KINETICS OF NON-ISOTHERMAL CRYSTALLIZATION OF POLY (ETHYLENE TEREPHTHALATE) MODIFIED BY POLY (ETHYLENE GLYCOL)

The non-isothermal crystallization kinetics of poly(ethylene terephthalate) (PET) modified by poly (ethlene glycol) (PEG) were determined by DSC. The dual linear regression method was used to evaluate the relationship between the reciprocal of t 1/2 ( the half life of crystallization) and the appropriate temperature variable. The parameters such as the activation energy (Ed) for transport, the equilibrium melting temperature (T_m~0),the nucleation parameter (ψ),themaximum crystallization temperature (T_(e, max)), and the kinetic crystallizability (G) for the copolyesters were obtained. The influence of the PEG content in PET chains on the parameters characterizing crystallization kinetics and crystallization thermodynamics was discussed.     

Synthesis and Molecular Structure of Binuclear Tin（Ⅳ）Complex Bridged by Terephthalate Anion

The title complex [Ph₃Sn(CH₃OH) (terephthalate) (CH₃OH) SnPh₃]·2CH₃OH was synthesized by the reaction of Ph₃SnCl with terephthalate in the molar ratio of 2:1 in methanol solution and characterized by elemental analysis, IR and ¹H NMR spectra, and the crystal structure was determined by X‐ray single crystal diffraction study. The crystal belongs to monoclinic with space group P2₁/n, a = 1.5199(5) nm, b = 0.9000(3) nm, c = 1.8206(6) nm, β= 113.970(5)°, Z = 2, V = 2.2755 (13) nm³, D_c= 1.413 g/cm³, μ = 1.146 mm^?1, F(000) = 980, R =0.0353, wR = 0.0606. In the crystals of complex, the tin atoms rendered five‐coordinate in a distorted trigonal bipyramidal structure.     

Synthesis and Characterization of New Schiff Bases 2-(2-(2-(Aryl)Methyleneamino)Phenylthio) Ethylthio)-N-((aryl)Methylene)Benzeneamine

A series of Schiff bases containing four to six coordination sites N₂S₂ X₂(X = O,N) 2-(2-(2-(aryl)methyleneamino)phenylthio)ethylthio)-N-((aryl)methylene)benzeneamine (2c–f) were prepared from the reaction of 1,2-di(2-aminophenylthio)ethane (1) with aromatic aldehydes. All compounds were characterized by means IR, mass, ¹H and ¹³C NMR spectroscopy, and elemental analysis, and in the case of 2b with a single crystal X-ray diffraction. The X-ray crystal structure of 2b showed that the resonance occurs between aromatic rings, through the C=N bonds of the molecule.

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.     

SYNTHESIS OF POLY(ETHYLENE TEREPHTHALATE)-POLYCAPROLACTONE BLOCK COPOLYMER BY DIRECT COPOLYMERIZATION*

Poly(ethylene terephthalate) -polycaprolactone block copolymer (PCL- b-PET) is a polyester withimproved biodegradability. In the present paper, a new direct copolymerization method of ε-caprolactone (ε-CL) and bishydroxyethylene terephthalate (BHET) in the presence of Ti(OBu)_4 was proposed for thesynthesis of PCL-b-PET. The PCL-b-PET copolymer was characterized by IR, GPC and ~1H-NMRtechniques, and the effects of synthesis conditions, such as temperature, reaction time and concentration ofcatalyst on the copolymerization were discussed.     

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.     

Poly(ethylene terephthalate) copolymers containing nitroterephthalic units. III. Methanolytic degradation

The methanolytic degradation of poly(ethylene terephthalate) (PET) copolymers containing nitroterephthalic units was investigated. Random poly(ethylene terephthalate‐co‐nitroterephthalate) copolyesters (PETNT) containing 15 and 30 mol % nitrated units were prepared from ethylene glycol and a mixture of dimethyl terephthalate and dimethyl nitroterephthalate. A detailed study of the influence of the nitro group on the methanolytic degradation rate of the nitrated bis(2‐hydroxyethyl) nitroterephthalate (BHENT) model compound in comparison with the nonnitrated bis(2‐hydroxyethyl) terephthalate (BHET) model compound was carried out. The kinetics of the methanolysis of BHENT and BHET were evaluated with high‐performance liquid chromatography and ¹H NMR spectroscopy. BHENT appeared to be much more reactive than BHET. The methanolytic degradation of PET and PETNT copolyesters at 80 °C was followed by changes in the weight and viscosity, gel permeation chromatography, differential scanning calorimetry, scanning electron microscopy, and ¹H and ¹³C NMR spectroscopy. The copolyesters degraded faster than PET, and the degradation increased with the content of nitrated units and occurred preferentially by cleavage of the ester groups placed at the meta position of the nitro group in the nitrated units. For both PET and PETNT copolyesters, an increase in crystallinity accompanied methanolysis. A surface degradation mechanism entailing solubilization of the fragmented polymer and consequent loss of mass was found to operate in the methanolysis of the copolyesters. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2276–2285, 2002     

Chemie polyfunktioneller Moleküle. 116. Hydrido-, Deuterido-, Thiolato- und Chlororuthenium(II)-Komplexe des Bis(diphenylphosphino)amins

Chemistry of Polyfunctional Molecules. 116 Hydrido-, Deuterido-, Thiolato-, and Chlororuthenium(II) Complexes of Bis(diphenylphosphino)amine Bis(diphenylphosphino)amine, [(C₆H₅)₂P]₂NH (dppa, 1 ), reacts with [Ru(cod)(cot)] (cod = η-1,5-cyclooctadiene, cot = η-1,3,5-cyclooctatriene) ( 2 ) in a molar ratio of 2 : 1 both in a hydrogen or deuterium atmosphere at room temperature to yield cis-[Ru(H)₂(dppa)₂] ( 3 ) and cis-[Ru(D)₂(dppa)₂] ( 3 a ), respectively. The dihydride complex 3 is very sensitive towards halogenated solvents: dissolution of 3 in CHCl₃ or CH₂Cl₂ produces the monohydride compound trans-[RuCl(H)(dppa)₂] ( 4 ). Treatment of 3 with a threefold excess of tert-butyl mercaptane, Me₃CSH, at room temperature results in the formation of cis-[Ru(H)(SCMe₃)(dppa)₂] ( 5 ). Trans-[RuCl₂(dppa)₂] ( 7 ) can be synthesized by the interaction of [RuCl₂(PPh₃)₃] ( 6 ) with one or two equivalents of 1 in CH₂Cl₂ solution. The NMR spectra of 3, 3 a, 4, 5 and 7 are discussed with respect to molecular stereochemistry and hydrogen-halogen exchange under simultaneous cis-trans rearrangement. In addition to ¹H, ²H, ³¹P{¹H}, and ³¹P NMR, the structures of the different complexes were also derived from 1R, Raman, and mass spectra. The NMR spectra simulation of 3 permits detailed assignments of spin-spin coupling constants. Crystals of cis-[Ru(H)(SCMe₃)(dppa)₂] ( 5 ) are monoclinic, space group P2₁/c, with a = 1 179.9(3), b = 2 228.0(4), c = 1 854.8(6) pm, β = 96.23(2)°, Z = 4, and R_w = 0.062. The structural analysis shows that ruthenium is coordinated by two bidentate organophosphine ligands and by one tert-butyl thiolate molecule. The metal bound hydrogen atom was not located. However, in agreement with ¹H NMR, its position is trans to a phosphorus nucleus.     

左旋异松蒎酮的合成

研究了以(－)-α-蒎烯为原料合成(－)-异松蒎酮的反应. 以四氢呋喃为溶剂, 硼氢化钠与三氟化硼乙醚溶液生成的硼烷不经分离直接与α-蒎烯发生反马氏加成反应, 生成二异松蒎烷基硼; 采用四水合过硼酸钠或NaOH-H₂O₂氧化硼氢化物得到(＋)-异松蒎醇, 产率为89.5%, 纯度97.4%, 熔点为55～56 ℃, 比旋光度 ＋28.31 (c 5.55, CH₃OH). 以钒磷氧化物为催化剂、双氧水作氧化剂, 将(＋)-异松蒎醇氧化得到(－)-异松蒎酮, 产率88% 以上, 纯度96.0%, 比旋光度为 －10.58 (c 5.51, CH₃OH). 采用IR, MS, ¹H NMR, ¹³C NMR等对(＋)-异松蒎醇和(－)-异松蒎酮结构进行了表征.     

Self-assembly of bis(pyrrol-2-yl-methyleneamine)s bridged by flexible linear carbon chains

Two linear bis(pyrrol-2-yl-methyleneamine)s linked by a carbon chain, -(CH₂)_n-, n=2, 4, were synthesized in high yields by condensation of 2-formylpyrrole with the corresponding diamines. Self-assembly of the resulting bis(pyrrol-2-yl-methyleneamine) ligands with Zn(II) gave double-stranded helicates in excellent yields. Their structures were characterized by MS, ¹H NMR, ¹³C NMR, UV-Vis spectroscopic studies, and were confirmed by an X-ray crystal analysis. In CH₂Cl₂, both complexes 4 and 5 displayed moderate fluorescence.     

Binuclear dichlorido(η6‐p‐cymene)ruthenium(II) complexes with bis(nicotinate)‐ and bis(isonicotinate)‐polyethylene glycol ester ligands

Neutral binuclear ruthenium complexes 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 of the general formula [{RuCl₂(η⁶‐p‐cym)}₂ μ‐(N^∩N)] (N^∩N = bis(nicotinate)‐ and bis(isonicotinate)‐polyethylene glycol esters: (3‐py)COO(CH₂CH₂O)_nCO(3‐py) and (4‐py)COO(CH₂CH₂O)_nCO(4‐py), n =1–4), as well as mononuclear [RuCl₂(η⁶‐p‐cym)((3‐py)COO(CH₂CH₂OCH₃)‐κN)], complex 9 , were synthesized and characterized using elemental analysis and electrospray ionization high‐resolution mass spectrometry, infrared, ¹H NMR and ¹³C NMR spectroscopies. Stability of the binuclear complexes in the presence of dimethylsulfoxide was studied. Furthermore, formation of a cationic complex containing bridging pyridine‐based bidentate ligand was monitored using ¹H NMR spectroscopy. Ligand precursors, polyethylene glycol esters of nicotinic ( L1 · 2HCl– L4 · 2HCl and L9 · HCl) and isonicotinic acid dihydrochlorides ( L5 · 2HCl– L8 · 2HCl), binuclear ruthenium(II) complexes 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 and mononuclear complex 9 were tested for in vitro cytotoxicity against 518A2 (melanoma), 8505C (anaplastic thyroid cancer), A253 (head and neck tumour), MCF‐7 (breast tumour) and SW480 (colon carcinoma) cell lines. Copyright © 2014 John Wiley & Sons, Ltd.     

Isolation and identification of cyclic oligomers of the poly(ethylene terephthalate)–poly(ethylene isophthalate) copolymer

New cyclic oligomers of the copolymer of poly(ethylene terephthalate) (PET) and poly(ethylene isophthalate) (PEI) were isolated and identified. A condensation polymerization was carried out at a high temperature, and the solid‐state polymerization that followed yielded the high molecular weight polymer. The oligomers were extracted from the high molecular weight PET–PEI copolymer and separated with preparative high performance liquid chromatography techniques. Their chemical structures and properties were analyzed and determined by ¹H NMR, differential scanning calorimetry, and mass spectroscopy. The oligomers observed at early retention times were a cyclic dimer and cyclic trimers and consisted of [GT]₃, [GI]₂, [GI]₃, [GT]₂[GI]₁, and [GT]₁[GI]₂. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 881–889, 2003     

First diphosphinoamine ligand bearing a polymerizable side chain: Complexation with copper(I)

A diphosphinoamine ligand with a polymerizable side chain, (PPh₂)₂N? CH₂? C₆H₄? CH?CH₂ (vbzpnp or 1 ), was synthesized. The ligand could be polymerized by anionic polymerization with n‐butyllithium as the initiator. Polyvbzpnp was soluble in tetrahydrofuran and chloroform but was insoluble in methanol and was characterized with NMR, IR, and gel permeation chromatography. The number‐average and weight‐average molecular weights were 40,050 and 55,690, respectively, and the polydispersity index was 1.39. [Cu(CH₃CN)₄]ClO₄ formed a bischelated complex with the monomer and produced [Cu( 1 )₂]ClO₄ ( 2 ), and CuCl formed a tetramer, Cu₄( 1 )₂Cl₄ ( 3 ). All the compounds ( 1 , 2 , and 3 ) were characterized with single‐crystal‐structure determination, NMR, and IR spectroscopy. The addition of [Cu(CH₃CN)₄]ClO₄ to polyvbzpnp resulted in an insoluble crosslinked polymer, which was characterized with solid‐state ³¹P {¹H} magic‐angle‐spinning NMR. The copolymerization of styrene and 1 produced a styrene–vbzpnp copolymer that was found to be soluble in common organic solvents. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 3411–3420, 2005     

SYNTHESIS OF NOVEL BIDENTATE (Te,N) LIGANDS-2-ARYLTELLUROETHYLAMINES AND THEIR COMPLEXATION WITH MERCURY (II)

Abstract

Sodium aryltellurolate (ArTe^?Na⁺, where Ar = 4-MeOC₆H₄ or 4-EtOC₆H₄) reacts with 2- bromoethylamine resulting in the (Te, N) ligands 2-aryltelluroethylamine (ArTeCH₂CH₂NH₂, 1) which have been characterized by elemental analyses, molecular weight, IR, ¹H and ¹³C NMR spectra. With HgCI₂, they form HgC1₂·1 type of complexes. IR, ¹H and ¹³C NMR spectra of the complexes suggest that 1 ligates as a bidentate ligand with respect to Hg(II). Osmometric molecular weight measurements suggest that on heating the mercury complex HgCl₂·lb (Ar = 4-EtOC₆H₄) in solution, relatively less soluble species result. It seems to have two Hg atoms bridged by two (Te, N) ligands. The HgC₂·la (Ar = 4-MeOC₆H₄) has very low solubility in organic solvents and. therefore, seems to be dimerized or polymerized during the synthesis. Analysis of CH₂ rocking bands in IR spectra suggests that two CH₂ groups of the ligands are most probably in a gauche conformation in the mercury complexes.     

Assembly and Dissociation of Α-Cyclodextrin [2]Pseudorotaxanes with α,ω-Bis(N-(N,N′-dimethylethylenediamine)alkane Threads

A series of novel bischelate bridging ligands, CH₃NH(CH₂)₂N(CH₃)(CH₂)_nN(CH₃)(CH₂)₂NHCH₃ (n = 9, 10, 11, and 12) were synthesized as hydrochloride salts and characterized by elemental analyses, electrospray mass spectrometry, and ¹H and ¹³C NMR spectroscopy. These ligands form [2]pseudorotaxanes with α-cyclodextrin (α-CD) and the stability constants have been determined from ¹H NMR titrations in D₂O. The kinetics and mechanism of the assembly and dissociation of a [2]pseudorotaxane in which α-CD has been threaded by the CH₃NH₂(CH₂)₂N(CH₃)(CH₂)₁₂N(CH₃)(CH₂)₂NH₂CH₃²⁺ ligand were determined in aqueous solution using ¹H NMR spectroscopy. A weak inclusion of the dimethylethylenediamine end group precedes the passage of the α-CD onto the hydrophobic dodecamethylene chain.     

[Hg2(μ‐bpe)(μ‐OAc)2(μ‐SCN)2]n,a New Two‐Dimensional Coordination Polymer Involving Three Simultaneously Bridging Ligands: 1,2‐Bis(4‐pyridyle)ethene,Acetate, and Thiocyanate

A new mercury(II) complex of 1,2‐bis(4‐pyridyle)ethene (bpe) with anionic acetate and thiocyanate ligands has been synthesized and characterized by elemental analysis, IR, ¹H NMR and ¹³C NMR spectroscopy. The single crystal X‐ray analysis shows that the complex is a two‐dimensional polymer with simultaneously bridging 1,2‐bis(4‐pyridyle)ethane, acetate and thiocyanate ligands and basic repeating dimeric [Hg₂(μ‐bpe)(μ‐OAc)₂(μ‐SCN)₂] units. The two‐dimensional system forms a three‐dimensional network by packing via π‐π stacking interactions.     

Three‐dimensional Hemidirected Mixed‐ligand Lead(II) Coordination Polymer, [Pb2(bpa)2(SCN)3(NO3)]n (bpa = 1,2‐di(4‐pyridyl)ethane)

A new 3D hemidirected mixed‐ligand lead(II) coordination polymer with the ligand 1,2‐di(4‐pyridyl)ethane bpa) and the two metal coordinated anions nitrate and thiocyanate, [Pb₂(bpa)₂(SCN)₃(NO₃)]_n ( 1 ), has been synthesized and characterized by CHN elemental analysis, IR‐, ¹H‐ and ¹³C NMR spectroscopy. The single crystal X‐ray data of compound 1 show that the complex is a three‐dimensional coordination polymer with two different Pb atoms with stereoactive electron lone pairs and six‐ and five‐coordinate hemidirected geometries, respectively.     

Synthesis and structural study of copolymers of l-lactic acid and bis(2-hydroxyethyl terephthalate)

Poly(ethylene terephthalate)-poly(lactic acid) (PET-PLLA) copolyesters were synthesized by the melt reaction of bis(2-hydroxyethyl terephthalate) (BHET) with l-lactic acid oligomers (OLLA) in the presence of SnCl₂, H₂O-p-toluene sulfonic acid, H₂O catalytic system. The ¹H and ¹³C NMR studies confirm the incorporation of lactate units in PET chains after reaction. Copolyesters containing nearly equimolar terephthalate/lactate ratio are not completely random and present some block-copolymer character, while the microstructure of PET-rich copolyesters is a random one. Due to a longer PET sequence length, the latter exhibit a melting point close to 210 °C while the other ones are amorphous. SEC/MALDI-TOF MS off-line coupling was used to obtain the absolute average molar masses of the copolyesters. The results indicate that the conventional polystyrene calibration method leads to a strong overestimation of PET-PLLA molar masses, while the determined by NMR is much closer to the SEC/MALDI value.     

Nickel(II) complexes with mono(imino)pyrrole ligands: preparation,structure and ethylene polymerization behavior

A series of unsymmetrical mono(imine)pyrroles (L1–L3) were synthesized by microwave irradiation from 2-acetylpyrrole and a series of dimethylanilines with two methyl groups at different positions on the aniline ring. A simplified synthetic method was initiated to prepare the corresponding nickel complexes NiL₂ (1–3) with direct condensation of mono(imine)pyrrole and nickel chloride. The compounds were determined using a suite of techniques (i.e. ¹H NMR, ¹³C NMR, IR, EA, MS). L1–L3 and 3 were further characterized by X-ray crystal diffraction. The structure of 3 showed that the ligand chelated to nickel with 2?:?1 M ratio, in spite of a 1?:?1 rate of charge. Application of 1–3 in ethylene polymerization indicated that mono(imino)pyrrole nickel complexes showed low activities. The polymerization reaction time and temperature, as well as the ligand structure, influenced the catalytic performance to some extent. Experimental data showed higher activity as –CH₃ on the aniline ring is closer to the imine group.     

(Phosphine)gold(I) Complexes of Benzenedithioles. Crystal structures of 1,2-benzenedithiolato-bis[triphenyl-phosphinegold(I)] and bis(triethylphosphine)gold(I) bis(1,2-benzenedithiolato)gold(III)

The reaction of 1,2- and 1,3-benzenedithiol C₆H₄(SH)₂ with chloro(phosphine)gold(I) complexes R₃PAuCl (R = Et, Ph) in the presence of triethylamine in tetrahydrofuran gives stable gold(I) complexes 1,2-C₆H₄(SAuPR₃)₂ [R = Et ( 1 ) and Ph ( 2 )] or 1,3-C₆H₄(SAuPPh₃)₂ ( 3 ), respectively, in high yield. The compounds have been characterized by analytical and NMR spectroscopic data. From the reaction of 1,2-C₆H(SH)₂ with Et₃P? AuCl a by-product [(Et₃P)₂Au]⁺ [Au(1,2? C₆H₄S₂)₂]^? ( 4 ) has also been isolated in low yield. The crystal structures of compounds 2 and 4 have been determined by single crystal X-ray diffraction. The gold(I) atoms in complex 2 are two-coordinate with bond angles S? Au? P of 175.2(1) and 159.5(1)°, Au? S bond distances of 2.304(1) and 2.321(1) å, and a short Au…?Au contact of 3.145(1) Å. The gold(I) atom in the cation of complex 4 is also linearly two-coordinate with a P? Au? P angle of 170.1(1) Å and Au? P distances of 2.296(3) and 2.298(3) Å. The geometry of the anion in 4 shows a square-planar coordination of gold(III) by two chelating 1,2-benzenedithiolate ligands with Au? S distances between 2.299(3) and 2.312(3) Å (for two crystallographically independent, centrosymmetrical anions in the unit cell).     

The Synthesis,Characterization and Conductance Studies of New Cu(II), Ni(Ii) And Zn(II) Complexes with the Schiff Base Derived from 1,2-Bis-(o-Aminophenoxy)Ethane and Salicylaldehyde

Cu(II), Ni(II) and Zn(II) complexes with the Schiff base derived from 1,2-bis-(o-aminophenoxy)ethane with salicylaldehyde have been prepared. The complexes have been characterized by elemental analysis, magnetic measurements, ¹H NMR, ¹³C NMR, UV, visible and IR spectra as well as conductance measurements. The ligand is coordinated to the central metal as a tetradentate ONNO ligand. The four bonding sites are the central azomethine nitrogen and aldehydic OH groups. The ligand was used for complexation studies. Stability constants were measured by a conductometric method. Furthermore, the stability constants for complexation between ZnCl₂ and Cu(NO₃)₂ salts and N,N′-bis(salicylidene)-1,2-bis-(o-aminophenoxy)ethane (H₂L) in 80% dioxane/water and pure methanol were determined from conductance measurements. The magnitudes of these ion association constants are related to the nature of the solvation of the cation and the complexed cation. The mobilities of the complexes are also dependent, in part, upon solvation effects.