The structures of bis(3-aminophenyl)phosphinic acid and its derivatives in the solid state

Russian Chemical Bulletin - According to IR spectroscopy data, solid bis(3-aminophenyl)phosphinic acid has a zwitterionic structure.     

Synthesis and spectral studies of new N2S2 and N2O2 Mannich base ligands and their metal complexes

New Mannich bases bis(thiosemicarbazide methyl) phosphinic acid H₃L¹ and bis(1-phenylsemicarbazide methyl) phosphinic acid H₃L² were synthesized from condensation of phosphinic acid and formaldehyde with thiosemicarbazide and 1-phenylsemicarbazide, respectively. Monomeric complexes of these ligands, of general formula K₂[Cr^III(L ⁿ )Cl₂], K₃[Fe^II(L¹)Cl₂], K₃[Mn^II(L²)Cl₂], and K[M(L ⁿ )] (M = Co(II), Ni(II), Cu(II), Zn(II) or Cd(II); n = 1, 2) are reported. The mode of bonding and overall geometry of the complexes were determined through IR, UV-Vis, NMR, and mass spectral studies, magnetic moment measurements, elemental analysis, metal content, and conductance. These studies revealed octahedral geometries for the Cr(III), Mn(II), and Fe(II) complexes, square planar for Co(II), Ni(II), and Cu(II) complexes and tetrahedral for the Zn(II) and Cd(II) complexes. Complex formation via molar ratio in DMF solution has been investigated and results were consistent to those found in the solid complexes with a ratio of (M : L) as (1 : 1).     

Synthesis and characterization of new platinum(II) phosphinate complexes

The syntheses of platinum(II) complexes of bis(dimethylphosphinylmethylene)amine and bis(aminomethyl)phosphinic acid were investigated. In the case of bis(dimethyl-phosphinylmethylene)amine the reaction with K₂[PtCl₄] yields the potassium amino-trichloroplatinate K[PtCl₃L] (L?=?bis(dimethylphosphinylmethylene)amine), which was characterized by multinuclear (¹H, ¹³C, ³¹P, and ¹⁹⁵Pt) NMR spectroscopy in solution. Bis(aminomethyl)phosphinic acid reacts with K₂[PtCl₄] under strictly controlled pH conditions to give colorless crystals of the cisplatin analog K[PtCl₂L′] (L′?=?bis(aminomethyl)phosphinate). This complex was characterized by multinuclear NMR spectroscopy in solution as well as by single-crystal X-ray diffraction in the solid state. The bis(aminomethyl)phosphinate coordinates to platinum via both amino functions, thus acting as a chelating ligand.     

Experimental and Quantum Chemical Studies of 2-Phosphinylphenol Derivatives

Carbon-oxygen bonds ortho to a phosphoryl group in triarylphosphine oxides undergo cleavage when the oxides are either fused with potassium hydroxide or treated with potassium tert-butoxide in refluxing toluene, presumably through a nucleophilic addition-elimination mechanism. Thus, bis(2-hydroxyphenyl)phenylphosphine oxide is produced along with the expected 2-phenoxyphenyl(phenyl)phosphinic acid from 10-phenyl-10H-phenoxaphosphine 10-oxide. The latter starting material is also produced, together with bis(2-hydroxyphenyl)phenylphosphine oxide, when bis(2-methoxyphenyl)phenylphosphine oxide is fused with potassium hydroxide. Fusion of bis(2-methoxyphenyl)phenylphosphine oxide with sodium hydroxide, however, yields 2-hydroxyphenyl(phenyl)phosphinic acid. Ab initio quantum chemical studies confirm that the downfield ³¹P chemical shift that is observed in 2-phosphinylphenols is due to hydrogen bonding to the phosphoryl group.     

Pyrene‐Based Fluorescent Supramolecular Hydrogel: Scaffold for Energy Transfer

The self‐assembled gelation of an amino‐acid‐based low molecular weight gelator having a pyrene moiety at the N terminus and a bis‐ethyleneoxy unit linked with succinic acid at the C terminus is reported. This amphiphile is capable of gelating binary mixtures (1/3 v/v) of CH₃CN/water, DMSO/water, and DMF/water, and the minimum gelation concentration (MGC) varied from 0.2 to 0.3 % w/v. The sodium salt of the amphiphile efficiently gelates water with an MGC of 1.5 % w/v. The participation of different noncovalent interactions in supramolecular gelation by formation of fibrillar networks was investigated by spectroscopic and microscopic methods. High mechanical strength of the supramolecular gels is indicated by storage moduli on the order of 10³ Pa. The hydrogel was utilized for energy transfer, whereby inclusion of only 0.00075 % w/v of acridine orange resulted in about 50 % quenching of the fluorescence intensity of the gel through fluorescence resonance energy transfer.     

Synthesis and characterization of silicon-containing phenylated soluble aramids

New high molecular weight (inherent viscosities, 1.21–0.50 dL/g) aramids having silicon and pendant phenyl groups were synthesized by low temperature interfacial polycondensation technique involving the reaction of acid chlorides: bis(4-chlorocarbonylphenyl)dimethylsilane and bis(3-chlorocarbonylphenyl)dimethylsilane with diamines: 2,5-bis(4-aminophenyl)-3,4-diphenyl-thiophene and bis(4-aminophenyl)ether. Copolyamides were obtained by using different proportions of these diamines. All the polymers were completely soluble in organic solvents such as N,N-dimethylacetamide, N-methyl-2-pyrrolidone, and N,N-dimethylformamide. Thermal properties were evaluated by thermogravimetry which showed no weight loss below 325°C in both air and nitrogen atmospheres.     

Synthesis and Characterization of Novel Organosoluble Methyl Substituted Poly(aryl Ether Ketone)s Containing Sulfone Linkage

Several new methyl substituted poly(aryl ether ketone)s containing sulfone linkage with inherent viscosities of 0.62–0.84 dL/g have been prepared from 4,4′‐bis(2‐methylphenoxy)diphenylsulfone and 4,4′‐bis(3‐methylphenoxy)diphenylsulfone with terephthaloyl chloride and isophthaloyl chloride by electrophilic Friedel‐Crafts acylation in the presence of DMF with anhydrous AlCl₃ as a catalyst in 1,2‐dichloroethane, respectively. These polymers having weight‐average molecular weight in the range of 71,000–49,000 are all amorphous and show high glass transition temperatures ranging from 167 °C to 191 °C, excellent thermal stability at temperatures over 400 °C in air or nitrogen, high char yields of 51–58% in nitrogen and good solubility in CHCl₃ and polar solvents such as DMF, DMSO and NMP at room temperature.     

Synthesis,photophysics, and photochemistry of peripherally Schiff base-zinc complex substituted zinc phthalocyanine

The content of this work is based on the introduction of the salicylhydrazone-zinc complexes into the phthalocyanine core. The reaction of the salicylhydrazone substituted ZnPc (1) with the related zinc(II) salt in basic conditions in DMF yielded bis[bis(salicyhydrazone)phenoxy)zinc(II)] phthalocyaninato zinc(II) (5) in which two salicylhydrazone-Zn complexes are linked through oxygen bridges to the macrocyclic core as three-nuclear complex. The novel compound synthesized in this study was fully characterized by general spectroscopic techniques such as FT-IR, UV-vis, ¹H NMR, ¹³C NMR, elemental analysis and mass spectroscopy. In addition, spectral, photophysical (fluorescence quantum yields), and photochemical (generation of singlet oxygen and photo stability under light irradiation) properties of newly synthesized phthalocyanine (5) and the starting Pcs molecules used to obtain this molecule were investigated in DMSO solutions, comparatively.     

Synthesis and photochemical properties of novel pentamethylated norbornadiene containing polyimides

A novel pentamethylated norbornadiene (NBD) based dianhydride, α,α′‐bis‐(3,4,5,6,7‐pentamethylcyclopenta‐2,4‐dienyl)meta‐xylene‐1,2‐dianhydride (3), was prepared from α,α′‐bis‐(pentamethylcyclopentadienyl)meta‐xylene (1) and acetylene dicarboxylic acid. The bis‐adduct formed via Diels–Alder reaction afforded tetra‐acid (2), which was chemically cyclodehydrated to lead the targeted dianhydride (3). New polyimides containing NBD moieties in the main chain were prepared from the dianhydride monomer (3) and various aromatic diamines. The chemical structure of the polymers was confirmed by both ¹H and ¹³C NMR analysis. Their Molecular weights were also measured by SEC. All of these polyimides are soluble at room temperature in common organic solvents, such as chloroform, dichloromethane, THF, DMSO, DMF, and NMP, and show good thermal stabilities. The photochemical isomerization of the NBD into quadricyclane (QC) was investigated by UV/vis spectrophotometry from polymer films using visible sunlight as irradiation source. It was found that the kinetic rate of the conversion NBD‐QC which proceeded smoothly is a first kinetic order. The stored energies released by the transformation of QC groups into NBD ones of the irradiated polymer films were also evaluated by DSC measurement and were found to be around 90 kJ mol^?1. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Preparation of Cyanex 272-containing silica composite by sol–gel method for neodymium adsorption

A kind of silica composite containing bis(2,4,4-trimethylpentyl)phosphinic acid (Cyanex 272) was prepared via a in situ sol–gel approach. ³¹P solid-state NMR and FT–IR spectra were employed to analyze the structure of the composite. The thermal stability and surface properties were characterized, and the adsorption ability towards trivalent neodymium (Nd(III)) was evaluated by batch experiments. The Cyanex 272 loaded silica composite showed the advantage of an effective adsorption of Nd(III) from low acidic or neutral solutions with a capacity of ~50 mg/g. The influence of contact time, acidity and initial metal concentration of the stock solutions on the adsorption were comprehensively investigated.     

Reactions of Bis(chloromethyl)phosphinic(-Phosphinothioic) Chlorides with Silylated Carbamates and Trimethylsilyl N-Trimethylsilylacetimidoate

Bis(chloromethyl)phosphinic chloride reacts with trimethylsilyl methylcarbamate in benzene in the presence of a base to give trimethylsilyl bis(chloromethyl)phosphinate. The same reaction performed without a solvent and in the absence of a base yields trimethylsilyl bis(chloromethyl)phosphinate and bis(chloromethyl)phosphinic anhydride. Reaction of bis(chloromethyl)phosphinic chloride with trimethylsilyl diethylcarbamate yields N,N-diethylbis(chloromethyl)phosphinic amide. The reaction of bis(chloromethyl)phosphinic (-phosphinothioic) chlorides with trimethylsilyl N-trimethylsilylacetimidoate was studied.     

A study of lanthanide p-toluene sulphonic acid complexes in solution

Lanthanide p-toluene sulphonic acid (ptsa) complexes were prepared for La, Pr, Nd, Sm, Eu, Dy, Ho, Er and Yb, and found to exist as Ln(ptsa)₃. Conductivity studies of La(ptsa)₃ in DMSO and DMF suggest 1:2 and, possibly, 1:1 electrolyte behaviour in these solvents, respectively. NMR lanthanide-induced chemical shifts (LIS) for aromatic protons in (ptsa)^? and methyl protons in DMSO, were measured for all complexes as a function of the [Ln³⁺[DMSO] in a medium consisting of CCl₄, DMSO, and CH₃CN. Analysis of the LIS data suggests a change in (ptsa)^? coordination round Ln₃₊ across the lanthanide series.     

Labeling of a bifunctional monophosphinic acid DOTA analogue with <Superscript>111</Superscript>In: Radiochemical aspects and preclinical results

The complex formation of the bifunctional monophosphinic acid DOTA analogue DO3AP^ABn (1,4,7,10-tetraazacyclododecane-4,7,10-triacetic-1-{methyl[(4-aminophenyl)methyl] phosphinic acid}) with ¹¹¹In at a tracer level was analyzed. Formation of a complex between ¹¹¹In and DO3AP^ABn was very rapid even at room temperature and high radiolabeling yields were achieved. As introducing the methylphosphinic acid arm to the DOTA structure generated a chiral centre, more than one peak (probably corresponding to various diastereoisomers) of ¹¹¹In-DO3AP^ABn were separated on HPLC. Four peaks were separated by HPLC, they probably correspond to four diastereoisomers of ¹¹¹In-DO3AP^ABn originating from combination of chirality of complexes of DOTA-like ligands with chirality of coordinated phosphorus atom. Studies in rats showed rapid elimination of radioactivity from the blood and other organs and tissues. The results indicate that DO3AP^ABn represents a promising ligand for radiolabeling of target-specific biomolecules with radiometals.     

Synthesis and characterization of ionic conducting sulfonated polybenzimidazoles

By copolymerization of the disodium‐2,2′‐disulfonate‐4,4′‐oxydibenzoic acid (SODBA), the 4,4′‐oxybis(benzoic acid) (OBBA) with the bis 3,4‐(diaminophenyl)sulfone (BDAPS), a series of high molecular weight sulfonated polybenzimidazoles (sPBI) were prepared by varying the ratio of monomers SODBA/OBBA. Polymers with ion exchange capacity (IEC) ranging from 0 to 3.2 meqH⁺/g were obtained. The chemical structure of the sPBI was confirmed by NMR, Fourier‐transform infra‐red (FTIR). Although the sPBI display a very poor solubility in organic solvents, they are, in the ammonium salt form, soluble in polar aprotic solvents such as DMF, NMP, or DMSO. Tough and ductile membranes from solution casting method were prepared. The water uptake and the ionic conductivity were determined at 30 and 90 °C. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1732–1742, 2010     

柔性配体构筑的三个构象多样的镧系羧酸配位聚合物:合成,结构和荧光性质

利用2,2''-(1,4-亚苯基)二(亚苯基)二(硫基)苯二羧酸(H₂L¹)和2,2''-(2,3,5,6-四甲基-1,4-亚苯基)二(亚甲基)二(硫基)苯二甲酸(H₂L²)2个柔性二羧酸分别与镧系金属盐反应,通过溶剂热方法合成了3个配位聚合物:{[(NH₂(CH₃)₂][Nd(L¹)₂(DMF)]·2DMF}_n(1)和{[Ln(L²)_1.5(H₂O)(DMF)₂]·2DMF}_n[Ln=Ce(2),Pr(3)]。利用元素分析、红外、粉末X射线衍射、热重分析等对配合物进行了表征。X射线单晶衍射分析表明:3个配合物均为二维的层状结构,并且2个配体在配合物中表现出不同的构象。(L¹)^2-在配合物1中表现出顺式和反式2种构象,(L2²)^2-在配合物2和3中仅表现出反式构象。此外,对配合物的热稳定性和荧光性质也进行了研究。     

蝶形主体分子的设计、合成及其包结性能的研究

设计、合成了两种蝶形主体分子：2，5－二（三苯甲基）对苯二酚1，2，5－二（二苯甲基）对苯二酚2.1和2可与许多有机小分子形成配位包合物。用IR表征了主体分子1和2 的包结物， 用¹H NMR测定了主客体分子的摩尔比：1•DMF (1：2)，1•DMSO (1:2)，1 •吡啶 （1：2），1•环戊酮 （2：3）和2•DMF 1：2），2•DMSO （1：2），2 •THF （1：1），2•苯甲醛（1：2），2•苯乙酮 （1：2），2•2，5－己二酮 （1：1），2 •N－甲基－2－吡咯烷酮 （1：3）。单晶X-射线衍射分析了包结物2·苯甲醛的晶体结构，在分子间氢键的相互作用下晶体得以稳定。     

Attachment of anthraquinone derivatives to glassy carbon and the electrocatalytic behavior of the modified electrodes toward oxygen reduction

The electrochemical reduction of oxygen on glassy carbon (GC) electrodes modified with anthraquinones was studied using cyclic voltammetry (CV) and the rotating disk electrode (RDE) technique. Two methods were used in surface modification. The first method comprised immersion of the polished or anodically pretreated GC electrode in a solution containing 9,10-anthraquinone-2-carboxylic acid (AQ-2-COOH) or its anion (AQ-2-COO⁻) in dimethylsulfoxide (DMSO) or 9,10-anthraquinone-2-ethanoic acid (AQ-2-CH₂COOH) or its anion (AQ-2-CH₂COO⁻) in N,N-dimethylformamide (DMF). Alternatively, the surface of the GC disk was modified by anodic oxidation of AQ-2-COOH or AQ-2-COO⁻ in DMSO or AQ-2-CH₂COOH in DMSO or DMF or AQ-2-CH₂COO⁻ in DMF. The modified electrodes showed electrocatalytic activity toward oxygen reduction in 0.1 M acetate buffer pH (4.8), 0.1 M phosphate buffer (pH 8) and 0.1 M NaOH. Atomic force microscopy (AFM) examination of the modified electrodes was carried out and the differences in surface morphology of various modifications were in evidence.     

Synthesis and characterization of silver polymer nanocomposites of 1-vinyl-1,2,4-triazole with acrylonitrile

Novel organic-inorganic nanocomposites were synthesized by chemical reduction of silver ions from silver acetate in DMSO and DMF solutions in the presence of the stabilizing copolymer of 1-vinyl-1,2,4-triazole-acrylonitrile. The solvents DMSO and DMF can act as efficient reducing agents for silver ions, which makes it possible to carry out the reaction under mild conditions and simplify procedures of nanocomposite isolation. The structure and properties of the starting copolymer and related nanocomposites were characterized by UV, IR, and ¹H and ¹³C NMR spectroscopy, as well as transmission electron microscopy and thermogravimetry. The prepared polymer nanocomposites contain 6.8–7.2% silver in the form of nanoparticles with a size of 2–20 nm uniformly dispersed in the polymer matrix. The nanocomposites are readily soluble in DMSO and DMF and do not decompose on heating to 260 °C.