Ground and excited-state electronic interactions in poly(propylene amine) dendrimers functionalized with naphthyl units: effect of protonation and metal complexation.

We report the absorption spectra and the photophysical properties (fluorescence spectrum, quantum yield, and lifetime) of four dendrimers of the poly(propylene amine) family (POPAMs) functionalized at the periphery with naphthylsulfonamide (hereafter called naphthyl) units. Each dendrimer Gn, where n = 1 to 4 is the generation number, comprises 2n + 1 (i.e., 32 for G4) naphthyl functions in the periphery and 2n + 1--2 (i.e., 30 for G4) tertiary amine units in the branches. All the experiments have been carried out in acetonitrile solutions. Comparison with two reference compounds (N-methyl-naphthalene-2-sulfonamide, A, and N-(3-dimethylamino-propyl)-2-naphthalene-1-sulfonamide, B) has shown that the absorption spectra of the dendrimers are significantly different from those expected from the component units. Furthermore, the intense fluorescence band of the naphthyl unit (lambda max = 343 nm; phi = 0.15, tau = 8.5 ns) is strongly quenched in the dendrimers. The quenching effect increases with increasing generation and is accompanied by the appearance of a weak and broad emission tail at lower energy. Protonation of the amine units of the dendrimers by addition of CF3SO3H (triflic) acid causes a strong increase in the intensity of the naphthyl luminescence and a change in the form of the emission tail. The shapes of the titration curves depend on dendrimer generation, but in any case, the effect of the acid can be fully reversed by successive addition of a base (tributylamine). The results obtained show that in the dendrimers there are interactions (both in the ground and excited states) between naphthyl units as well as between naphthyl units and amine units of the branches; this gives rise to dimer/excimer and charge-transfer/exciplex excited states. Titration with Zn(CF3SO3)2 has the same effect as acid titration, as far as the final emission spectrum is concerned, but a much higher concentration of Zn(CF3SO3)2 has to be used and the shapes of the titration plots are very different. Titration with Co(NO3)2.6H2O causes a much smaller increase in the intensity of the naphthyl fluorescence compared with Zn(CF3SO3)2. The results obtained have shown that protonation and metal coordination can reveal the presence of ground and excited state electronic interactions in functionalized poly(propylene amine) dendrimers, and that the presence of photo-active units in the dendrimers can be useful to reveal some peculiar aspects of the protonation and metal coordination processes.     

手性樟脑磺酰胺的合成及应用

Chiral sulfonamides derived from( d)-10-camphorsulfonyl chloride and chiral amines were prepared and used in the copper-catalyzed conjugate addition of organometallic reagents to enones. The chiral sulfonamides/CuCN catalysts provided high catalytic activity and moderate enantioselectivity in the conjugate addition of diethylzinc to 2-cyclohexenone and 2-cyclohepteneone, but low enantioselectivity to the 2-cyclopentenone and acyclic enones.     

Study of the Chemical Space of Selected Bacteriostatic Sulfonamides from an Information Theory Point of View

The relative structural location of a selected group of 27 sulfonamide‐like molecules in a chemical space defined by three information theory quantities (Shannon entropy, Fisher information, and disequilibrium) is discussed. This group is composed of 15 active bacteriostatic molecules, 11 theoretically designed ones, and para‐aminobenzoic acid. This endeavor allows molecules that share common chemical properties through the molecular backbone, but with significant differences in the identity of the chemical substituents, which might result in bacteriostatic activity, to be structurally classified and characterized. This is performed by quantifying the structural changes on the electron density distribution due to different functional groups and number of electrons. The macroscopic molecular features are described by means of the entropy‐like notions of spatial electronic delocalization, order, and uniformity. Hence, an information theory three‐dimensional space (IT‐3D) emerges that allows molecules with common properties to be gathered. This space witnesses the biological activity of the sulfonamides. Some structural aspects and information theory properties can be associated, as a result of the IT‐3D chemical space, with the bacteriostatic activity of these molecules. Most interesting is that the active bacteriostatic molecules are more similar to para‐aminobenzoic acid than to the theoretically designed analogues.     

Non-empirical calculations of NMR indirect spin-spin coupling constants. Part 13: configurational assignment of aminosulfonylamidines

Carbon-carbon coupling constants have been experimentally measured using the INADEQUATE pulse sequence in the series of N-[1,2-bis(dialkylamino)-2-arylethylidene]arylsulfonamides obtained from N-(1-aryl-2,2,2-trichloroethyl)amides of arylsulfonic acids. Comparison of the experimental J(C,C) in this series with those calculated at the SOPPA (Second-Order Polarization Propagator Approach) level in the model aminosulfonylamidine provided an unambiguous assignment at the C=N bond of the eight-title aminosulfonylamidines to E-configuration, while the unknown J(C,C) couplings in their inaccessible diverse Z isomers have been predicted with high reliability. The established marked difference between J(C,C) of the corresponding carbon-carbon bonds in cis and trans orientations to the nitrogen lone pair in aminosulfonylamidines provides a powerful tool in the configurational assignment at the C=N bond in a wide series of the related systems containing the C=N-SO2R moiety.     

Trace quantification of selected sulfonamides in aqueous media by implementation of a new dispersive solid‐phase extraction method using a nanomagnetic titanium dioxide graphene‐based sorbent and HPLC‐UV

Herein, a new dispersive solid‐phase extraction method using a nano magnetic titanium dioxide graphene‐based sorbent in conjunction with high‐performance liquid chromatography and ultraviolet detection was successfully developed. The method was proved to be simple, sensitive, and highly efficient for the trace quantification of sulfacetamide, sulfathiazole, sulfamethoxazole, and sulfadiazine in relatively large volume of aqueous media. Initially, the nano magnetic titanium dioxide graphene‐based sorbent was successfully synthesized and subsequently characterized by scanning electron microscopy and X‐ray diffraction. Then, the sorbent was used for the sorption and extraction of the selected sulfonamides mainly through π–π stacking hydrophobic interactions. Under the established conditions, the calibration curves were linear over the concentration range of 1–200 μg/L. The limit of quantification (precision of 20%, and accuracy of 80–120%) for the detection of each sulfonamide by the proposed method was 1.0 μg/L. To test the extraction efficiency, the method was applied to various fortified real water samples. The average relative recoveries obtained from the fortified samples varied between 90 and 108% with the relative standard deviations of 5.3–10.7%.     

Synthesis and structure of para‐toluene sulfonamide lanthanide complexes and their application in the polymerization of ε‐caprolactone

A series of para‐toluene sulfonamide ligands [TsNHPr‐i( HL ₁ ), TsNHBu‐t( HL ₂ ), TsNHPh( HL ₃ ), TsNHPhMe‐p( HL ₄ ), TsNHPhOMe‐p( HL ₅ )] were synthesized by amidation using para‐toluene sulfonyl chloride reacting with different primary amines. A series of homoleptic lanthanide complexes (Ln L₃, 1–10) (Ln = La, L = L₁ ( 1 ), Ln = Gd, L = L₂ ( 2 ), Ln = La, L = L₂ ( 3 ), Ln = Gd, L = L₂( 4 ), Ln = La, L = L₃ ( 5 ), Ln = Gd, L = L₃ ( 6 ), Ln = La, L = L₄ ( 7 ), Ln = Gd, L = L₄( 8 ), Ln = La, L = L₅ ( 9 ), Ln = Gd, L = L₅ ( 10 )) were prepared by amine elimination reactions of the ligands with Ln[N(SiMe₃)₂]₃ (Ln = La, Gd). Complexes 1 , 3 , 5 , 7 and 9 were all characterized by NMR spectra, and the structures of complex 3 was determined by single‐crystal X‐ray diffraction. Complex 3 crystallizes a binuclear cluster, consisting of two La³⁺ and six (TsNBu‐t)⁻ anions. Three (TsNBu‐t)⁻ anions are chelating to each La³⁺ as bidentate model with O and N forming three‐membered chelate rings; one of three anions is bridging to another La³⁺ via oxygen. All complexes were characterized using elemental analysis and infrared spectra. The catalytic properties of complexes 1–10 for the ring‐opening polymerization of ε‐caprolactone were studied and the results showed that all complexes are efficient initiators for this ring‐opening polymerization reaction.     

Synthesis,characterization and catalytic properties of novel palladium(II) complexes containing aromatic sulfonamides: effective catalysts for the oxidation of benzyl alcohol

In this article, N‐(2‐aminophenyl)arylsulfonamides (1–5) were successfully synthesized by the reaction of o‐phenylenediamine and various benzenesulfonyl chlorides. The Schiff base derivatives (1a–f; 4e) of those compounds were obtained using different aldehydes. Then, a series of neutral‐four coordinate Pd(II) complexes (6–10) were prepared from the reaction of Pd(OAc)₂ and 1–5. On the other hand, when we tried to synthesize Pd(II) complexes containing Schiff base/sulfonamide ligands, two different situations were observed. Generally, when an electron‐donating group was attached to the imine fragment (1a–d) except for 1f, the Schiff base hydrolyzed and 6 was isolated. When an electron‐withdrawing group was attached to the imine fragment (1e, 4e), neutral four‐coordinate Pd(II) complexes (11–13) bearing Schiff base/sulfonamide ligands were isolated. The synthesized compounds were characterized by FT‐IR, elemental analysis and NMR spectroscopy. The complexes were used as a catalyst in the oxidation reaction of benzyl alcohol to benzaldehyde in the presence of H₅IO₆ in acetonitrile. All complexes showed satisfactory catalytic activity. The highest catalytic activity was obtained with 9. Copyright © 2012 John Wiley & Sons, Ltd.     

Hollow fiber liquid‐phase microextraction and determination of nonsteroidal anti‐inflammatories by capillary electrophoresis and sulfonamides by HPLC in human urine

In this paper two applications of three‐phase HF‐LPME for the determination of pharmaceuticals in human urine are proposed: a capillary electrophoresis with a photodiode array detection method for the analysis of seven nonsteroidal anti‐inflammatory drugs (NSAIDs) and a high‐performance liquid chromatographic with photo diode array and fluorescence detection method for the determination of four sulfonamides and their corresponding N⁴‐acetyl‐metabolites. Q3/2 Accurel® polypropylene hollow fibers were used for both procedures. Dihexyl ether was used as the supported liquid membrane for the determination of anti‐inflammatories and 1‐octanol for sulfonamides. An aqueous solution (pH 12) was used in both procedures as the acceptor phase and as the donor phase an aqueous solution (pH 2), and a 2 m Na₂SO₄ aqueous solution (pH 4) was used for the determination of the anti‐inflammatories and sulfonamides. The detection limits obtained were between 0.25 (naproxen) and 0.86 ng/mL (aceclofenac) for the determination of anti‐inflammatories and 7 × 10^?4 (sulfamethoxazole) and 0.048 ng/mL (N⁴‐acetyl‐sulfamethazine) for sulfonamides. The method was successfully applied to the determination of the analytes in human urine. Copyright © 2012 John Wiley & Sons, Ltd.     

Controlled ring‐opening polymerization of lactide by bis‐sulfonamide/amine associations: Cooperative hydrogen‐bonding catalysis

The bis‐sulfonamide m‐C₆H₄(SO₂NHPh)₂ efficiently promotes the ring‐opening polymerization of lactide when combined with tertiary amines, such as N,N‐dimethylaminopyridine. Polylactides of controlled molecular weights (M_n up to 17,700 g mol^?1) and very narrow molecular weight distributions (M_w/M_n < 1.11) are obtained under mild conditions and in a living fashion. The reaction takes place through a bifunctional mechanism involving activation of both the alcohol and the monomer. Modulation of the sulfonamide component supports cooperative dual hydrogen‐bonding of lactide involving the two (SO₂NHAr) moieties. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 959–965, 2010