Synthesis,characterization, antifungal,antibacterial, and antitumor activities of some tris(pentafluorophenyl)arsenic(V) derivatives

A series of tris(pentafluorophenyl) arsenic(V) derivatives of the type (C₆F₅)₃AsL₂, (C₆F₅)₃As(Cl)(L) [L =  OCOC₆H₄(o‐OH),  OCOC‐(OH)(C₆H₅)₂, and 2‐(6‐OCH₃C₁₀H₆)CH(CH₃) COO ], and cycloarsenates, (R = C₆H₅, p‐CF₃C₆H₄, and p‐OCH₃C₆H₄) have been isolated and characterized by elemental analysis and spectroscopic data (infrared; ¹H, ¹⁹F, and ¹³C NMR). These compounds were screened for their in vitro antifungal, antibacterial, and antitumor activities and were found to show moderate to significant activity. © 2010 Wiley Periodicals, Inc. Heteroatom Chem 21:181–187, 2010; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20593     

Bioactive Heteroleptic Bismuth(V) Complexes: Synthesis,Structural Analysis and Binding Pattern Validation

Heteroleptic triorganobismuth (V) complexes of general formula, R₃Bi(OOCR')₂ ( 1 – 7 ), where R = C₆H₅ ( 1 – 3 ), p‐CH₃C₆H₄ ( 4 – 7 ) and R' = 3,5‐Cl₂C₆H₃ ( 1 , 5 ); 3,4,5‐(OCH₃)₃C₆H₂ ( 2 , 6 ); 3‐CH₃C₆H₄ ( 3 , 7 ); 2‐OH‐3‐OCH₃C₆H₃ ( 4 ) have been synthesized and fully characterized by FT‐IR, ¹H &¹³C NMR spectroscopy, single crystal X‐ray crystallography and elemental analysis. The molecular geometry observed for the compounds is predominantly distorted trigonal bipyramidal, the fact which was subsequently authenticated through X‐ray analyses for ( 1 – 4 ). All the synthesized compounds have been bio‐assayed for antileishmanial (Leishmania tropica KWH23) and Jack beans urease inhibitory activity, and human Lymphocytes were used to measure the general toxicity. Of these, ( 4 ) proved to be highly effective against the target species (Leishmania tropica KWH23), while being non‐toxic towards the mammalian cells at levels below 0.74 μgmL^?1, making it highly promising drug candidate. The high activities for ( 2 , 4 , and 6 ) against Jack beans Urease as compared to the reference standard demonstrate their significance in searching of therapeutic agents in future programs. The significant binding score of ( 2 & 4 ) against H. pylori in molecular docking studies further revealed their importance in future drug discovery processes.     

Benchmarking of DFT functionals for the kinetics and mechanisms of atmospheric addition reactions of OH radicals with phenyl and substituted phenyl‐based organic pollutants

^•OH addition reactions play a pivotal role in the atmospheric transformation of a number of phenyl and substituted phenyl‐based persistent and toxic organic pollutants. Here, we screened appropriate DFT functionals to predict reaction mechanisms and rate constants (k_OH) of the ^•OH additions by taking benzene and substituted benzenes (C₆H₅F, C₆H₅Cl, C₆H₅Br, C₆H₅CH₃, C₆H₅OH) as model compounds. By comparing the k_OH values calculated with DFT methods to experimental values, we found that the ωB97 functional is the best among the 18 functionals considered (using the basis sets 6‐31 + G(d,p) for optimizations and 6‐311++G(3df,2pd) for single point energy calculations) in the temperature range of 230‐330 K. In addition, we found that some other functionals performed well in specific conditions, e.g., BMKD3 is good for benzene, halogenated benzenes and C₆H₅CH₃, and CAM‐B3LYP is good for the reaction of C₆H₅OH at room temperature. Based on the diversity of the electronic structures of the selected model compounds and the frequent occurrence of certain substituents ( CH₃,  OH,  F,  Cl, and  Br) in the target compounds, the functionals recommended here can be used for future study of the reaction mechanisms and k_OH values for ^•OH addition to phenyl and substituted phenyl‐based persistent and toxic organic pollutants.     

Synthesis,characterization and antileishmanial studies of some bioactive heteroleptic pentavalent antimonials

In pursuit of safe drug candidates for the treatment of parasitic diseases like leishmaniasis, a series of heteroleptic pentavalent antimonials of the type [R₃Sb(O₂CR′)₂] ( 1 – 9 ) have been synthesized and characterized using elemental analysis (CHN), Fourier transform infrared spectroscopy and multinuclear (¹H and ¹³C) NMR spectroscopy. The carboxylates studied are predominantly substituted benzoates with some complexes having acetato or nicotinato ligands. The crystal structures of [Sb(C₆H₅)₃(o ‐NH₂C₆H₄COO)₂] ( 1 ) and [Sb(C₆H₅)₃(3,5‐Cl₂C₆H₃COO)₂] ( 4 ) were determined as essentially monomeric with an Sb(V) centre and shown to adopt geometries intermediate between trigonal bipyramidal and square pyramidal. The antileishmanial activity was assessed against Leishmania tropica KWH23, and also human macrophages were used to measure the cytotoxicity of these complexes. The IC₅₀ of the antimonials 1 – 9 indicates their efficaciousness as compared with the standard antimonial drug used. The significant activity of complex 1 assumes that greater multitude of interactions is the cause of enhanced antileishmanial activity. Cytotoxicity results showed that these antimonials are highly active even at low concentrations and are biocompatible with human macrophages, making them promising drug candidates for further investigations in this field.     

Complexes of nickel(II) carboxylates with pyridine and cyclam: crystal structures,mesomorphisms, and thermoelectrical properties

Nickel(II) carboxylates [Ni(CH₃(CH₂)₁₄COO)₂(H₂O)₂] (1) and [Ni(C₆H₅COO)₂(H₂O)₂] (2) were obtained from reactions of NiCl₂·6H₂O with CH₃(CH₂)₁₄COONa and C₆H₅COONa, respectively. Complex 1 reacted with pyridine (pyr) to form [Ni(CH₃(CH₂)₁₄COO)₂(pyr)₂(H₂O)₂] (3) and [Ni₂(μ₂-H₂O)(CH₃(CH₂)₁₄COO)₄(pyr)₄] (4) in the same reaction mixture, and reacted with cyclam to form an ionic complex, [Ni(CH₃(CH₂)₁₄COO)(cyclam)(H₂O)]CH₃(CH₂)₁₄COO·4H₂O (5). In contrast, 2 reacted with cyclam to form [Ni(C₆H₅COO)₂(cyclam)] (6). Finally, 6 reacted with p-(hexadecyloxy)pyridine (L) to form an ionic complex, [Ni(cyclam)(L)₂](C₆H₅COO)₂ (7). Complexes 3–6 were single crystals. All complexes have octahedral Ni(II) center(s) and were magnetic. Complexes with cyclam as co-ligand were more thermally stable than those with pyridine and its derivative, L. Complexes 3 and 4 were mesomorphic after partial loss of water and/or pyridine ligands on heating. The ionic complexes 5 and 7 were not mesomorphic, but showed good thermoelectrical behavior with negative S_e values in CHCl₃ (?0.28 mV K^?1 for 5; -0.39 mV K^?1 for 7) and positive S_e values in C₂H₅OH (+0.25 mV K^?1 for 5; +0.20 mV K^?1 for 7).     

Synthesis and biological study of a new series of bifunctional organoiron thio‐ and seleno‐terephthalate derivatives (C5H5)Fe(CO)2ECO(C6H4)COX (E = S,X = R2N,RNH, NH2, OH,Cl; E = Se,X = RNH,RS, RCOO,NH2, OH,Cl)

A new series of bifunctional organoiron thio‐ and seleno‐terephthalate complexes — (η‐C₅H₅)Fe(CO)₂ECO(C₆H₄)COX [E = S; X = C₆H₁₁NH, (C₂H₅)₂N; and E = Se; X = P? CH₃? C₆H₄? NH, C₆H₅? C₂N₂O? S, m? NO₂? C₆H₄? CH?CH? COO] — has been synthesized via the organic transformation reactions of the terephthaloyl chloride precursors η‐(C₅H₅)Fe(CO)₂ECO(C₆H₄)COCl with the desired nucleophiles. These new complexes were characterized by elemental analysis, IR and ¹H NMR spectra. The above complexes, in addition to some other selected analogues, were tested for their antifungal, antibacterial and mutagenic activity. Our results show that all the selenium‐containing compounds have antifungal activity on Candida albicans and antibacterial effects against Bacillus subtilis and Staphylococcus aureus. Four of the six selenium‐containing derivatives exhibited growth inhibitory effects against Pseudomonas aeruginosa and/or Escherichia coli. Sulfur‐containing derivatives elicited activity against C. albicans, and each one of them showed activity against at least one of the bacterial strains that have been used in this investigation. Two selenium‐ and two sulfur‐containing derivatives showed mutagenic activity against one or more than one strain of the Salmonella typhimurium using the Ames test. Copyright © 2001 John Wiley & Sons, Ltd.     

Tris‐Functionalized Hybrid Anderson Polyoxometalates: Synthesis,Characterization, Hydrolytic Stability and Inversion of Protein Surface Charge

Single‐ and double‐sided functionalized hybrid organic–inorganic Anderson polyoxomolybdates with Ga^III and Fe^III positioned as central heteroatoms have been synthesized in a mild, two‐step synthesis in an aqueous medium. Compounds 1 – 4 were isolated as hydrated salts, [TBA]₃[GaMo₆O₁₈(OH)₃{(OCH₂)₃CCH₂OH}]×12 H₂O ( 1 ) (TBA=tetrabutylammonium), Na₃[FeMo₆O₁₈{(OCH₂)₃CCH₂OH}₂]×11 H₂O ( 2 ), [TMA]₂[GaMo₆O₁₈(OH)₃{(OCH₂)₃CNH₃}]×7 H₂O ( 3 ) (TMA=tetramethylammonium), and Na[TMA]₂[FeMo₆O₁₈(OH)₃{(OCH₂)₃CNH₃}](OH)×6 H₂O ( 4 ). All the compounds were characterized based on single‐crystal X‐ray diffraction (SXRD), FTIR, UV/Vis, thermogravimetric, ESI‐MS, NMR, and elemental analyses. Compound 1 was also crystallized with two smaller organic cations, giving [TMA]₃[GaMo₆O₁₈(OH)₃{(OCH₂)₃CCH₂OH}]×n H₂O ( 5 ) and [GDM]₃[GaMo₆O₁₈(OH)₃{(OCH₂)₃CCH₂OH}]×n H₂O ( 6 ) (GDM=guanidinium) and were characterized based on UV/Vis, NMR, FTIR, and elemental analyses. The use of these compounds as additives in macromolecular crystallography was investigated by examining their hydrolytic stability by using ESI‐MS in a pH range of 4 to 9. Sodium dodecyl sulfate‐polyacrylamide gel electrophoresis (SDS‐PAGE) analysis showed that BSA remains intact in a solution containing up to 100 equivalents of 1 or 4 over more than four days at 20 °C. Zeta potential measurements demonstrate that 1 – 4 induce charge inversions on the positively charged surface of BSA (1 mg mL^?1) with concentrations starting as low as 1.29 mM for compounds 1 and 2 , which have the highest negative surface charge.     

Pd(II) complexes of Schiff bases and their application as catalysts in Mizoroki–Heck and Suzuki–Miyaura cross‐coupling reactions

Schiff bases of 2‐(phenylthio)aniline, (C₆H₅)SC₆H₄N?CR (R = (o‐CH₃)(C₆H₅), (o‐OCH₃)(C₆H₅) or (o‐CF₃)(C₆H₅)), and their palladium complexes (PdLCl₂) were synthesized. The compounds were characterized using ¹H NMR and ¹³C NMR spectroscopy and micro analysis. Also, electrochemical properties of the ligands and Pd(II) complexes were investigated in dimethylformamide–LiClO₄ solution with cyclic and square wave voltammetry techniques. The Pd(II) complexes showed both reversible and quasi‐reversible processes in the ?1.5 to 0.3 V potential range. The synthesized Pd(II) complexes were evaluated as catalysts in Mizoroki–Heck and Suzuki–Miyaura cross‐coupling reactions. Copyright © 2015 John Wiley & Sons, Ltd.     

Synthesis and Structure of Lanthanide Sandwich Complexes with Mixed Cyclooctatetraenyl and Chelating Substituted‐indenyl Ligands

Two types of sandwich complexes (η⁵‐MeOCH₂CH₂C₉H₆) Ln (η⁸‐C₈H₈) (THF)_n [Ln=La (1), Nd(2), n=0; Sm(3), Dy (4) and Er (5). n = l] and (η⁵‐C₄H₇OCH₂C₉H₆)Ln(η⁸‐C₈H₈) (THF) [Ln = La (6), Nd(7). Sm(8). Dy (9) and Er (10)] were synthesized by the reactions of LnCl₃ with equivalent mole of K₂C₈H₈, followed by treatment with corresponding potassium salt of ether‐substituted indenide. The molecular structures of 3 and 8 were determined by single crystal X‐ray diffraction. (η⁵ ‐MeOCH₂CH₂C₉H₆) Sm (η⁸‐C₈H₈) (THF) (3) monoclinic. Pt₁/c, a = 1.4793(3) nm, b = 0.8716 (2) nm, c = 1.6149 (3) nm, β = 98. 17(3), V = 2.0612(7) nm³, Z = 4, R(F)=0.0362. (η⁵‐C₄H₇OCH₂C₉H₆)Sm(η⁸‐C₈H₈)(THF) (8) orthorhombic. p2₁2₁2₁. a = 0.8754(2) nm, b = 1.1000(2) nm, c = 2.3117 (5) nm, V = 2.2260(8) nm³, Z=4, R(F) =0.0497.     

Microwave assisted synthesis of disubstituted benzyltin arylformylhydrazone complexes: anticancer activity and DNA‐binding properties

Eight disubstituted benzyltin complexes, i.e., {[R(O)C=N‐N=C (Me)COO]R'₂Sn(CH₃OH)}_n ( 1a and 2b ), {[R(O)C=N‐N=C (Me)COO]R'₂Sn(CH₃OH)}₂ ( 1b and 1d ) and {[R(O)C=N‐N=C (Me)COO]R'₂Sn}_n ( 1c , 2a , 2c , and 2d ) (R = C₄H₃O‐, C₄H₃S‐, p–t‐Bu‐C₆H₄‐ or p‐MeO‐C₆H₄‐; R' = o‐Cl‐C₆H₄CH₂‐ or o‐Me‐C₆H₄CH₂‐), were prepared from the reaction of arylformylhydrazine, pyruvic acid and disubstituted benzyltin dichloride with microwave irradiation. All complexes were characterized by FT‐IR spectroscopy, ¹H, ¹³C and ¹¹⁹Sn NMR spectroscopy, HRMS, elemental analysis, X‐ray single‐crystal diffraction and TGA. The in vitro antitumour activities of all complexes were evaluated by an MTT assay against three human cancer cell lines (NCI‐H460, HepG2, and MCF7). 2b exhibited strong antitumour activity on HepG2 cells and was expected to be a suitable platform for further chemical optimization to develop as anticancer therapeutics. The DNA binding of 2b was studied by UV–visible absorption spectrometry, fluorescence competitive assays, viscosity measurements and gel electrophoresis. Molecular docking was used to predict the binding between 2b and DNA, and the results show that 2b can become embedded in the double helix of DNA and cleave DNA.     

Olefin polymerization and copolymerization with soluble transition‐metal complex catalysts

Olefin polymerizations catalyzed by Cp′TiCl₂(O‐2,6‐ⁱPr₂C₆H₃) ( 1 – 5 ; Cp′ = cyclopentadienyl group), RuCl₂(ethylene)(pybox) { 7 ; pybox = 2,6‐bis[(4S)‐4‐isopropyl‐2‐oxazolin‐2‐yl]pyridine}, and FeCl₂(pybox) ( 8 ) were investigated in the presence of a cocatalyst. The Cp*TiCl₂(O‐2,6‐ⁱPr₂C₆H₃) ( 5 )–methylaluminoxane (MAO) catalyst exhibited remarkable catalytic activity for both ethylene and 1‐hexene polymerizations, and the effect of the substituents on the cyclopentadienyl group was an important factor for the catalytic activity. A high level of 1‐hexene incorporation and a lower r_E · r_H value with 5 than with [Me₂Si(C₅Me₄)(N^tBu)]TiCl₂ ( 6 ) were obtained, despite the rather wide bond angle of Cp Ti O (120.5°) of 5 compared with the bond angle of Cp Ti N of 6 (107.6°). The 7 –MAO catalyst exhibited moderate catalytic activity for ethylene homopolymerization and ethylene/1‐hexene copolymerization, and the resultant copolymer incorporated 1‐hexene. The 8 –MAO catalyst also exhibited activity for ethylene polymerization, and an attempted ethylene/1‐hexene copolymerization gave linear polyethylene. The efficient polymerization of a norbornene macromonomer bearing a ring‐opened poly(norbornene) substituent was accomplished by ringopening metathesis polymerization with the well‐defined Mo(CHCMe₂Ph)(N‐2,6‐ⁱPr₂C₆H₃)[OCMe(CF₃)₂]₂ ( 10 ). The key step for the macromonomer synthesis was the exclusive end‐capping of the ring‐opened poly(norbornene) with p‐Me₃SiOC₆H₄CHO, and the use of 10 was effective for this polymerization proceeding with complete conversion. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 4613–4626, 2000     

The psuedo‐michael reaction of 2‐aminoimidazolines 2. Part 1. Synthesis and structure assignment of isomeric 5(1H)‐Oxo and 7(1H)‐Oxo‐2,3‐dihydroimidazo[1,2‐a]pyrimidine‐6‐carboxylates

The pseudo‐Michael reaction of 1‐aryl‐2‐aminoimidazolines‐2 with diethyl ethoxymethylenemalonate (DEEM) was investigated. Extensive structural studies were performed to confirm the reaction course. For derivatives with N1 aromatic substituents, it was found that the reaction course was temperature dependent. When the reaction temperature was held at ?10 °C only the formation of 1‐aryl‐7(1H)‐oxo‐2,3‐dihydroimi‐dazo[1,2‐a]pyrimidine‐6‐carboxylates ( 4 ) was observed in contrast to earlier suggestions. Under the room temperature conditions, the same reaction yielded mixtures, with varying ratio, of isomeric 1‐aryl‐7(1H)‐oxo‐ ( 4a‐4f ) and 1‐aryl‐5(1H)‐oxo‐2,3‐dihydroimidazo[1,2‐a]pyrimidine‐6‐carboxylates ( 5a‐5f ). The molecular structure of selected isomers, 4b and 5c , was confirmed by X‐ray crystallography. Frontal chro‐matography with delivery from the edge was applied for the separation of the isomeric esters. The isomer ratio of the reaction products depended on the character of the substituents on the phenyl ring. The 1‐aryl‐7(1H)‐oxo‐carboxylates ( 4a‐4f ) were preferably when the phenyl ring contained H, 4‐CH₃, 4‐OCH₃ and 3,4‐Cl₂ substituents. Chloro substitution at either position 3 or 4 in the phenyl ring favored the formation of isomers 5a‐5f . The isomer ratios were confirmed both by ¹H NMR and chromatography. The reaction of the respective hydrobromides of 1‐aryl‐2‐aminoimidazoline‐2 with DEEM, in the presence of triethylamine, gave selectively 5(1H)‐oxo‐esters ( 5a‐5f ).     

Synthesis,characterization, X‐ray crystal structure and in vitro antitumour activity of sodium bis(2‐(3′,6′,9′‐trioxadecyl)‐1,2‐dicarba‐closo‐dodecaborane‐1‐carboxylato)triphenylstannate

Sodium bis[2‐(3′,6′,9′‐trioxadecyl)‐1,2‐dicarba‐closo‐dodecaborane‐1‐carboxylato]triphenylstannate, [(CH₃OCH₂CH₂OCH₂CH₂OCH₂CH₂)‐1,2‐C₂B₁₀H₁₀‐9‐COO)₂SnPh₃]^? Na⁺, compound 1, was synthesized by the 1:1 condensation of triphenyltin(IV) hydroxide with 2‐(3′,6′,9′‐trioxadecyl)‐1,2‐dicarba‐closo‐dodecaborane‐1‐carboxylic acid and crystallized in the presence of sodium bicarbonate. Its structure was determined by spectroscopy, elemental analysis and X‐ray diffraction. The structure of 1 consists of trigonal bipyramidal [Sn(Ph)₃(L)₂]^? anions and Na⁺ cations coordinated by oxygen atoms of polyoxaalkyl chains of different stannate anions, forming cation–anion chains elongated along the c axis. Compound 1 is significantly more active in vitro against seven tumour cell lines of human origin than 5‐fluorouracil, cis‐platin, carboplatin, and previously reported organotin carboranecarboxylates, but is less active than organotin polyoxaalkylcarboxylates. Copyright © 2004 John Wiley & Sons, Ltd.     

Synthesis,crystal structure and cytotoxic activity of tricyclohexyltin complexes of benzenedioxyacetic acids

Two new bis(tricyclohexyltin)benzenedioxyacetates, 1,x‐C₆H₄[OCH₂CO₂Sn(c‐C₆H₁₁)₃]₂ ( 1 : x = 3; 2 : x = 4), have been synthesized and characterized by means of elemental analysis, infrared and NMR (¹H, ¹³C and ¹¹⁹Sn) spectra and single‐crystal X‐ray diffraction. Compound 1 ?H₂O?CH₃OH is a binuclear tin complex containing a four‐coordinated tin and a five‐coordinated tin and linked by an R₃³(16) hydrogen bond into a one‐dimensional supramolecular chain. Compound 2 is a two‐dimensional coordination polymer which is formed as a result of anisobidentate bridging coordination action of the two carboxylate units of the ligand. Interestingly the two‐dimensional coordination polymer contains 34‐membered macrocycles each of which is comprised of four tricyclohexyltin units. Both compounds have potent in vitro cytotoxic activity against three human tumor cell lines: HeLa, MCF‐7 and CoLo 205. Copyright © 2015 John Wiley & Sons, Ltd.     

Synthesis,Structure, and Reactivity of RuII Complexes with Trimethylsilylethinylamidinate Ligands

The mononuclear amidinate complexes [(η⁶‐cymene)‐RuCl( 1a )] ( 2 ) and [(η⁶‐C₆H₆)RuCl( 1b )] ( 3 ), with the trimethylsilyl‐ethinylamidinate ligands [Me₃SiC≡CC(N‐c‐C₆H₁₁)₂]^– ( 1a^– ) and[Me₃SiC≡CC(N‐i‐C₃H₇)₂]^– ( 1b^– ) were synthesized in high yields by salt metathesis. In addition, the related phosphane complexes[(η⁵‐C₅H₅)Ru(PPh₃)( 1b )] ( 4a ) [(η⁵‐C₅Me₅)Ru(PPh₃)( 1b )] ( 4b ), and [(η⁶‐C₆H₆)Ru(PPh₃)( 1b )](BF₄) ( 5 ‐BF₄) were prepared by ligand exchange reactions. Investigations on the removal of the trimethyl‐silyl group using [Bu₄N]F resulted in the isolation of [(η⁶‐C₆H₆)Ru(PPh₃){(N‐i‐C₃H₇)₂CC≡CH}](BF₄) ( 6 ‐BF₄) bearing a terminal alkynyl hydrogen atom, while 2 and 3 revealed to yield intricate reaction mixtures. Compounds 1a / b to 6 ‐BF₄ were characterized by multinuclear NMR (¹H, ¹³C, ³¹P) and IR spectroscopy and elemental analyses, including X‐ray diffraction analysis of 1b , 2 , and 3 .     

Poly(ethylene terephthalate) synthesis catalysed by chelated Sn,Zn and Mg complexes

A series of four C,N‐chelated diorganotin(IV) compounds, namely (L^CN)₂Sn(OCH₂CH₂O) ( 1 ), [L^CNBuSn(OCH₂CH₂O)]₂ ( 2 ), (L^CN)₂Sn(1,2‐(O)₂‐3,5‐tBu₂C₆H₂) ( 3 ) and [L^CNBuSn(1,2‐(O)₂‐3,5‐tBu₂C₆H₂)]₂ ( 4 ) (L^CN = 2‐(Me₂NCH₂)C₆H₄), one zinc species, namely L^NOZnEt ( 5 ) (L^NO = [2‐(MeO)C₆H₄]NC(Me)?C(H)C(Me)?O), and one magnesium complex, namely [L^NNMg]₆ ( 6 ), (L^NN = [2‐(Me₂NCH₂)C₆H₄]N), were used as catalysts for the synthesis of poly(ethylene terephthalate) (PET) from dimethyl terephthalate and ethylene glycol. Prepared PET samples were primarily characterized using the size exclusion chromatography technique. The highest number‐average molar mass of prepared PET samples reached 10.7 kg mol^?1. Novel dimeric compound 2 was structurally characterized using both multinuclear NMR spectroscopy and X‐ray diffraction analysis. In addition, an alternative synthesis of 1 is described. Copyright © 2015 John Wiley & Sons, Ltd.     

Ru and Sm catalyzed polyaddition of dialdehydes to give polyesters. Application of Tishchenko type reactions to polymer synthesis

RuH₂(PPh₃)₄ catalyzed Tishchenko type polyaddition of terephthal-aldehyde gives aromatic polyester ( 1 ), which contains three structural units, [OCH₂ C₆H₄ CH₂O] ( 1a ), [OCH₂ C₆H₄ CO] ( 1b ), and [CO C₆H₄ CO] ( 1c ). ¹H-NMR spectrum shows the presence of the three units in a 1 : 2 : 1 ratio. Isophthalaldehyde also undergoes similar polyaddition to give another aromatic polyester ( 2 ), while 1,12-dodecanedial gives an aliphatic polyester ( 3 ) containing the following structural units: [OCH₂ (CH₂)₁₀ CH₂O] ( 3a ), [OCH₂ (CH₂)₁₀ CO] ( 3b ), and [CO (CH₂)₁₀ CO] ( 3c ). The above polymers have M_n of 2.7 × 10³−5.4 × 10³ and M_w of 4.3 × 10³ − 9.7 × 10³, respectively. Mixtures of terephthalaldehyde and 1,12-dodecanedial produce copolymers, which contain the units 1a–1c and 3a–3c in a random sequence. In the copolymerization, terephthalaldehyde shows a strong tendency to give 1c units, whereas 1,12-dodecanedial predominantly affords 3a units. SmI₂ also catalyzes polyaddition of terephthalaldehyde to give the corresponding polyester with M_n of 1.7 × 10³ and M_w of 3.7 × 10³, respectively. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 1265–1273, 1997     

Electrospray ionization mass spectrometry of tributyltin(IV) complexes and their larvicidal activity on mosquito larvae: crystal and molecular structure of polymeric (Bu3Sn[O2CC6H4{NN(C6H3‐4‐OH(C(H)NC6H4OCH3‐4))}‐o])n

A series of tributyltin(IV) complexes of 2‐[(E)‐2‐(3‐formyl‐4‐hydroxyphenyl)‐1‐diazenyl]benzoic acid and 4‐[((E)‐1‐{2‐hydroxy‐5‐[(E)‐2‐(2‐carboxyphenyl)‐1‐diazenyl]phenyl}methylidene)amino]aryls have been investigated by electrospray mass spectrometry (ESI‐MS) and tandem mass spectrometry (MSⁿ) techniques. The assignments are facilitated by agreement between observed and calculated isotopic patterns and MSⁿ studies. Single‐crystal X‐ray crystallography of (Bu₃Sn[O₂CC₆H₄{N?N(C₆H₃‐4‐OH(C(H)?NC₆H₄OCH₃‐4))}‐o])_n reveals a polymeric structure. Toxicity studies of the tributyltin(IV) complexes of the 4‐[((E)‐1‐{2‐hydroxy‐5‐[(E)‐2‐(2‐carboxyphenyl)‐1‐diazenyl]phenyl}methylidene)amino]aryls on the second larval instar of the Aedes aegypti and Anopheles stephensi mosquito larvae are also reported. The LC₅₀ values indicate that the complexes are effective larvicides, which range from a low of 0.36 ppm to a high of 0.69 ppm against the Ae. aegypti larvae and between 0.82 and 1.17 ppm against the An. stephensi larvae. Copyright © 2005 John Wiley & Sons, Ltd.     

Improved synthesis of cyclic and polymeric phosphazenes based on facile chlorine substitution with phenols promoted by cesium carbonate

In this report we describe a very convenient synthetic method for the preparation in high yields and purity of cyclic [N₃P₃(OCH₂CF₃)₆] and [N₃P₃(OC₆H₄R)₆] (R = Br, CN, CHO, COC₆H₅, COCH₃, H, OCH₃), and polymeric [NP(OC₆H₄R)₂]_n (R = Br, CHO, COC₆H₅, H, Bu^t) phosphazenes from the direct reaction of the trimer [N₃P₃Cl₆] or the high polymer [NPCl₂]_n and the alcohol HO CH₂CF₃ or the para-substituted phenols HO C₆H₄R, using Cs₂CO₃ as proton abstractor and acetone or tetrahydrofuran as solvent.     

Supramolecular hexagonal structure of a segmented liquid crystalline polyester with allyl group as lateral substituent

The molecular structure of the phase—stable at room temperature—for the polymer with formula [ p C₆H₄ COO p C₆H₃(R) p C₆H₃(R) OOC p C₆H₄ O (CH₂)₁₀O ]_x, with R =  CH₂ CHCH₂, is reported. The cell is hexagonal (a = b = 13.43 Å, c = 33.3 Å, γ = 120°), space group P6₃, six chains per unit cell (d_calcd = 1.23 g cm⁻³). The six chains are packed together to give a bundle with the center of mass set at the origin of the unit cell. The allyl groups are placed inside the bundle, thus explaining the unexpected reactivity of the double bonds to give crosslinking when fiber samples are annealed in the solid state. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 1601–1607, 1999