Dendrimer-Like Chiral Stationary Phases Derived from (1R, 2R)-(+)-1,2-Diphenylethylenediamine and 1,3,5-Benzenetricarbonyl Trichloride

Three dendrimers were synthesized directly on aminated silica gel using (1R, 2R)-(+)-1,2-diphenylethylenediamine and 1,3,5-benzenetricarbonyl trichloride as building blocks. The chiral stationary phases were obtained by modification of these dendrimers with phenyl isocyanate. All derivatives prepared on silica gel were characterized by FTIR spectrum, solid-state ¹H NMR and elemental analysis. The enantioseparation ability of the chiral stationary phases was preliminarily evaluated by high-performance liquid chromatography. The chiral stationary phase of one-generation dendrimer exhibited best enantioseparation ability.     

Synthesis and quadratic molecular hyperpolarizabilities of two new chiral boronates: Computational and experimental study

A monomeric boronate and an oxobridged chiral dimer were obtained by reaction of the ligand derived from 4-diethylaminosalicylaldehyde with (R)-(−)-phenylglycinol, and phenyl boronic acid or boric acid. The compounds were fully characterized by spectroscopic techniques (¹H, ¹³C, ¹¹B NMR, elemental analyses, IR and masses spectrometry); and their molecular hyperpolarizabilities were investigated by the electric field induced second harmonic (EFISH) technique and semi-empirical calculations. The experimental quadratic hyperpolarizability which is equal to 9.8 × 10⁻³⁰ cm⁵ esu⁻¹ at 1.064 μm for the monomeric derivative rises to 19.5 × 10⁻³⁰ cm⁵ esu⁻¹ in the dimeric specie.     

The Preparation of a New Kind of Carbosilane Dendrimer with 4‐(Naphthalen‐1‐yl)phenyl Core‐An Application of Suzuki Coupling Reaction

Using the divergent method, carbosilane dendrimers with p‐bromophenyl core were synthesized by using alternating Grignard and hydrosilylation reactions. And then, α‐naphthalenyl was connected to the core by using Suzuki coupling reaction. This gave a new carbosilane dendrimer with a 4‐(naphthalen‐1‐yl)phenyl core. All the products were characterized by IR, ¹H NMR, ¹³C NMR, ²⁹Si NMR, and MS. The study shows that Suzuki Coupling reaction is an effective and powerful core‐functionalization method and a satisfactory result can be achieved through prolonging the reaction time.     

Calix[4]resorcinarene macrocycles

Supramolecular chemistry is an interdisciplinary scientific field, including chemical, physical and biological properties of more complex chemical species than the molecules themselves. Calixarenes/calixresorcinarenes are macrocyclic compounds, consisting of ‘n’ phenolic/resorcinolic units linked together by methylene bridges; these macrocycles are often used for molecular recognition. Thus, different modifications can be made to both the lower and upper rim, allowing the construction of well-defined multivalent buildings. In this work, three calix[4]resorcinarene macrocycles were synthesized, namely C-dec-9-en-1-ylcalix[4]resorcinarene (CAL 11U), C-trans-2, cis-6-octa-1,5-dien-1-ylcalix[4]resorcinarene (CAL 9U) and C-nonylcalix[4]resorcinarene (CAL 10) by a simple condensation reaction. The compounds CAL 11U and CAL 10 have been already synthesized by researchers, while the CAL 9U has been synthesized for the first time. Their structures were confirmed using ATR-FTIR, ¹H NMR and ¹³C NMR. Thermal analysis combined with mass spectrometric evolved analysis of the vapors was used to study the thermal behavior of the different synthesized molecules, and they were the subject of characterization by X-ray powder diffraction in order to analyze their degree of crystallinity.

     

Chiral dioxovanadium(V) complexes with single condensation products of 1,2-diaminocyclohexane and aromatic o-hydroxycarbonyl compounds: Synthesis,characterization, catalytic properties and structure

New dioxovanadium(V) complexes bearing tridentate products of single condensation of RR(−) and of SS(+)-1,2-diaminocyclohexane with salicylaldehyde and its derivatives, 2-hydroxy-1-naphthaldehyde and 1-hydroxy-2-acetonaphthone, have been synthesized. The crystal structure of the {RR(−)-1-amino-2-N-[1′-(1″-oxido-κO-2″-naphthyl)ethylidene]aminocyclohexane-κ²N}dioxovanadium(V) hemihydrate hemiethanol solvate, determined by X-ray analysis, is characterized by trigonal bipyramidal coordination geometry of complex molecules which are linked to solvent molecules by hydrogen bonds to form chains. The cyclohexane ring is in chair conformation with a very small distortion towards half-chair and envelope forms. Complexes were characterized by UV–Vis, FTIR, ¹H, ¹³C, ⁵¹V NMR and CD spectroscopies. CD spectra of {RR(−)-1-amino-2-N-[(2′-oxido-κO-5′-nitrophenyl)methylene]aminocyclohexane-κ²N}dioxovanadium(V) and of R(−)-1,2-diaminopropane analogue do not bear mirror image relationship in contrast to V(IV and V), Cu(II) and Ni(II) complexes containing double condensed diamines in the same absolute configurations. ¹H and ¹³C NMR resonance signals of all complexes dissolved in DMSO were assigned. The complexes bearing the methoxy substituent in position 3 or 5 of the aryl group catalyse the oxidation of methyl phenyl sulfide by cumene hydroperoxide to the corresponding sulfoxide with reasonable enantiomeric excesses (19–23%).     

Synthesis and thermal behavior of Janus dendrimers,part 1

Eight Janus-type dendrimers up to the second generation were synthesized, and their thermal properties were evaluated. Compounds consist of the dendritic bisMPA based polyester moieties, and either 3,4-dihexyloxybenzoic acid or 3,4-dihexadecyloxybenzoic acid moieties, attached to opposite sides of the pentaerythritol core. The structures of the molecules were verified with ¹H NMR, ¹³C NMR, ESI TOF mass spectrometry and elemental analysis. The thermal stability was evaluated by thermogravimetric analysis, displaying onset decomposition temperatures (T_d) ranging from 241 to 308 °C. Phase transitions were studied by differential scanning calorimetry. Based on the performed studies it was confirmed that OH terminated dendrimers 2, 4, 6 and 8 exhibited liquid crystalline phases. Also, the X-ray powder diffraction measurements were accomplished for the dendrimers having terminal hydroxyl groups.     

Cyclophane-based tetra(resorcinarene) as a host for both histone and hydrophobic molecular guests

A cyclophane-based resorcinarene tetramer, which is constructed with a tetraaza[6.1.6.1]paracyclophane and four resorcinarenes bearing hepta(carboxylic acid) residues that connect the macrocycle through amide linkages, was prepared. The binding constant of the cyclophane-based resorcinarene with immobilized histone was determined to be 1.3 × 10⁷ M⁻¹ by surface plasmon resonance measurements, which was 31-fold larger than that of the resorcinarene monomer bearing octacarboxylic acids. Moreover, the cyclophane-based tetra(resorcinarene) acted as a host toward hydrophobic molecular guests such as 6-p-toluidinonaphthalene-2-sulfonate.     

Gallium and indium dithiocarboxylates: Synthesis, spectroscopic characterization and structure of [MeGa(S2Ctol)2]

Several gallium and indium dithiocarboxylate complexes of the type [Me_nM(S₂CR)_3−n] (M = Ga, In; n = 0, 1, 2; R = phenyl (Ph), p-tolyl (tol), mesityl (Mes)) have been synthesized. These complexes were characterized by elemental analysis, IR, UV-vis and NMR (¹H,¹³C{¹H}) spectroscopy. Structure of [MeGa(S₂Ctol)₂] was established by X-ray crystallography. The gallium atom adopts a distorted five coordinate geometry which is intermediate between trigonal bipyramidal and square pyramidal configurations. The complex [Me₂InS₂Ctol] underwent a two-step thermal decomposition leading to the formation of tetragonal β-In₂S₃.     

Synthesis and spectroscopic properties of Schiff bases derived from 3-hydroxy-4-pyridinecarboxaldehyde

A series of six new Schiff bases has been prepared by reacting aniline and 4-R-substituted anilines (R=CH₃, OCH₃, Br, Cl, NO₂) with 3-hydroxy-4-pyridinecarboxaldehyde. The ¹H, ¹³C, ¹⁵N and ¹⁷O NMR data of these compounds are used to discuss the tautomerism. ¹⁵N NMR and ¹⁷O NMR chemical shifts established the tautomer existing in solution as the hydroxy/imino. ¹³C CPMAS NMR confirms that the same tautomer is found in the solid state. The stabilities of the tautomeric forms have been approached using density functional calculations (B3LYP/6-31G**) in the gas phase. In all cases the neutral hydroxy/imino with E configuration is more stable than the oxo/enamino form (by ∼22 kJ mol⁻¹) and significantly more stable than the betaine (by ∼75 kJ mol⁻¹).     

Synthesis and characterization of new soluble fluorinated seco-porphyrazines

Magnesium porphyrazinate substituted with eight 3,5-bis(trifluoromethyl)phenyl groups on the peripheral positions has been synthesized by the cyclotetramerization of 3,4-[3,5-bis(trifluoromethyl)phenyl]pyrroline-2,5-diimine in the presence of magnesium butanolate. Acid-mediated demetallation of the magnesium porphyrazine resulted in peripheral oxidation of one pyrrole ring to reveal the seco-porphyrazine, octakis[3,5-bis(trifluoromethyl)phenyl]-2-seco-porphyrazine-2,3-dione. Further reaction of this product with copper (II) acetate, zinc (II) acetate and cobalt (II) acetate has led to the metallo-derivatives, {octakis[3,5-bis(trifluoromethyl)phenyl]-2-seco-2,3-dioxoporphyrazinato} M(II) [M = Cu(II), Zn(II), Co(II)]. These new soluble complexes were characterized by elemental analysis, together with FT-IR, ¹H NMR, ¹³C NMR, ¹⁹F NMR, UV-Vis and mass spectral data.     

Ultraviolet light absorber with low surface energy: synthesis and characterization

Novel fluorine-containing ultraviolet absorbers (FBPs) with low surface energy were successfully synthesized based on 2,4-dihydroxy benzophenone (BP-1), and their structures were characterized by ¹H NMR, ¹³C NMR, FTIR, and HRMS. UV absorption of FBPs was studied in 10⁻⁴ M dichloromethane (CH₂Cl₂), which demonstrated the superior UV absorption capability of FBPs (ca. ?=1.7×10⁴ to 2.2×10⁴ at λ_max) over the matrix (?=1.7×10⁴ at λ_max). Quantum chemistry calculation was performed to investigate the stable structure and UV electronic absorption bands of FBPs. The surface chemistry information of high-chlorinated polyethylene (HCPE) coating films embedded with ultraviolet absorbers (UVAs) was given by X-ray photoelectron spectroscopy (XPS) and contact angle measurement. The results show that the surface enrichment capability of FBPs is remarkably better than traditional UVAs (including BP-1, BP-3, BP-12) because of the low surface energy properties of FBPs.     

Synthesis and characterization of chiral azobenzene dye functionalized Janus dendrimers

Eight bischromophoric bisMPA based polyester Janus dendrimers emanating from a pentaerythritol core were synthesized and their properties evaluated. 4-((4-(Ethyl(2-(2-(6-methoxynaphthalen-2-yl)propanoyloxy)ethyl)amino)-phenyl)diazenyl)-benzoic acid and 4-((4-(ethyl(2-(2-(6-methoxynaphthalen-2-yl)propanoyloxy)-ethyl)-amino)phenyl)diazenyl)-3-nitrobenzoic acid were attached to the dendritic polyester skeleton to make chiral dendrimers up to the second generation. The structures and the purity of the molecules were verified with ¹H NMR, ¹³C NMR, ESI TOF mass spectrometry, and elemental analysis. Spectral properties were evaluated with UV-vis and CD spectrometer. The compounds displayed broad absorption maxima in the visible region. The CD spectra confirmed the optical purity of the compounds. The thermal properties were evaluated by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC).     

Resorcinarene-dendrimers with stilbene moieties for optoelectronics

Dendrimers with resorcinarene core and π-conjugated dendron branches with 16 and 32 stilbene groups have been synthesized and characterized by ¹H and ¹³C NMR, FTIR, UV–vis, fluorescence spectroscopy, MALDI-TOF, electrospray or FAB⁺ mass spectrometry, and elemental analysis. Homogeneous thin films of resorcinarene-dendrimers deposited on quartz, glass or ITO substrates were prepared by spin-coating. All the materials showed absorption in the UV region in both chloroform solutions and thin films. The band gap energies (E_g) determined from both UV–vis spectroscopy and voltammetry were in the semiconducting range. A slight decrease in the E_g values was observed when passing from the first generation of dendrimers to the second one, which can be attributed to an increase in the π-conjugated system. The fluorescence quantum yield of the molecules in solution was low and practically null in the solid state. Nevertheless, a very interesting behavior was observed in the reductive voltammetric cycle, where electrochromism from transparent to blue forms occurred in the film by n-doping process; property that makes these materials suitable for the development of electrochromic devices such as smart windows.     

A new route to novel 10-deoxoartemisinins

A series of novel 10-deoxoartemisinin derivatives was synthesized with high regioselectivity and yields using Heck reactions from 10β-allyldeoxoartemisinin. The configuration of the double bond of the product was determined from ¹H NMR coupling constants (J_2′-3′).     

Comprehensive characterization of surface-functionalized poly(amidoamine) dendrimers with acetamide,hydroxyl, and carboxyl groups

Terminal amine groups of poly(amidoamine) (PAMAM) dendrimers can be substituted with different functional groups for various applications. In this study, PAMAM derivatives with acetamide, hydroxyl, and carboxyl termini were synthesized from ethylenediamine (EDA) core generation 4 and 5 primary amine-terminated PAMAM dendrimers. The reaction products were purified with dialysis and subsequently characterized by polyacrylamide gel electrophoresis (PAGE), capillary electrophoresis (CE), size exclusion chromatography (SEC), matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry, potentiometric titration, ¹H NMR, and ¹³C NMR. PAGE and CE electropherograms provide data regarding the purity, charge distribution, and electrophoretic mobility of the dendrimers and their derivatives. SEC and MALDI-TOF mass spectrometry detect the average absolute molar mass and the individual mass fractions, respectively. The combination of SEC with potentiometric titration provides quantitative evidence of the degree of the functional group substitution, while NMR techniques (both ¹H NMR and ¹³C NMR) confirmed the changes in dendrimer surface functionalization. This study provides a general example for the comprehensive characterization of surface-functionalized PAMAM dendrimer nanoparticles. The synthesized dendrimer derivatives hold promise for environmental and medical applications.     

Thermoreversible UCST-type phase behavior of comb-like poly(N-phenyl maleimide-co-n-octadecyl vinyl ether) in organic media

Comb-like copolymer of N-phenyl maleimide and n-octadecyl vinyl ether was synthesized by conventional free radical solution polymerization. The molecular weight and molecular weight distribution were measured by GPC. The chemical composition of copolymer was characterized by FT-IR, ¹H NMR and ¹³C NMR, and the results indicated that the obtained copolymer contained much more content of N-phenyl maleimide rather than equal molar ratio of monomer unit. The comb-like copolymer can exhibit upper critical solution temperature thermoresponsive phase behavior reversibly in N,N-dimethylformamide and some proper alcohols such as 1-butanol, 1-hexanol, etc. The effect of polymer concentration and co-solvent on thermoresponsive behavior of polymer solution was investigated, and the cloud point of polymer solution can be tuned conveniently. The high resolution ¹H NMR method was used to comprehend the reversible thermoresponsive behavior in molecular level, and the results revealed that as temperature decreased the pendent long alkyl side chain aggregated and phase separation occurred at cloud point temperature; however, the mobility of main polymer chain decreased at lower temperature.     

The microwave-assisted synthesis and characterization of novel, octakis(2-hydroxyethoxy)resorcinarene bridged polymeric metallophthalocyanines

The new metallophthalocyanine (Zn, Cu, Ni, Co) polymers containing 4,6,10,12,16,18,22,24-octakis(2-hydroxyethoxy)-2,8,14,20-tetramethylresorcinarene are described. Firstly, 4,6,10,12,16,18,22,24-octakis(2-hydroxyethoxy)-2,8,14,20-tetramethylresorcinarene compound (1) was synthesized by treating resorcinarene with 2-chloroethanol under microwave irradiation. Then, tetrakis(4,5-bis(2-hydroxyethoxy))phthalonitrile substituted resorcinarene compound (2) and octakis(4-(2-hydroxyethoxy))phthalonitrile substituted resorcinarene compound (3) were synthesized by treating compound (1) with 4,5-dichloro-1,2-dicyanobenzene and 4-nitro-1,2-dicyanobenzene, respectively, under microwave irradiation. The chlorides Cu (II), Ni (II), Co (II), were employed in order to synthesize the corresponding metallophthalocyanine polymers (2b–d and 3b–d) and Zn(CH₃COO)₂ was used for the preparation of zinc phthalocyanine polymers (2a and 3a). All products were synthesized by microwave-assisted synthesis method. The structures were characterized by elemental analyses, ¹H NMR, ¹³C NMR, UV–Vis and FTIR spectroscopy.     

PEPPSI-Pd-NHC catalyzed Suzuki-Miyaura cross-coupling reactions in aqueous media

A series of unsymmetrical 1,3-disubstituted benzimidazolium chlorides were synthesized as N-heterocyclic carbene (NHC) precursors. These compounds were used to synthesize of the PEPPSI-type palladium NHC complexes. The structures of all compounds were characterized by ¹H NMR, ¹³C NMR, FT-IR spectroscopy and elemental analyses. The catalytic activity of the PEPPSI-type palladium–NHC complexes has been evaluated with respect to the Suzuki-Miyaura cross-coupling reactions of phenyl boronic acid with various aryl halides in aqueous media.     

Synthesis and characterization of dendrons and dendrimers skeleton-constructed with azobenzene moiety

A series of dendrons and dendrimers skeleton-constructed with azobenzene moiety based upon 4-carboxy-4′-(1,2-propanediolether)-azobenzene as an AB₂ monomer, via a convergent approach, proceeding in a repeated stepwise growth manner starting from 4-carboxy-4′-(n-butylether)-azobenzene as a peripheral monomer, were synthesized, and characterized by NMR, FTIR, and MALDI-TOF-MS analysis. Their regular molecular architecture and thus monodispersed molecular weights were confirmed by GPC. The UV-Vis absorbance and ¹H NMR spectrum study indicated that the azobenzene moieties in CHCl₃ solution took fully trans-cis isomerization under UV irradiation, and reversely isomerization back to the trans by visible light irradiation or by heat.     

Complete assignment of NMR data of 22 phenyl‐1H‐pyrazoles' derivatives

Complete assignment of ¹H and ¹³C NMR chemical shifts and J(¹H/¹H and ¹H/¹⁹F) coupling constants for 22 1‐phenyl‐1H‐pyrazoles' derivates were performed using the concerted application of ¹H 1D and ¹H, ¹³C 2D gs‐HSQC and gs‐HMBC experiments. All 1‐phenyl‐1H‐pyrazoles' derivatives were synthesized as described by Finar and co‐workers. The formylated 1‐phenyl‐1H‐pyrazoles' derivatives were performed under Duff's conditions. Copyright © 2011 John Wiley & Sons, Ltd.