Chiral recognition and supramolecular photoreaction of 1,1′-binaphthol with bovine and human serum albumins

In their pioneering study in 1991, Levi-Minzi and Zandomeneghi discovered that photoirradiation of racemic 1,1′-binaphthol (rac-1) in the presence of bovine serum albumin (BSA) in distilled water gave (R)-1 in 99 % enantiomeric excess (ee) after 77 % of the starting material had been consumed. No similar attempt was made with human serum albumin (HSA). In this study of the effects of phosphate buffer solution on the ground-state affinity and excited-state photobehavior of 1 with serum albumin we found that both BSA and HSA preferentially bind the (S) enantiomer of 1 and that photoreaction of rac-1 mediated by BSA and HSA affords (R)-1 in 98 % ee with 99 % conversion and in 46 % ee with 65 % conversion, respectively.     

Synthesis,characterization and properties of 3,3′-diethyl-1,1′-oxydiethylenedicarbonyl bis(thiourea)

In this paper, 3,3′-diethyl-1,1′-oxydiethylenedicarbonyl bis(thiourea) (DEOECTU), was synthesized by phase transfer catalysis and then characterized by UV, elemental analysis, infrared spectra, mass spectrum, ¹H NMR and TGA. DEOECTU properties, such as response to metal ions, adsorption on sulfide mineral surfaces, and hydrometallurgical performance as flotation collectors, were also investigated. The results indicated that DEOECTU reacted chemically with Cu²⁺ ions through its S and N atoms in the C(=S)–NH–C(=O) group to form a new chelate compound, but no reaction of DEOECTU with Zn²⁺, Pb²⁺, Fe³⁺ or Fe²⁺ ions was observed. The results of adsorption and flotation experiments demonstrated, that compared to pyrite, sphalerite and galena, DEOECTU exhibited a superior collecting power for chalcopyrite and might attach on chalcopyrite surface by chemisorption. The further theoretical analysis from Pearson’s HSAB view point briefly explained the experimental results of the selective response of DEOECTU to Cu²⁺ ions and chalcopyrite.     

Hydrothermal synthesis and characterization of a zigzag neodymium-2,2′-bipyridine-3,3′-dicarboxylate-isonicotinate coordination polymer

A new neodymium(III) coordination polymer, {[Nd(bpdc)(iso)(H₂O)₂] ? (H₂O)_2.25} _n (1), was synthesized by treating neodymium oxide with 2,2′-bipyridine-3,3′-dicarboxylic acid (H₂bpdc), and isonicotinic acid (Hiso) under hydrothermal conditions. Single-crystal X-ray diffraction shows that 1 is a 1-D zigzag chain and extends to 2-D network structure through π–π interactions and hydrogen bonds. Thermogravimetric analysis of 1 displays a considerable thermal stability. The variable-temperature magnetic susceptibility of 1 was measured.     

New saccharinate complexes with 3,3′-azobispyridine ligand: synthesis,characterization, and spectroscopic properties

The new metal complexes with saccharinate (sac) and 3,3′-azobispyridine (3,3′-abpy), [Ni(H₂O)₄(3,3′-abpy)₂](sac)₂ (1), [Cu(sac)₂(H₂O)(μ-3,3′-abpy)]_n (2), [Zn(H₂O)₄(3,3′-abpy)₂](sac)₂ (3), [Cd(sac)₂(H₂O)₂(μ-3,3′-abpy)]_n (4), and [Hg₂(μ-sac)₂(sac)₂(μ-3,3′-abpy)(3,3′-abpy)₂]_n (5), were synthesized and characterized by IR spectra, elemental analysis, and single-crystal X-ray diffraction. Spectroscopic (UV–vis and photoluminescence) and thermal properties were also investigated. Single-crystal X-ray analysis reveals that Ni(II) and Zn(II) are coordinated by four aqua ligands and two nitrogens of 3,3′-abpy, while sac is a counter-ion in 1 and 3. In 2, Cu(II) and all ligands are linked by coordination bonds and 3,3′-abpy ligands connect the Cu(II) centers forming a 1-D coordination polymer. In 4, sac N-coordinated to Cd(II) and distorted octahedral geometry of Cd(II) ion is completed by two aqua and bridging 3,3′-abpy ligands. In 5, sac bridges two Hg(II) ions to generate dinuclear [Hg₂(μ-sac)₂] units. These dinuclear units are connected by 3,3′-abpy to form a 1-D coordination polymer. The photoluminescence spectra of 3 and 5 show blue fluorescent emission bands, and these emissions can probably be assigned to intraligand fluorescent emissions. Thermal decompositions of the compounds are also discussed. For all complexes, magnetic susceptibility measurements show expected magnetic behavior.     

Effect of thermal curing on the properties of thin films based on benzophenonetetracarboxylic dianhydride and 4,4′-diamino-3,3′-dimethyldiphenylmethane

The processing of polyimide films from polyamidic acid solutions involves the simultaeous loss of solvent and chemical conversion, and may imply structural reorganization such as orientation or crystallization. The effect of thermal treatment on the thermal, mechanical and dielectric properties of polymer films based on benzophenonetetracarboxylic dianhydride and 4,4’-diamino-3,3’-dimethyl diphenylmethane have been investigated. The thermal treatment of polyamidic acid at different temperatures led to compounds with different degree of imidization; it turned out that the imidization process took place with high speed until 240 °C and then remained constant. The dynamic mechanical analysis (DMA), contact angles, and dielectric measurements revealed that the storage modulus and contact angles increased with increasing of curing temperature while the dielectric constant decreased.     

Phosphomacrocyclic systems based on 2,2′-dihydroxy-1,1′-dinaphtylmethane

For the first time phosphomacrocyclic systems were synthesized based on 2,2′-dihydroxy-1,1′-dinaphthylmethane, other aromatic diols, and phosphorous hexaethyltriamide. Spontaneous transformation of the obtained macrocycles into the more stable 1,3,2-dioxaphosphacyn and cyclobisamidophosphite was established.     

Crystal structure of 1,1′-biphenyl-2,2′,3,3′-tetracarboxylic and 1,1′-biphenyl-2,2′,3,3′,5,5′,6,6′-octacarboxylic acids: solid-state chiralization and dissociation

X-ray diffraction analysis revealed unexpected stereochemical features accompanying crystal self-assembly of the two title oligocarboxylic acids.     

Electro organic synthesis and characterization of phenol–aniline based copolymers

A new series of copolymers of phenol and aniline poly(PHE-co-ANI) was synthesized at platinum electrode through electro-oxidative polymerization in acetonitrile in the presence of lithium perchlorate as supporting electrolyte. Electro-polymerization was studied by cyclic voltammetry. The resultant copolymers were characterized by UV–Vis, IR, ¹³C and ¹H NMR spectroscopy; surface morphology of the copolymers was investigated by scanning electron microscopy.     

Synthesis,characterization and magnetic properties of coordination polymers of manganese with 1,1′-biphenyl-2,2′-dicarboxylic acid ligands

Three new coordination polymers have been synthesized from 1,1′-biphenyl-2,2′-dicarboxylic acid (2,2-dpa), nitrogen-containing coligands and Mn salts under hydrothermal conditions. The X-ray crystal structures of all three complexes are presented. With the change of nitrogen-containing ligand, the structural features of the complexes also change. The complex prepared without a nitrogen coligand exhibits a one-dimensional covalent chain-like structure, composed of the rare pentanuclear Mn building unit. The complex with 4,4′-bipyridine as a secondary ligand shows a two-dimensional layer structure. With the chelating ligand 1,10-phenanthroline, a discrete molecular complex is synthesized. The magnetic properties of the complex with 4,4′-bipyridine in the temperature range 1.99–300 K are reported.     

Synthesis of chiral 3,3′-disubstituted 1,1′-binaphthyl-2,2′-disulfonic acids

A convenient synthesis of chiral 3,3′-disubstituted 1,1′-binaphthyl-2,2′-disulfonic acids (BINSA, 1) was developed. The key was directed ortho-lithiation of BINSA methyl ester 2 with n-BuLi and subsequent reaction with an electrophile. Electrophiles such as Br₂, I₂, Me₃SiOTf, and i-PrOB(Pin) reacted smoothly with 3,3′-dilithiated BINSA methyl ester, and the corresponding 3,3′-dihalo-, 3,3′-bis(trimethylsilyl)-, and 3,3′-diboryl-BINSA derivatives were obtained in yields of 21–78%. This simple synthetic method is highly attractive since the ability to prepare 3,3′-disubstituted BINOLs in advance can be useful.     

Simple and efficient synthesis of closo-rhoda- and closo-iridacarboranes with π-ligands based on cyclic dienes

Russian Chemical Bulletin -     

Resolution and determination of the absolute configuration of 3,3′4,4′-tetramethyl-1,1′-diphosphaferrocene-2-carboxylic acid

(±)-3,3′4,4′-Tetramethyl-1,1′-diphosphaferrocene-2-carboxylic acid 1 was resolved via diastereomeric salts with brucine. The (R)-absolute configuration of (+)-1 was determined by X-ray crystallography.     

Syntheses and characterization of two new compounds based on versatile 1,2,3,5-benzenetetracarboxylic acid and 2,2′-bibenzimidazole

Two coordination complexes based on H₄btec and H₂bibzim (H₄btec = 1,2,3,5-benzenetetracarboxylic acid, H₂bibzim = 2,2′-bibenzimidazole), [Ni(H₂bibzim)₃]₂(btec) (1) and [Zn(H₂bibzim)(btec)_0.5]_n (2), have been synthesized by hydrothermal methods and characterized by single-crystal X-ray diffraction. Complex 1 is composed of [Ni(H₂bibzim)₃]²⁺ with free btec^4? as counter anion. In 2, the btec^4? ligands bridge the Zn(II) ions into a 1-D chain with H₂bibzim as auxiliary chelating ligands. Interesting supramolecular structures were demonstrated due to the existence of hydrogen bonding as well as π?π interactions in the two different complexes. The H₂bibzim ligands act as a 2-connected spacer in both complexes. However, in 1, the [Ni(H₂bibzim)₃]²⁺ cations act as 3-connected nodes, hydrogen bonded with the 6-connected btec^4? ligands into a 3-D framework with (3,6)-connected topology Schläfli symbol as (4.6.8)(4².6)(4³.6⁴.8⁷.10). As for 2, Zn serves as a 3-connected node with btec^4? as a 6-connected node, leading to a 2D (3,6)-connected hydrogen bonding kgd topology sheet with Schläfli symbol of (4³)²(4⁶.6⁶.8³). Thermal stabilities and photoluminescent properties of 1 and 2 were also studied.     

Stepwise synthesis of two inorganic–organic hybrids based on the manganese monosubstituted Keggin polyanion chains

Two new hybrid compounds based on the manganese monosubstituted Keggin polyanion chains, [H₂bpy][Ag(bpy)]₂[HPMnMo₁₁O₃₉] (1) and [H₂bpy]₂[Hbpy][PMnMo₁₁O₃₉]·H₂O (2), (bpy = 4,4′-bipyridine) have been stepwise synthesized under hydrothermal condition and characterized by elemental analyses, IR spectra, thermogravimetry, and single-crystal X-ray diffraction technique. Structural characterization reveals that although both 1 and 2 contain manganese monosubstituted Keggin polyanion chains, the polyanion chains are not in the full consistent way. In 1, the neighboring manganese monosubstituted Keggin clusters are connected via sharing the para position oxygen atoms of the clusters to form a linear polyanion chain in which the monosubstituted Keggin clusters are further grafted by silver coordination polymer chains forming a 2D network. Whereas the polyanion chain in 2 exhibits a zigzag structure, which is formed by sharing the metaposition terminal oxygen atoms of the clusters, rather than para position terminal oxygen atoms as that in 1. Each zigzag chain contacts with four adjacent chains along four directions through short interspecies contacts, forming a 3D supramolecular framework. The protonated Hbipy⁺ and H₂bipy²⁺ molecules as the counter cations exist in voids of the supramolecular framework in 2. Furthermore, photocatalytic experiments indicate that 1 has good activities for photocatalytic degradation of RhB under UV irradiation.     

Novel Synthesis of Phosphorazolides and Phosplior-Anilidates by Reaction of Trimethylsilylphosphites with 1,1′-Oxalyldiazolides or 1,1′-Oxalyldianilidates

Abstract

Continuing our studies on new reaction of trimethylsilylphosphites 1 we now report the conversion of compounds 1 to the corresponding phosphorazolides or phosphoranilidates by the reaction of readily available trimethylsilylphosphites 1 and 1,l'-oxalyldiazolides or anilidates.     

Electrochemical synthesis and characterization of polydiphenylamine

Electrochemical oxidation of diphenylamine(DPA)in acetonitrile solution producedan adhesive conducting polydiphenylamine(PDPA)film on the electrode,which exhibited multiplecolour variation in a wide range of potential.The polymer was characterized by cyclic voltam-merry,FTIR and ESR.The results indicate that the electropolymerization of diphenylamine per-forms via the 4,4＇C—C phenyl-phenyl coupling mechanism.FTIR,ESR and conductivity mea-surements for the different states of PDPA show that polydiphenylamine can be reversibly dopedand dedoped either chemically or electrochemically.It is evidenced also that there are paramagneticspecies—polarons in PDPA supposed to be the current carrier.     

Synthesis and characterization of novel polyimides based on thiazole-containing diamine

A new kind of aromatic diamine monomer containing thiazole unit,2-amino-5-(4-aminophenyl)-thiazole (AAPT),was synthesized in three steps,starting from 4-nitroacetophenone.A novel thiazole-containing polyimide was prepared via the polycondensation of AAPT with 6FDA by one-step method.The resulting polyimide exhibits excellent solubility,film-forming capability and high thermal resistance.     

Resolution and determination of the absolute configuration of 3,3′,4,4′-tetramethyl-1,1′-diphosphaferrocene-2-carboxaldehyde

Racemic 3,3′,4,4′-tetramethyl-1,1′-diphosphaferrocene-2-carboxaldehyde 1 was resolved via the formation of diastereomeric dioxolanes with (S)-(+)-1-phenyl-1,2-ethanediol. Four stereoisomers were separated by column chromatography. The absolute configuration of one of them (2′′R, 4′′S,1R) was established by X-ray diffraction. Acid hydrolysis of the dioxolanes afforded quantitatively (R)- and (S)-enantiomers of 1. Optical rotatory dispersion (ORD) spectra of both enantiomers are also reported.     

Synthesis and spectral properties of new 3,3’-bis(dipyrrolylmethene) with acetylene spacer

Bis(2,4,7,9-tetramethyl-8-ethyldipyrrolylmethen-3-yl)acetylene dihydrobromide (H₂L·2HBr), new bis(dipyrrolylmethene), in whose molecule dipyrrolylmethene domains were connected through 3,3′-carbon atoms of internal pyrrole nuclei by acetylene spacer, were synthesized by original procedure. The compound was characterized by element analysis, IR, ¹H NMR, and electronic spectroscopy. The comparative analysis of spectral properties shows the reduction of the basicity of H₂L ligand in comparison with the structural analogs, which contain internal methylene spacer. The quantum-chemical simulation showed that the rigid acetylene spacer gives linear structure to the H₂L molecule in contrast to the spiral-shaped geometry of structural analogs with -CH₂- spacer.