Sabi Varbanov

Platinum(II), platinum(IV), and palladium(II) complexes of amino substituted phosphine oxides: Synthesis, characterization, and antitumor activity

The complexes [Pt(dapo)2Cl2], [PtNH3(dapo)Cl2], [Pt(py)(dapo)Cl2], [Pt(mbpo)Cl2].H2O, [Pt(mbpo)(OH)2Cl2].H2O, [Pd(dapo)2Cl2], and [Pd(mbpo)Cl2], where dapo is dimethyl aminomethylphosphine oxide and mbpo is methyl bis(aminomethyl)phosphite oxide have been synthesized and characterized by elemental analyses, electric conductivity, infrared, 1H NMR and electronic spectra. The ligands are found to be coordinated only via the amino groups. The complexes are of cis-square planar configuration with the exception of [Pt(mbpo)(OH)2Cl2].H2O which is pseudo-octahedral. An in vivo antitumor screening of the complexes against Leukemia L1210 was performed. A considerable activity (T/C = 233%) was observed for [PtNH3(dapo)Cl2]. The activity of the remaining complexes was below the accepted criterion.

Polyurethane foams based on dimethylaminomethylphosphine oxide adducts with ethylene and propylene oxides

Abstract Dimethylaminomethylphosphine oxide (DMAO) is prepared by the Gabriel method from dimethylchloromethylphosphine oxide. Adding to DMAO, ethylene or propylene oxides affords dimethyl-N,N-bis(2-hydroxyethyl)aminomethylphosphine oxide (DMEO) and dimethyl-N,N-bis(2-hydroxypropyl)aminomethylphosphine oxide (DMPO). It is found that DMEO and DMPO can be employed as reactive flame retardants for reducing the combustibility of rigid polyurethane foams without impairing their physical and mechanical properties.

Physicochemical Properties and Theoretical Modeling of Actinide Complexes with a para-tert-Butylcalix [6]arene Bearing Phosphinoyl Pendants. Extraction Capability of the Calixarene toward f Elements

The coordination ability of the hexaphosphinoylated p-tert-butylcalix[6]arene B6bL6 toward actinides is established, as well as its good separation ability of the actinide ions UO2 2+ and Th(IV) over trivalent rare earths such as La(III), Eu(III), and Y(III). Spectrophotometric titration of uranyl with B6bL6 in CH 3CN yields log beta 11 = 7.1 and log beta 12 = 12.5 for the 1:1 and 1:2 (UO2 2+/B 6bL6) species, respectively. Actinide complexes with 1:1 and 1:2 (M/L) stoichiometries are isolated and characterized by elemental analysis, IR, and UV-vis. Compounds 1 and 3 fulfill their CN = 8 just with B 6bL (6), while compounds 2 and 4 require coordinated nitrates and/or water molecules. The luminescence spectra of the uranyl complexes and the parameters such as FWMH, vibronic spacing (upsilon sp), and the U-O bond length, as well as the luminescence lifetimes, permit the understanding of the coordination chemistry of these actinide calixarene complexes. Energy transfer from the B6bL6 ligand to the uranyl ion is demonstrated to be relevant in compound 1 with Q abs = 2.0%. The uranyl complex emission reveals a biexponential decay with tau s from 210 to 220 micros and tau L from 490 to 650 micros for compounds 1 and 3, respectively. The liquid-liquid extraction results demonstrate the good extraction capability of B 6bL (6) toward actinides but not for rare earths at room temperature. The extracted species keeps the 1(cation)/1(calixarene) ratio for the UO2 2+, Th 4+, and Eu 3+ ions. A good capacity of B6bL 6 toward Th4+ ions using aqueous phase 2 containing even up to 0.3 M thorium nitrate and an organic phase of 2.47 x 10 (-4) M B6bL6 in chloroform is found. The spectroscopic properties of the isolated uranyl complexes and the extraction studies reveal a uranophilic nature of B6bL6. The molecular modeling results are in good agreement with the experimental findings.

Are fancy acidic or neutral ligands really needed for synergism in ionic liquids? A comparative study of lanthanoid extraction in CHCl3 and an ionic liquid

The study of trivalent lanthanoid (La, Nd, Eu, Ho and Lu) extraction by two individual ligands, one acidic such as a pyrazolone derivative, 3-methyl-1-phenyl-4-(4-phenylbenzoyl)-pyrazol-5-one (HL), and one neutral such as 5,11,17,23-tetra-tert-butyl-25,26,27,28-tetrakis-(dimethylphosphinoylmethoxy)calix[4]arene (SIV), was performed in CHCl3 and in one ionic liquid, IL 1-methyl-1,3-butylimidazolium-bis(trifluoromethanesulfonyl)imide ([C1C4im][Tf2N]), in order to establish and examine the impact of the diluent on individual and synergistic extraction processes. Chloride aqueous medium and constant ionic strength μ = 0.1 M were set in both cases. The parameters of the extraction processes were determined. Comparison between the two diluents was made on the basis of (i) composition of the extracted species: LnL3·HL in CHCl3vs. LnL3 in IL with HL as a single extractant (L− represents the HL anion), and LnL3·SIV in the presence of the phosphorus-containing calix[4]arene in both diluents; and (ii) values of the equilibrium constants and the synergistic enhancements; the separation factors between metals were evaluated as well. The IL medium appears far superior to the molecular solvent in terms of individual and overall synergistic extraction efficiencies. However, the huge differences in extraction efficiencies observed in CHCl3 for chemically different ligands are erased in the IL medium, thus modifying the lever arms on which chemists should rely in order to obtain even better extracting systems in ionic liquid media.

IR and Raman study of Pt(II) and Pd(II) complexes of amino substituted phosphine oxides: Normal coordinate analysis

Abstract IR and Raman spectra of Pt(dapo) 2 Cl 2 and Pd(dapo) 2 Cl 2 (dapo=dimethyl(aminomethyl)phosphine oxide) have been measured in the 200–4000 cm −1 frequency range. Both the IR and Raman spectra show that dimethyl(aminomethyl)phosphine oxide ligands are monodentate coordinate. The results from the normal coordinate analysis calculations confirm the monodentate coordination of the ligands in agreement with some literature data. For Pd(dapo) 2 Cl 2 complex the possibility for bidentate coordination of one dapo ligand is also considered.

Synthesis and Plant Growth Regulating Activity of New Triazolo- and Pyrazolopyrimidine Derivatives Of Aminomethyl, Aminoalkyloxymethyl Dimethylphosphine Oxides and (Aminomethane)Phosphonic Acid Esters

Abstract New triazolo[4,5-d]pyrimidine and pyrazolo[3,4-d]pyrimidine derivatives of aminomethyl-and aminomethyloxymethyl dimethylphosphine oxides 8–14 as well as of esters of (aminomethane) phosphonic acid 18–20 were synthesized. The structure of the compounds prepared was confirmed by means of elemend analysis, IR, 1H- and 31P(1H)-NMR spectroscopy. Tertiary phosphine oxides 8, 9 and 12 as well as phosphonate 20 showed herbicidal and plant growth regulating activity.

SYNTHESIS OF METHYL-BIS(AMINOMETHYL)PHOSPHINE OXIDE AND ITS PHTHALIMIDO DERIVATIVES

Abstract The synthesis of methyl-bis(aminomethyl)phosphine oxide (Ia) is described starting from methyl-bis(chloromethyl)phosphine oxide (MBCPO) and using as an intermediate methyl-bis(phthalimidomethyl)phosphine oxide (II). The following substituted phthalimido derivatives have also been prepared: methyl-bis(4-nitrophthalimidomethyl)phosphine oxide (III), methyl-bis(4-aminophthalimidomethyl)phosphine oxide (IV), methyl-bis(4-benzamidophthalimidomethyl)phosphine oxide (V), methyl-bis(4-carboxy-phthalimidomethyl)phosphine oxide (VI) and its dicyclohexylammonium salt (VII). Methyl-bis(aminomethyl)phosphine oxide (Ia) is isolated and characterized as a dihydrochloride (I).

Addition products of dialkyl phosphites with a Schiff base as components increasing the combustion resistance of polymers

Abstract New phosphorus- and nitrogen-containing compounds: viz. 4,4′-bis[N-methyl(dimethoxyphosphonyl)-1-phenyl]diaminodiphenylmethane, 4,4′-bis[N-methyl(diethoxyphosphonyl)-1-phenyl]diaminodiphenylmethane and 4,4′-bis[N-methyl(diisopropoxyphosphonyl)-1-phenyl]diaminodiphenylmethane, have been synthesized via the addition of dialkyl phosphites to a Schiff base 4,4′-bis(benzylideneamino)diphenylmethane. It has been shown these addition products can be used as non-reactive additives increasing the combustion resistance of epoxide resin and difurfurylidene acetone polymer.

Vibrational study of new Pt(II) and Pd(II) complexes with functionalized nitrogen-containing tertiary phosphine oxides. Ab initio study of ortho-, meta- and para-dimethylphosphinylmethyleneoxyaniline

Vibrational study of new Pt(II) and Pd(II) complexes of functionalized nitrogen-containing tertiary phosphine oxides, namely ortho-, meta- and para-dimethylphosphinylmethyleneoxyaniline (o-, m- and p-dpmoa), (CH3)2P(O)CH2OC6H4NH2, have been presented. Geometry optimization of the ligands was performed at HF/6-31G* and B3LYP/6-31G* levels of the theory. Harmonic frequencies were calculated at HF/6-31G* optimized geometries. Relative gas-phase and solution-phase (H2O and CH3CN) basicities of o-, m- and p-dpmoa ligands have been determined by ab initio calculations at STO-3G level with the Onsager reaction field model. On the basis of the vibrational study, physical and analytical data it was suggested that the ligands in the complexes studied coordinate through the amino group and form square-planar platinum and palladium complexes of the general formula ML2Cl2 (M = Pt, Pd, L = o-, m- and p-dpmoa).

Urea and Thiourea Derivatives of Bis(dimethyl-phosphinoylmethyl)-amine

A group of hitherto unknown 1-aryl-3,3-bis(dimethyl-phosphinoylmethyl)-, 1-benzyl-3,3-bis(dimethyl-phosphinoylmethyl)- and 1-cyclohexyl-3,3-bis(dimethyl-phosphinoylmethyl) ureas and thioureas 1-10 have been synthesized, characterized, and are reported in this article. The compounds were prepared via reaction of corresponding isocyanates or isothiocyanates with the secondary phosporus-containing amine: bis(dimethyl-phosphinoylmethyl)-amine. The composition of the novel compounds was proved by elemental analysis, corresponding structures were confirmed by IR, 1 H-, 31 P-, 31 P{ 1 H}-NMR spectroscopy and by mass spectrometry.