Synthesis of a gold(I) complex with a (thio)phosphine-modified β-cyclodextrin

A gold(I) complex with the bidentate ligand 6^A-S-[2-(diphenylphosphino)-ethyl]thio-β-cyclodextrin has been prepared. The complex has been studied by mass spectrometry as well as IR and NMR spectroscopy. The influence of the ligand:metal ratio on the coordination mode has also been examined.     

The asymmetric hydration of 1-octene to (S)-(+)-2-octanol with a biopolymer–metal complex,silica-supported chitosan–cobalt complex

A new biopolymer-non-noble metal catalyst, silica-supported chitosan–cobalt complex (SiO₂–CS–Co), has been prepared by a simple method and found to be a high stereoselective catalyst for asymmetric hydration of 1-octene to (S)-(+)-2-octanol amounted to 97.8%ee when fitting conditions were selected. This catalyst was very stable and could be reused several times without any remarkable change in catalytic activity and optical selectivity. Obviously, the present work has provided a more economical alternative way for the preparation of a chiral 2-octanol.     

Synthesis,structure and norbornene polymerization activity of a bulky β-diketiminato palladium(II) complex

A new bulky β-diketiminato palladium(II) complex was synthesized by direct reaction of (ⁱPr₂Ph)₂nacnacH ((ⁱPr₂Ph)₂nacnac = CH{C(Me)N(C₆H₃-2,6-ⁱPr₂)}₂) with Pd(OAc)₂ which yielded [(ⁱPr₂Ph)₂nacnac]Pd(OAc) as a mononuclear species with chelating nacnac and acetato ligands. Preliminary investigations into the polymerization of norbornene in the presence of BF₃OEt₂ were performed.     

Synthesis of (S)-α-amino oleic acid

An efficient synthesis of (S)-α-amino oleic acid was developed. The fully protected FA derivative was obtained in four steps starting from methyl (2S)-2-[bis(tert-butoxycar-bonyl)amino]-5-oxopentanoate. These steps are (i) olefination of the starting aldehyde with the appropriate phosphonate anion, (ii) hydrogenation of the double bonds, (iii) controlled reduction of ω-ethyl ester to an aldehyde in the presence of α-methyl ester, and (iv) a Wittig reaction of the latter aldehyde with the suitable ylide. Free α-amino oleic acid was prepared after deprotection of the amino group followed by saponification in a total yield of 24%. N-tert-Butoxycarbonyl-protected amino oleic acid and the corresponding amino alcohol were prepared in high yield. The structures of the products have been established by various spectroscopic techniques.     

The synthesis of a homochiral methacrylate macromonomer by polymerisation of (R)- or (S)-methyl β-hydroxyisobutyrate

Summary Polymerisations of either enantiomer of commercially available methyl -hydroxyisobutyrates 1a and 1b were carried out. Ti(OBuⁿ)₄ catalysed transesterification of the neat monomer generated either polymer 3 at lower temperatures (100°C) or homochiral macromonomer 2 at higher temperatures. Under optimal conditions for the preparation of the macromonomer 2, a soluble material (Mn 3600, Mw 7000) was produced which displayed high crystallinity as judged by X-ray powder diffraction analysis.     

Structural evidence for a complex participation in the alternating copolymerization of citraconic (α-methylmaleic) anhydride with styrene in N,N-dimethylformamide

Summary The ¹³C DEPT NMR spectra of semi-alternating copolymers of citraconic (α-methylmaleic) anhydride (CA) and styrene (ST) prepared in a very polar solvent, N,N-dimethyformamide (DMF), with AIBN show that more than 50 % of the linkage configuration at the cyclic CA units is in cis configuration. Since the cis linkage configuration may result when the electron donor-acceptor complex formed between the comonomers is involved in the propagation, it is considered that, in very polar DMF, a participation of the complex is the driving force for the copolymerization. Received: 16 November 1998/Accepted: 29 January 1999     

群多普利中间体(2β,3aβ,7aα)-八氢吲哚-2-羧酸的合成

以1,1,3,3-四甲氧基丙烷为原料,经选择性水解、硝基甲烷缩合、脱水、Diels-Adler加成、加压氢化、水解并环合、腈基水解7步反应,得到用于合成心血管药物群多普利的关键中间体(2β,3aβ,7aα)-八氢吲哚-2-羧酸。产物及中间体经1HNMR及MS确证。此反应路线工艺相对简单,成本较低,经优化后,总收率为10.1%。     

β-phase formation in a crosslinkable poly(9,9-dihexylfluorene)

The synthesis of a crosslinkable poly(9,9-dihexylfluorene) derivative is reported. Vinyl ether moieties allow for photolithographic patterning, resulting in an immiscible polyfluorene network, which enables subsequent wet thin-film processing. The metastable β-phase morphology, inherent to most polyfluorene homopolymers, can be induced in this crosslinkable polymer. This is verified by optical spectroscopy, X-ray diffraction and by thermal analysis. The β-phase in polyfluorenes is of interest due to its superior optical and electrical characteristics compared to the amorphous phase. Here, amplified stimulated emission is studied. Surprisingly, the β-phase polymer exhibits higher emission thresholds than the amorphous analogue.     

Synthesis of polymer having β,β-triketone unit in the main chain and its copper (II) complex

Summary A novel polymer having β,β-triketone unit in the main chain was prepared by polycondensation of triethylene glycol bis(p-butoxycarbonylphenyl) ether (1) with triethylene glycol bis(p-acetylacetophenyl) ether (4). The obtained polymer was soluble in CHCl₃, DMF, and DMSO. The structure of the polymer was confirmed by ¹H-NMR. Insoluble brownish yellow copper (II) chelate was obtained by adding a methanol solution of copper (II) acetate to a chloroform solution of the polymer. The IR analysis and the measurement of copper content by iodometric titration showed the quantitative formation of binuclear copper (II) complex. Received: 20 March 1998/Accepted: 17 April 1998     

Pyrazine-bridged dinuclear complex formation by early lanthanides (LaIII,PrIII, NdIII and SmIII) containing bulky fluorinated β-diketonates

The reaction of 1 equivalent of pyrazine (pyz) with two equivalents of Ln(fod)₃ units led to isolation of first example of pyrazine-bridged dinuclear lanthanide β-diketonate complexes of the form [Ln(fod)₃(μ-pyz)Ln(fod)₃] (where fod is the anion of 6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedione and Ln = La, Pr, Nd and Sm). Amazingly only early lanthanides form pyrazine-bridged dinuclear Ln(fod)₃ complexes, although the entire series was explored. The high yield, elemental analysis and NMR of the isolated complexes strongly support their dinuclear nature. The solution structure of the complexes was investigated by ¹H NMR and 4f–4f absorption spectroscopy which confirm their dinuclear nature. The luminescence of Sm–Sm complex, in solution, has been investigated and discussed.     

Synthesis and characterization of optically active helical poly(α, β-unsaturated ketone) with bulky pendant of binaphthyl

The synthesis and chiroptical properties of a novel optically active helical polymers, poly[(S)-6-acryloyl-2,2′-bisalkoxy-1,1′-binaphthyl] (poly-3), were reported. All the monomers readily underwent anionic polymerization to yield the polymers displaying optical rotations and Cotton effects in the UV–vis absorption region of side groups distinct to monomers (3) and the corresponding model compounds such as (S)-6-propionyl-2,2′-bisalkoxy-1,1′-binaphthyl (4) and (S)-6-heptanoyl-2,2′-bisalkoxy-1,1′-binaphthyl (5), implying the formation of main-chain chirality, most probable helicity. Their helical conformations were quite stable as revealed by the almost unchanged chiroptical properties measured at different temperatures.     

合成α,β-不饱和缩酮(醛)的研究

以对甲苯磺酸为催化剂,通过苄叉丙酮与-1,2-丙二醇反应合成了苄叉丙酮-1,2-丙二醇缩酮。较系统的研究了反应溶剂、酮醇物质的量比、催化剂用量等诸因素对产品收率的影响,在n(酮)∶n(醇)=1∶3,催化剂用量为6.5 g/mol(酮),甲苯为带水剂的条件下反应一段时间,再额外加入催化量对甲苯磺酸与少量醇,继续反应,产品收率达到98%。此条件对于其他的α,β-不饱和酮(醛)缩合反应亦适宜。     

β-Fur-2-yl-α-halogenacrylonitrile. V [1] Darstellung von β-(5-Nitro-fur-2-yl)-α-azidoacrylonitril und β-(5-Nitro-fur-2-yl)-α-aminoacrylonitril

β-Fur-2-yl-α-halogenacrylonitriles. V. Preparation of β-(5-Nitro-fur-2-yl)-α-azidoacrylonitrile and β-(5-Nitro-fur-2-yl)-α-aminoacrylonitrile β-(5-Nitro-fur-2-yl)-α-chloroacrylonitrile ( 1 ) reacts with sodium azide to yield β-(5-nitro-fur-2-yl)-α-azidoacrylonitrile ( 2 ). By Staudinger-reaction β-(5-nitro-fur-2-yl)-α-aminoacrylonitrile ( 5 ) is formed. The ¹H- and ¹³C-n.m.r. spectra of E/Z isomers are discussed.     

Insertion of heme b into the structure of the Cys34-carbamidomethylated human lipocalin α(1)-microglobulin: formation of a [(heme)(2) (α(1)-Microglobulin)](3) complex

α(1)-Microglobulin (α(1)m) is a 26 kDa plasma and tissue protein belonging to the lipocalin protein family. Previous investigations indicate that the protein interacts with heme and suggest that it has a function in heme metabolism. However, detailed characterizations of the α(1)m-heme interactions are lacking. Here, we report for the first time the preparation and analysis of a stable α(1)m-heme complex upon carbamidomethylation of the reactive Cys34 by using recombinantly expressed human α(1)m. Analytical size-exclusion chromatography coupled with a diode-array absorbance spectrophotometry demonstrates that at first an α(1)m-heme monomer is formed. Subsequently, a second heme triggers oligomerization that leads to trimerization. The resulting (α(1)m[heme](2))(3) complex was characterized by resonance Raman and EPR spectroscopy, which support the presence of two ferrihemes, thus indicating an unusual spin-state admixed ground state with S=(3)/(2), (5)/(2).     

Synthesis,crystal structure and luminescent properties of new tris-β-diketonate Eu(III) complex with thiadiazolophenanthroline derivative ligand

Herein we describe the synthesis, characterization and spectroscopic properties of the complex tris-(thenoyltrifluoroacetonate)([1, 2, 5]thiadiazolo[3, 4-f][1,10]phenanthroline) europium(III) acetonitrile solvate, [Eu(TTA)₃ TDPHEN] 1.5CH₃CN, where TTA = 2-thenoyl trifluoroacetone and TDPHEN = [1, 2, 5]thiadiazolo[3, 4-f][1, 10] phenanthroline. X-ray crystallography reveals that it is an eight-coordinate Eu(III) complex containing three β-diketonate chelates and one N,N′-bidentate ligand, [1, 2, 5] thiadiazolo[3, 4-f][1, 10] phenanthroline. The excitation at 340 nm of the europium complex in a solution of acetonitrile, and at room-temperature, showed the typical Eu(III) red emission as a sharp band at 611 nm, characteristic of Eu(III) due to the transition ⁵D₀ → ⁷F₂. This complex also showed red emission in the solid state phase (λ_em = 612 nm).     

Thermo- and pH-Responsive Polymersomes of Poly(α,β-N-substituted-DL-aspartamide)s

Materials that can respond to multiple stimuli, such as temperature and pH changes, are of considerable interest for applications in drug delivery systems. Notably, α,β-[poly(2-hydroxyethyl)-DL -aspartamide] is a potentially useful material for such applications. This study investigated the temperature and pH responsiveness of polymers structurally similar to α,β-[poly(2-hydroxyethyl)-DL -aspartamide], namely, poly(α,β-N-substituted-DL -aspartamide)s, in aqueous media. These polymers were derived from polysuccinimide (PSI), which was first synthesized via acid-catalyzed bulk polycondensation of L -aspartic acid (L-ASP) in the presence of 85% o-phosphoric acid under N2. Two primary amino alcohols, 4-aminobutanol (4AB) and 6-aminohexanol (6AH), were then respectively utilized to modify PSI to form poly (α,β-N-substituted-DL -aspartamide)s via aminolysis. Different ratios of these two amino alcohols were used to modify the polymer to produce a series of copolymers with lower critical solution temperatures ranging from 53–28°C when dispersed in aqueous media. Moreover, the properties of the poly(α,β-N- substituted-DL -aspartamide)s in aqueous solution were affected by pH changes. The morphology of the particles formed by these amphiphilic polymers was observed using scanning electronic microscopy and transmission electronic microscopy, and the particles were found to be polymersomes with shell and hollow core structures and diameters of 0.5–1 μm. Other properties of this series of self-assembly copolymers were also characterized. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Some lanthanide (III) complexes of (S,S)-(+)-2,3-dimethoxyl-N,N′-dimethyl-1,4-diaminobutane

Four new optically active complexes of the composition LnL₃Cl₃ (where, L=(S,S)-(+)-2,3-dimethoxyl-N,N^′-dimethyl-1,4-diaminobutane, Ln=La³⁺, Sm³⁺, Pr³⁺ and Nd³⁺) were prepared and characterized on the basis of their chemical analyses, molar conductance, magnetic properties, CD, XPS, visible and IR spectra. It is found that the complexes behave as non-electrolytes in DMSO and in methanol solution and possess the stoichiometric ratio of Ln:C:N:O:Cl =1.1:24.0:6.1:6.0:3.1 which is consistent with the analyses data. The magnetic moments of the complexes show little deviation from the Van Vleck values, indicating that 4f electrons do not participate in bond formation in these chelates. The thermal analysis revealed that all the complexes are anhydrous. Their dominant conformers were determined from CD spectra. A nine-coordinated model was proposed for these complexes.