Synthesis and chiroptical properties of helical polyallenylferrocenes

The allylnickel‐catalyzed living coordination polymerization of allenylferrocene was compounded, two allenylferrocene derivatives (L‐1 and D‐1) bearing chiral amide pendants were designed and synthesized. The living coordination polymerization of L‐1 and D‐1 were afforded by the allynickel(II) complexes, which gave the polymer with controlled molecular weights and narrow molecular weight distribution in high yields. Three polyallenylferrocenes exhibited electrochemical properties. The helical structure was stable in the aprotic solvents observed through the circular dichroism spectra. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 2663–2669     

Synthesis of a new urea derivative: a dual-functional organocatalyst for Knoevenagel condensation in water

A phenylalanine–urea compound-catalyzed Knoevenagel condensation in water is reported. Various aldehydes and active methylene compounds undergo condensation at room temperature to give the desired products in high yields. The mechanism of the condensation of aldehydes with Meldrum’s acid catalyzed by the novel urea derivative is also disclosed.     

Synthesis and chiroptical properties of helical polyallenes bearing chiral cholesteryl pendant groups

A cholesteryloxyallene (1) bearing chiral cholesteryl pendant group was designed and synthesized. Living polymerization of this monomer with an allylnickel complex as a catalyst give poly(cholesteryloxyallene)s (poly‐ 1 _ms) in high yields with controllable molecular weights and narrow molecular weight distributions. These polymers were found to possess a dynamic helical conformation with a preferred handedness in n‐hexane as confirmed by circular dichroism and absorption spectra as well as optical ratios. The helical conformation of the polymers was revealed to stabilize as the number of repeat units increased until the degree of polymerization reached 100. The helical conformation of poly‐ 1 ₁₀₀ could be controlled by altering the temperature of solutions. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 2227–2233     

Synthesis,structure, and properties of a coordination polymer based on N- and O-donors

A ternary coordination polymer, [Cd(L)(pbda)_0.5] _n [HL?=?3,5-bis(2-pyridylmethyl)aminobenzoic acid, pbda?=?dianion of 1,4-benzenedicarboxylic acid], has been synthesized and characterized by elemental analysis, FT-IR spectroscopy, powder X-ray diffraction, thermogravimetric analysis, and single-crystal X-ray diffraction analysis. The single-crystal X-ray crystallography reveals that the complex is a 2-D wave-like network. The cadmium has an unsymmetrical seven-coordinate [CdN₂O₅] geometry, coordinated by two nitrogens and five oxygens from L^? and pbda. Hydrogen bonds between the uncoordinated (2-pyridylmethyl)amino groups from adjacent layers form dimers across the inversion center, superposing different layers to construct a 3-D framework. To the best of our knowledge, [Cd(L)(pbda)_0.5] _n represents the first example of a complex containing 3,5-bis(2-pyridylmethyl)aminobenzoate.     

Synthesis, chiroptical properties and photoinduced birefringence of optically active methacrylic copolymers bearing side-chain bisazoaromatic moieties

Three series of optically active photochromic copolymers, deriving from methyl methacrylate (MMA) and the chiral bisazoaromatic monomers (S)-3-methacryloyloxy-1-[4′-phenylazo-(4-azobenzene)]-pyrrolidine [(S)-MPAAP], (S)-3-methacryloyloxy-1-[4′-cyanophenylazo-(4-azobenzene)]-pyrrolidine [(S)-MPAAP-C] and (S)-3-methacryloyloxy-1-[4′-nitrophenylazo-(4-azobenzene)]-pyrrolidine [(S)-MPAAP-N], have been prepared and characterized in solution and in the solid state with the aim to evaluate the effect on their chiroptical and thermal properties originated by the insertion of inactive MMA groups along the main chain. The optical activity displayed by the bisazo polymers is discussed in terms of extent of chiral conformation assumed by the macromolecules as a consequence of dipole-dipole interactions between the bisazoaromatic chromophores.The photoinduction of birefringence has been assessed on thin films of the investigated copolymers in order to evaluate their behaviour as materials for optical data storage. The results are interpreted in terms of copolymer composition and conformational stiffness of the bisazoaromatic chromophoric co-units, which are responsible for the optical response rates, and are compared to those of the similar derivatives containing only one azo bond. The observed enhanced thermal properties and the temporal stability appear of interest for a potential use of these materials in nano technologies for all-optical data manipulation and in optoelectronics.     

Synthesis,structure and properties of a one-dimensional coordination polymer containing both dicyanamide and ethylenediamine

The nickel(II) complex [Ni(en)₂{N(CN)₂}]ClO₄ 1 (en?=?ethylenediamine) has been synthesized and its structure determined. The complex forms a one-dimensional chain structure via the bidentate bridging ligand dicyanamide. A two-dimensional network is formed via interchain hydrogen-bond interactions. The magnetic properties of the compound (5–300?K) show the existence of weak antiferromagnetic exchange interactions between paramagnetic centers along chains.     

Synthesis, structure and the binding properties of the amide-based anion receptors derived from 1H-indole-7-amine

Indole-7-amine was investigated as an alternative to aniline in construction of amide-based anion receptors. Replacement of aniline with indolamine introduces additional binding site—indolyl NH, which can enhance anion binding for more than five times. The molecular modelling of indole-containing receptors revealed the correlation between their conformational preferences and their affinity towards anions.     

First-principle calculations of the electronic properties of poly(p-phenylenevinylene), polyacetylene, and their derivatives

Results of density-functional studies of the electronic properties of poly(p-phenylene-vinylene) (PPV) and polybutadiene are presented. The calculations were performed using a single-chain, full-potential, linearized muffin-tin orbital (LMTO)-based method. In particular, we analyze the effects on the electronic properties due to the addition of substituents to the vinylene linkage. As substituents, we concentrate on cyano and amine groups. It is found that these groups induce large changes in the band structures of these systems, particularly of the bands closest to the Fermi level. Further, the effects on the band gap and on the total energy due to the bond-length alternation of the polymer backbones, are analyzed both for unsubstituted and substituted polybutadiene. It is found that both properties depend sensitively on both the substituents attached to the chain and on the precise structure of the polymer. The substituents lead to overall redistributions of the electrons and, in particular, the disubstituted PPV is found to have a large dipole moment perpendicular to the polymer axis. For disubstituted polybutadiene we find a stronger C–C bond-length alternation than for the unsubstituted compound (polyacetylene), and the results for this compound indicate that the band gap of substituted and unsubstituted PPV depends strongly on the bond-length alternation.     

Synthesis and characterization of a new disubstituted polyacetylene containing indolylazo moieties in side chains

A new disubstituted polyacetylene with indolylazo moieties in its side chains ( 9 ) was synthesized by a post functionalization strategy, which was difficult, or perhaps impossible, to obtain from the direct polymerization of its corresponding monomer. The polymer is soluble in common solvents and thermally stable. The polymer shows good optical transparency with an absorption maximum at 393 nm and a band edge at ～530 nm. Its poled film exhibits a resonant d₃₃ value of 17.9 pm/V and its optical nonlinearity is resistant to thermal decay at up to 147 °C. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 5672–5681, 2006     

Synthesis,Conformation, and Metabolism of a Selenium Bilirubin

Summary. A symmetrical C(10)-selena-bilirubin analog, 8,12-bis(2-carboxyethyl)-7,13-dimethyl-2,3,17,18-tetraethyl-10-selenabiladiene-ac-1,19(21H,24H)-dione was synthesized from 8-(2-carboxyethyl)-2,3-diethyl-7-methyl-(10H)-dipyrrin-1-one in one step by reaction with diselenyl dichloride. The selena-rubin exhibited UV-vis and NMR spectroscopic properties similar to those of the parent mesobilirubin, and like bilirubin and mesobilirubin, it adopts an intramolecularly hydrogen-bonded conformation, shaped like a ridge-tile but with a steeper pitch. The longer C–Se bond lengths (2.2Å) and smaller bond angles at C–Se–C (88°), as compared to C–CH₂–C (1.5Å, 106°), lead to an interplanar angle between the two dipyrrinones of only 72°, which is considerably less than that of bilirubin (100°) and close to that (74°) of its 10-thia-rubin analog. Despite the conformational distortion, the sensitivity of Se toward oxidation and the typically weak C–Se bond, the selena-rubin is metabolized in normal rats, like bilirubin, to acyl glucuronides, which are secreted into bile. In mutant (Gunn) rats lacking bilirubin glucuronosyl transferase (UGT1A1), glucuronide or other metabolites of the selena-rubin were not detected in bile, demonstrating the importance of hepatic glucuronidation for its biliary excretion.     

Synthesis and chiroptical properties of optically active poly(N‐propargylamide) bearing photoisomerizable azobenzene moieties

A chiral azobenzene‐containing N‐propargylamide monomer, that is, (R)‐2‐(4‐phenylazophenoxy)‐n‐prop‐2‐ynyl‐propionamide, was prepared and polymerized in the presence of a rhodium catalyst to yield an optically active polyacetylene. The ¹H NMR analysis of the polymer indicated a predominant cis structure of the backbone (cis concentration = 80%); and the chiroptical property studies showed an enhanced optical rotatory power and a strong Cotton effect, indicating the formation of a secondary helical conformation. A reversible optical modulation of chiroptical properties of the polymer due to the reversible photoisomerization of the azobenzene was observed. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 6047–6054, 2006     

含咔唑和偶氮苯的乙炔衍生物的合成

采用Sonagashira偶联反应和N-烷基化反应合成了含有咔唑和偶氮苯的乙炔衍生物:3-乙炔基-9-(4-[4-(硝基)苯基偶氮苯]氧)亚丁基咔唑3.其结构通过IR,1H NMR,13C NMR,元素分析和X-射线单晶衍射法测定.标题化合物属单斜晶系,P21/c空间群;a=9.238(3),b=28.240(8),c...     

Synthesis,crystal structures and magnetic properties of three Ni(II) complexes having NiN4 core with argentocyanide,terephthalate and dicyanamide ions: From discrete molecule to a helical network

This work describes the synthesis and X-ray crystallographic characterization of three nickel(II) complexes [Ni(3,2,3-tet){Ag(CN)₂}₂] (1), [Ni(3,2,3-tet)(μ-tp)]_n · 1.5nH₂O (2) and {[Ni(3,2,3-tet)(μ_1,5-dca)](ClO₄)}_n (3) where 3,2,3-tet = N,N′-bis(3-aminopropyl)-1,2-ethylenediamine, tp = terephthalate and dca = dicyanamide. Compound 1 is a heterotrinuclear discrete distorted octahedral molecule whereas compound 2 forms a 1D polymeric network and an extended 2D network is formed by intermolecular hydrogen bonding. Interestingly, two adjacent 1D chains execute a novel double-helical network constructed by Ni(II) and the bridging dca ligand in compound 3. The variable temperature magnetic susceptibility measurements for compounds 2 and 3 were also carried out.     

Synthesis and chiroptical properties of a new type of chiral depsipeptide dendrons

A new type of chiral depsipeptide dendrons based on tartaric acid as branching juncture and ω-aminocapronic acid as spacer has been prepared. Natural and unnatural tartaric acid building blocks have been incorporated, providing access to combinatorial libraries. All compounds have been completely characterized by FAB-MS, EA analysis, ¹H/¹³C NMR- and UV/Vis-spectroscopy. ¹H NMR relaxation measurements have been used to examine the conformational flexibility of these dendrons in CH₃CN and CH₃OH and indicate a less flexible structure in CH₃CN. Pulse gradient spin echo (PGSE) NMR measurements correlate these findings to molecular dimensions. A reduced size for the dendrons in CH₃CN compared to CH₃OH leads to the assumption of a more compact structure in this solvent. Additional polarimetric data reveal, that observed changes in optical activity with increasing generation can in CH₃OH be explained by constitutional effects of the dendron structure but not in CH₃CN. CD measurements are in agreement with these findings and show a linear increase of the Cotton effects with increasing generation for CH₃OH but not for CH₃CN. It can be concluded that the conformation within the dendrons is very sensitive to environmental conditions and that a chiral secondary structure might be stabilized in CH₃CN. Initial studies revealed that chirality transfer to the focal functionality occurs.     

Anion nucleophilicity in ionic liquids: a comparison with traditional molecular solvents of different polarity

The nucleophilic reactivity of a homogeneous series of anions (halides, pseudohalides and organic anions) in the ionic liquids [hexmim] [ClO₄] and [hexmim] [PF₆] has been measured in their reaction with n-alkyl methanesulfonates, and compared with that found in traditional molecular solvents of different polarity, that is, chlorobenzene, DMSO, and MeOH.     

Cu(II) complex of a flexible tripodal receptor as a highly selective fluorescent probe for iodide

A Cu(II) complex of a tripodal receptor bearing an anthracene moiety on one pod as a fluorophore was synthesized. The anion recognition behavior of the Cu(II) complex was evaluated in CH₃CN/H₂O (95:5, v/v), resulting in an extremely high selectivity for iodide over other anions such as F⁻, Cl⁻, Br⁻, , CH₃COO⁻, and . The Cu(II) complex acts as a selective probe for estimating iodide even in the presence of other anions without any interference.     

Synthesis, characterization and photocrosslinking properties of polyacrylamides having bromo substituted pendant cinnamoyl moieties

New 3- and 4-bromocinnamoyl aniline were synthesized condensing 4-aminoacetophenone and the respective bromobenzaldehydes in the presence of sodium hydroxide. The monomers, 4-(3′-bromocinnamoyl) phenyl acrylamide (4,3′-BCPA) and 4-(4′-bromocinnamoyl) phenyl acrylamide (4,4′-BCPA) were prepared by reacting the respective chalcones and acryloyl chloride in the presence of triethylamine at 0-5 °C. Homopolymers of 4,3′-BCPA and 4,4′-BCPA was carried out in methyl ethyl ketone using benzoyl peroxide (BPO) under nitrogen atmosphere at 70 °C. The prepared polymers were characterized by UV, IR, ¹H-NMR and ¹³C-NMR techniques. The molecular weights (M_w and M_n) of the polymers were determined by gel permeation chromatography. The thermogravimetric analysis (TGA) of the polymers in nitrogen atmosphere reveals that they possess very good thermal stability required of a negative type photoresist. The glass transition temperature of poly(4,3′-BCPA) and poly (4,4′-BCPA) were found to be 55 and 64 °C respectively. The solubility of the polymers was tested in various polar and non-polar solvents. Photocrosslinking nature of the polymer samples was carried out in the presence and absence of various triplet photosensitizers in solution phase using chloroform solvent under medium frequency UV light. For using the polymers as negative photoresist materials the rate of photocrosslinking of the polymers was measured under the influence of different solvents, concentrations and position of the substituent.