- Structures and properties of coordination polymers with a rigid zwitterionic pyridinium-based tricarboxylate ligand
-
Four coordination polymers of different transition metal ions with a new zwitterionic tricarboxylate ligand, 1-(3,5-dicarboxylatophenyl)-4-carboxylatopyridinium (L2?) were synthesized, and characterized. They are formulated as [Cu3L
- Yang, Xiao,Sui, Qi,Gong, Teng,Gao, En-Qing
-
-
Read Online
- Generalizable synthesis of bioresponsive near-infrared fluorescent probes: Sulfonated heptamethine cyanine prototype for imaging cell hypoxia
-
Continued advancement in bioresponsive fluorescence imaging requires new classes of activatable fluorescent probes that emit near-infrared fluorescence with wavelengths above 740 nm. Heptamethine cyanine dyes (Cy7) have suitable fluorescence properties bu
- Atkinson, Kirk M.,Morsby, Janeala J.,Kommidi, Sai Shradha Reddy,Smith, Bradley D.
-
supporting information
p. 4100 - 4106
(2021/05/19)
-
- Novel asymmetric viologen compound as well as preparation method and application thereof (by machine translation)
-
The invention discloses a novel asymmetric viologen compound and a preparation method and application thereof, wherein the novel asymmetric viologen compound is mainly composed of 4, 4' - bipyridine and different electron donating groups, electron withdra
- -
-
Paragraph 0052-0053; 0056
(2020/10/30)
-
- From Chelating to Bridging Ligands: N-Sulfonyliminoimidazolium Ylides as Precursors to Anionic N-Heterocyclic Carbene Ligands
-
The synthesis and investigation of a new family of anionic N-heterocyclic carbene (NHC) ligands, based on N-sulfonyliminoimidazolium ylides, is reported. Their corresponding silver complexes have been synthesized and present distinctive geometries compare
- Guérin, Vincent,Ménard, Alain,Guernon, Hannah,Moutounet, Odile,Legault, Claude Y.
-
p. 409 - 416
(2019/01/14)
-
- Approach to a Substituted Heptamethine Cyanine Chain by the Ring Opening of Zincke Salts
-
Cyanine dyes play an indispensable and central role in modern fluorescence-based biological techniques. Despite their importance and widespread use, the current synthesis methods of heptamethine chain modification are restricted to coupling reactions and nucleophilic substitution at the meso position in the chain. Herein, we report the direct transformation of Zincke salts to cyanine dyes under mild conditions, accompanied by the incorporation of a substituted pyridine residue into the heptamethine scaffold. This work represents the first general approach that allows the introduction of diverse substituents and different substitution patterns at the C3′-C5′ positions of the chain. High yields, functional tolerance, versatility toward the condensation partners, and scalability make this method a powerful tool for accessing a new generation of cyanine derivatives.
- ?tacková, Lenka,?tacko, Peter,Klán, Petr
-
supporting information
p. 7155 - 7162
(2019/05/10)
-
- Cobalt-Catalyzed Trifluoromethoxylation of Epoxides
-
A catalytic ring-opening reaction of epoxides by nucleophilic trifluoromethoxylation of trifluoromethyl arylsulfonate has been developed based on the use of a cobalt catalyst. This reaction provides an efficient, simple route for directly construction of a wide range of vicinal trifluoromethoxyhydrins under mild conditions. In addition, this method can convert terminal epoxides into target products with good chemo- and regioselectivity.
- Liu, Jie,Wei, Yongliang,Tang, Pingping
-
supporting information
p. 15194 - 15199
(2018/11/30)
-
- Nucleophilic Substitution Reactions of 2,4-Dinitrophenyl X-Substituted-Benzenesulfonates and Y-Substituted-Phenyl 4-Nitrobenzenesulfonates with Azide Ion: Regioselectivity and Reaction Mechanism
-
The second-order rate constants for reactions of 2,4-dinitrophenyl X-substituted-benzenesulfonates (4a-4f) and Y-substituted-phenyl-4-nitrobenzenesulfonates (5a-5f) with N3- ion have been measured spectrophotometrically. The reactions of 4a-4f proceed through S-O and C-O bond fission pathways competitively. Fraction of the S-O bond fission decreases rapidly as the substituent X in the benzenesulfonyl moiety changes from an electron-withdrawing group to an electron-donating group. The Hammett plots for reactions of 4a-4f are linear with ρX=1.87 and 0.56 for the S-O and C-O bond fission, respectively. The fact that the substituent X is further away from the reaction site of the C-O bond fission than that of the S-O bond fission is one reason for the smaller ρX value. The nature of the reaction mechanism (i.e., a stepwise mechanism in which expulsion of the leaving group occurs after the rate-determining step) is also responsible for the smaller ρX value obtained from the C-O bond fission. The Bronsted-type plot for the reactions of 5a-5f is linear with βlg=-0.63, which is typical for reactions reported previously to proceed through a concerted mechanism. Effects of substituents X and Y on regioselectivity and reaction mechanism are discussed in detail.
- Moon, Ji-Hyun,Kim, Min-Young,Han, So-Yeop,Um, Ik-Hwan
-
p. 1360 - 1365
(2015/07/15)
-
- Kinetic study on alkaline hydrolysis of Y-substituted phenyl X-substituted benzenesulfonates: Effects of changing nucleophile from azide to hydroxide ion on reactivity and transition-state structure
-
Second-order rate constants (kOH-) for alkaline hydrolysis of 2,4-dinitrophenyl X-substituted benzenesulfonates (1a-1f) and Y-substituted phenyl 4-nitrobezenesulfonates (2a-2g) have been measured spectrophotometrically. Comparison of kOH/
- Moon, Ji-Hyun,Kim, Min-Young,Han, So-Yeop,Um, Ik-Hwan
-
p. 1563 - 1568
(2015/08/11)
-
- A kinetic study on nucleophilic displacement reactions of aryl benzenesulfonates with potassium ethoxide: Role of K+ ion and reaction mechanism deduced from analyses of LFERs and activation parameters
-
Pseudofirst-order rate constants (kobsd) have been measured spectrophotometrically for the nucleophilic substitution reactions of 2,4-dinitrophenyl X-substituted benzenesulfonates 4a-f and Y-substituted phenyl benzenesulfonates 5a-k with EtOK in anhydrous ethanol. Dissection of k obsd into kEtO- and kEtOK (i.e., the second-order rate constants for the reactions with the dissociated EtO - and ion-paired EtOK, respectively) shows that the ion-paired EtOK is more reactive than the dissociated EtO-, indicating that K + ion catalyzes the reaction. The catalytic effect exerted by K + ion (e.g., the kEtOK/kEtO- ratio) decreases linearly as the substituent X in the benzenesulfonyl moiety changes from an electron-donating group (EDG) to an electron-withdrawing group (EWG), but it is independent of the electronic nature of the substituent Y in the leaving group. The reactions have been concluded to proceed through a concerted mechanism from analyses of the kinetic data through linear free energy relationships (e.g., the Bronsted-type, Hammett, and Yukawa-Tsuno plots). K+ ion catalyzes the reactions by increasing the electrophilicity of the reaction center through a cyclic transition state (TS) rather than by increasing the nucleofugality of the leaving group. Activation parameters (e.g., ΔH? and ΔS?) determined from the reactions performed at five different temperatures further support the proposed mechanism and TS structures.
- Um, Ik-Hwan,Kang, Ji-Sun,Shin, Young-Hee,Buncel, Erwin
-
p. 490 - 497
(2013/03/13)
-
- Variation of the viologen electron relay in cyclodextrin-based self-assembled systems for photoinduced hydrogen evolution from water
-
The light-driven reduction of protons for the production of molecular hydrogen in multicomponent systems depends on electron relays such as viologens. We describe here the effect of viologens appended with guest moieties (adamantane or bile acid) on the e
- Contreras Carballada, Pablo,Mourtzis, Nikos,Felici, Marco,Bonnet, Sylvestre,Nolte, Roeland J. M.,Williams, Rene M.,De Cola, Luisa,Feiters, Martin C.
-
p. 6729 - 6736
(2013/01/15)
-
- Cs2CO3 catalyzed rapid and efficient conversion of amines into sulfonamides; Alcohols and phenols into sulfonic esters
-
A simple and efficient method has been developed for the sulfonylation of several amines, alcohols, and phenols by p-toluenesulphonylchloride (p-TsCl) in the presence of catalytic amount of Cs2CO3 at 25C to obtain sulfonamides and sulfonic esters in very good yields. Cs2CO3 has been found to be highly efficient catalyst. Taylor & Francis Group, LLC.
- Reddy, M. B. Madhusudana,Pasha
-
experimental part
p. 1867 - 1875
(2011/10/11)
-
- Method of screening compounds
-
The present invention is directed to a novel, target-blind approach to drug discovery. The concept is to model human phenotypes in a teleost, such as a zebrafish, and then screen compounds, e.g., small molecules, for their ability to alter the phenotype.
- -
-
-
- Regioselectivity and the nature of the reaction mechanism in nucleophilic substitution reactions of 2,4-dinitrophenyl X-substituted benzenesulfonates with primary amines
-
Second-order rate constants have been measured for the reaction of 2,4-dinitrophenyl X-substituted benzenesulfonates with a series of primary amines. The nucleophilic substitution reaction proceeds through competitive S-O and C-O bond fission pathways. The S-O bond fission occurs dominantly for reactions with highly basic amines or with substrates having a strong electron-withdrawing group in the sulfonyl moiety. On the other hand, the C-O bond fission occurs considerably for the reactions with low basic amines or with substrates having a strong electron-donating group in the sulfonyl moiety, emphasizing that the regioselectivity is governed by both the amine basicity and the electronic effect of the sulfonyl substituent X. The apparent second-order rate constants for the S-O bond fission have resulted in a nonlinear Bronsted-type plot for the reaction of 2,4-dinitrophenyl benzenesulfonate with 10 different primary amines, suggesting that a change in the rate-determining step occurs upon changing the amine basicity. The microscopic rate constants (k1 and k2/k-1 ratio) associated with the S-O bond fission pathway support the proposed mechanism. The second-order rate constants for the S-O bond fission result in good linear Yukawa-Tsuno plots for the aminolyses of 2,4-dinitrophenyl X-substituted benzenesulfonates. However, the second-order rate constants for the C-O bond fission show no correlation with the electronic nature of the sulfonyl substituent X, indicating that the C-O bond fission proceeds through an SNAR mechanism in which the leaving group departure occurs rapidly after the rate-determining step.
- Um, Ik-Hwan,Hong, Jin-Young,Kim, Jung-Joo,Chae, Ok-Mi,Bae, Sun-Kun
-
p. 5180 - 5185
(2007/10/03)
-
- Ammonolysis of Aryl Toluenesulphonate Esters: Evidence for the Concerted Displacement of the Aryl Oxide Group
-
Rate constants have been measured for the ammonolysis of aryl toluenesulphonate esters in aqueous solution.The Broensted-type β value of -1.08 coupled with the βeq for the overall reaction indicates a large increase in negative effective charge
- Suttle, Nicola A.,Williams, Andrew
-
p. 1563 - 1568
(2007/10/02)
-