.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

Complexes of Niobium(V) and Tantalum(V) Halides with Ligands that Contain N–C=O and P=O Functionalities: A Synthetic and Structural Study

AbstractThe reactions of niobium and tantalum pentahalides, MX5, with dialkylureas (tetramethyl‐ and tetraethylurea, TMU and TEU, respectively), amides (N,N,dimethylformamide, DMF, N,N‐diethylformamide, DEF, N‐phenylacetamide, PhA), and P=O‐containing compounds (triphenylphosphane oxide, TPPO, and trimethyl phosphate, TMP) are not dependent on the reactant to metal molar ratio, and afford hexacoordinate complexes of the general formula MX5(L). The only exception is given by the reaction of TaBr5 with TMU, which proceeds by bromide migration from one metal center to another, and provides the ionic adduct [TaBr4(TMU)2][TaBr6]. Hydrolysis of TaCl5(TMP), due to adventitious water, has yielded the dinuclear species Ta2(μ‐O)Cl8(TMP)2. All compounds have been fully characterized in solution, and X‐ray crystal structures have been determined for NbCl5(TEU), NbCl5(DMF), TaCl5(DMF), TaCl5(PhA), TaBr5(PhA), TaCl5(TPPO), [TaBr4(TMU)2][TaBr6], and Ta2(μ‐O)Cl8(TMP)2. No evidence for formation of M=O bonds due to oxygen atom transfer from the ligand to the metal has been observed in any case. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

Unprecedented Rearrangement of Molybdenum(VI) Oxide to (μ2‐Oxido)‐bis[dioxidomolybdenum(VI)] Hexamolybdate.

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Unprecedented Rearrangement of Molybdenum(VI) Oxide to (μ2‐Oxido)bis[dioxidomolybdenum(VI)] Hexamolybdate

AbstractMoO2(acac)2 reacts with water, amides, sulfoxides, and phosphane oxides in aqueous methanol, under mild conditions, to afford a new family of molybdates of composition [Mo2O5L6][Mo6O19] (L = H2O, dimethylformamide, dimethylacetamide, dimethyl sulfoxide, dibutyl sulfoxide, tributylphosphane oxide, triphenylphosphane oxide, hexamethylphosphoramide). The crystal and molecular structures of the two first structurally characterized (μ2‐oxido)bis[dioxidomolybdenum(VI)] hexamolybdates were established by X‐ray diffraction analysis. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)

Synthesis, Structures and Properties of Cluster Complexes [H 3 O(Ph 3 PO) 3 ] 2 [Mo 6 Cl 14 ] and [H(Ph 3 PO) 2 ] 2 [Re 6 S 6 Br 8

New cluster compounds [H3O(Ph3PO)3]2[Mo6Cl14] (I) and [H(Ph3PO)2]2[Re6S6Br8] (II) have been prepared by the reaction of a acetonitrile solution of triphenylphosphane oxide Ph3PO with octahedral cluster complexes of molybdenum (H3O)2Mo6Cl14·6H2O and rhenium K2Re6S6Br8, respectively, (with addition of several drops of HBr). The structures and properties of the products were studied by single-crystalX-ray diffraction and NMR and luminescence spectroscopic methods. The compounds studied are characterized by strong hydrogen bonds with O–O distances of 2.45–2.51 Å (I) and 2.34–2.41 Å (II); unusual H-bonded cationic trimers, [H3O(Ph3PO)3]+, were found in compound I. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)

Synthesis, Structures, and Properties of meso‐Phosphorylporphyrins: Self‐Organization through P–Oxo–Zinc Coordination

The synthesis, structures, and optical and electrochemical properties of meso-phosphorylporphyrins are described. The copper-catalyzed carbon-phosphorus cross-coupling reaction of a meso-iodoporphyrin with di-n-butyl phosphite and diphenylphosphane oxide has proved to be an efficient and general method for the synthesis of meso-phosphorylporphyrins. Zinc phosphorylporphyrins thus obtained readily undergo self-organization through P-oxo-Zn coordination to form noncovalently linked, cofacial porphyrin dimers or linear oligomers, which have been characterized by spectroscopic methods and X-ray crystallographic analyses. In toluene, CH(2)Cl(2), and CHCl(3), the zinc phosphorylporphyrins exist mostly as dimers or monomers, depending on their concentrations, the temperature, and the presence of additives. The self-association constants for dimerization in toluene have been determined by UV/Vis absorption titration measurements. The meso-diphenylphosphorylporphyrin dimer displays excitonic coupling of the Soret band with a splitting energy of 940 cm(-1). Fluorescence lifetimes of the zinc phosphorylporphyrins have been found to be affected only slightly by the concentration of the solution, and by the addition of triphenylphosphane oxide, suggesting that the effect of dimerization on their photodynamics in the S(1) state is negligible. On the other hand, the effect of dimerization is clearly reflected in their electrochemical oxidation processes, as the initially produced radical cations are efficiently delocalized over the two porphyrin rings. These findings demonstrate the potential utility of meso-phosphorylporphyrins as new models for the special pair in photosynthesis and as new building blocks for porphyrin-based supramolecular materials.

Synthesis and Luminescent Properties of Novel Europium(III) Heterocyclic β‐Diketone Complexes with Lewis Bases: Structural Analysis Using the Sparkle/AM1 Model

AbstractTris(β‐diketonato)europium(III) complexes of general formula [Eu(TPI)3·L], with chelating ligands such as 3‐phenyl‐4‐(4‐toluoyl)‐5‐isoxazolone (HTPI) and adduct‐forming reagents [L = H2O, tri‐n‐octylphosphane oxide (TOPO), triphenylphosphane oxide (TPhPO), 1,10‐phenanthroline], have been synthesized and characterized by elemental analysis and FT‐IR, 1H NMR, and photoluminescence spectroscopy. The coordination geometries of the complexes were calculated using the Sparkle/AM1 (Sparkle model for the calculation of lanthanide complexes within the Austin model 1) model. The ligand–Eu3+ energy‐transfer rates were calculated using a model of intramolecular energy transfer in lanthanide coordination complexes reported in the literature. The room‐temperature PL spectra of the europium(III) complexes are composed of the typical Eu3+ red emission, assigned to transitions between the first excited state (5D0) and the multiplet (7F0–4). The results clearly show that the substitution of water molecules by TOPO leads to greatly enhanced quantum yields (i.e., 1.3 % vs. 49.5 %) and longer 5D0 lifetimes (220 vs. 980 μs). This can be ascribed to a more efficient ligand‐to‐metal energy transfer and a less efficient nonradiative 5D0 relaxation process. The theoretical quantum yields are in good agreement with the experimental quantum yields, which highlights that the present theoretical approach can be a powerful tool for the a priori design of highly luminescent lanthanide complexes. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)

Asymmetric Cyanohydrin Synthesis Catalyzed by Al(salen)/Triphenylphosphane Oxide.

Various aldehydes undergo asymmetric trimethylsilylcyanation with (CH3)3SiCN (TMSCN) in the presence of a chiral Al(salen) complex and Ph3PO as the catalyst. This is a double activation where Al(salen) plays the role of Lewis acd and POPh3 acts as a Lewis base. Various kind of aldehydes were subjected to the enantioselective addition of (CH3)3SiCN at temperatures between –40 °C and –50 °C. Hydrolysis of the adducts gave cyanohydrins with over 90 % yield and 80 % ee in most cases. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)

Asymmetric Cyanohydrin Synthesis Catalyzed by Al(salen)/Triphenylphosphane Oxide

AbstractVarious aldehydes undergo asymmetric trimethylsilylcyanation with (CH3)3SiCN (TMSCN) in the presence of a chiral Al(salen) complex and Ph3PO as the catalyst. This is a double activation where Al(salen) plays the role of Lewis acd and POPh3 acts as a Lewis base. Various kind of aldehydes were subjected to the enantioselective addition of (CH3)3SiCN at temperatures between –40 °C and –50 °C. Hydrolysis of the adducts gave cyanohydrins with over 90 % yield and 80 % ee in most cases. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)