- Thermodynamic N-donor trans influence in labile pseudo-octahedral zinc complexes: A delusion?
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While the forces responsible for the chelate effect are well-established in coordination chemistry, the origin and implementation of the related thermodynamic trans influence remains debatable. This work illustrates a simple approach for quantifying this effect in labile pseudo-octahedral [Zn(Lk)3]2+ complexes lacking stereochemical preferences (Lk = L1-L4 are unsymmetrical didentate α,α′-diimine ligands). In line with statistics, the triply degenerated meridional isomers mer-[Zn(Lk)3]2+ are stabilized by 0.8 ≥ ΔGexch mer→fac ≥ 4.2 kJ/mol over their nondegenerated facial analogues fac-[Zn(Lk)3]2+ and therefore display no apparent trans influence at room temperature. However, the dissection of the free energy terms into opposite enthalpic (favoring the facial isomers) and entropic (favoring the meridional isomers) contributions reveals a trans influence assigned to solvation processes occurring in polar solvents. Altogether, the thermodynamic trans influence operating in [Zn(α,α′-diimine)3]2+ complexes is 1-2 orders of magnitude smaller than the chelate effect. A weak templating effect provided by a noncovalent lanthanide tripod is thus large enough to produce the wanted facial isomer at room temperature.
- Aboshyan-Sorgho, Lilit,Lathion, Timothe,Gune, Laure,Besnard, Cline,Piguet, Claude
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- Design, synthesis and biological activity evaluation of a new class of 2,4-thiazolidinedione compounds as insulin enhancers
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Diabetes mellitus (DM) is a global disease with a high incidence of type 2 diabetes. Current studies have shown that insulin enhancers play an important role in the treatment of type 2 diabetes and have great importance in the improvement of type 2 diabetes. In this research, Rosiglitazone was taken as the lead compound, and the structure was modified by using the bioisostere principle, and a new class of 2,4-thiazolanedione compound was designed and synthesised. The novel series of compounds were studied for their biological activities in vitro and in vivo. In vitro tests, the biological activities showed that the target compounds have good selective activation of peroxisome-proliferator-activated receptor γ (PPARγ), such as the compounds 6a, 6e, 6f, 6g and 6i, especially the compound 6e to PPARγ was EC50 = 0.03 ± 0.01 μmol/L in vitro. Then, in vivo biological activities’ test results showed that the tendency of increasing in blood sugar had an obvious inhibiting effect, and had a significant insulin hypoglycaemic effect of enhancing and extending the exogenous. In addition, the results of cytotoxicity tests and acute toxicity tests (LD50) showed that these compounds belong to the low toxicity compounds.
- Huiying, Zou,Guangying, Chen,Shiyang, Zhou
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- NOVEL NUCLEOSIDE OR NUCLEOTIDE DERIVATIVES, AND USES THEREOF
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The present disclosure relates to a novel nucleoside or nucleotide derivative, a racemate thereof, a stereoisomer thereof, or a pharmaceutically acceptable salt thereof; and a pharmaceutical composition for preventing or treating viral infection-associated diseases, containing the same as an active ingredient.
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Paragraph 0059; 0087
(2020/12/10)
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- BACE1 INHIBITORS
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The present invention provides a compound of formula I, having BACE1 inhibitory activity, their manufacture, pharmaceutical compositions containing them and their use as therapeutically active substances. The active compounds of the present invention are useful in the therapeutic and/or prophylactic treatment of e.g. Alzheimer's disease.
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Page/Page column 71
(2017/03/08)
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- Smaller than a nanoparticle with the design of discrete polynuclear molecular complexes displaying near-infrared to visible upconversion
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This work shows that the operation of near-infrared to visible light-upconversion in a discrete molecule is not limited to non-linear optical processes, but may result from superexcitation processes using linear optics. The design of nine-coordinate metallic sites made up of neutral N-heterocyclic donor atoms in kinetically inert dinuclear [GaEr(L1)3]6+ and trinuclear [GaErGa(L2)3]9+ helicates leads to [ErN9] chromophores displaying unprecedented dual visible nanosecond Er(4S3/2→4I15/2) and near-infrared microsecond Er(4I13/2→4I15/2) emissive components. Attempts to induce one ion excited-state absorption (ESA) upconversion upon near-infrared excitation of these complexes failed because of the too-faint Er-centred absorption cross sections. The replacement of the trivalent gallium cation with a photophysically-tailored pseudo-octahedral [CrN6] chromophore working as a sensitizer for trivalent erbium in [CrEr(L1)3]6+ improves the near-infrared excitation efficiency, leading to the observation of a weak energy transfer upconversion (ETU). The connection of a second sensitizer in [CrErCr(L2)3]9+ generates a novel mechanism for upconversion, in which the superexcitation process is based on the CrIII-sensitizers. Two successive Cr→Er energy transfer processes (concerted-ETU) compete with a standard Er-centred ETU, and a gain in upconverted luminescence by a factor larger than statistical values is predicted and observed.
- Zare, Davood,Suffren, Yan,Gune, Laure,Eliseeva, Svetlana V.,Nozary, Homayoun,Aboshyan-Sorgho, Lilit,Petoud, Stphane,Hauser, Andreas,Piguet, Claude
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p. 2529 - 2540
(2015/02/19)
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- Ruthenium(II) as a novel labile partner in thermodynamic self-assembly of heterobimetallic d-f triple-stranded helicates
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Unsymmetrical substituted bidentate benzimidazol-2-ylpyridine ligands L2 and L3 react with [Ru(dm-so)4Cl2] in ethanol to give statistical 1:3 mixtures of fac-[Ru(Li)3]2+ mer-[Ru(Li)3]2+ (i=2, 3; ΔGθ isomerisation= -2.7 kJ mol-1). In more polar solvents (acetonitrile, methanol), the free energy of the facial?meridional isomerisation process favours mer-[Ru(Li)3]2+, which is the only isomer observed in solution at the equilibrium (ΔGθ isomerisation≤-11.4 kJ mol-1). Since the latter process takes several days for [Ru(L2)3]2+, fac-[Ru(L2) 3]2+ and mer-[Ru(L2)3]2+ have been separated by chromatography, but the 28-fold increase in velocity observed for [Ru (L3)3]2+ provides only mer-[Ru(L3)3] (ClO4)2 after chromatography (RuC60H 51N9O8Cl2, monoclinic, P2 1/n, Z=4). The facial isomer can be stabilised when an appended tridentate binding unit, connected at the 5-position of the benzimidazol-2- ylpyridine unit in ligand L1, interacts with nine-coordinate lanthanides (III). The free energy of the facial?meridional isomerisation is reversed (ΔGθisomerisation≥ 11.4 kJ mol-1), and the Ru-N bonds are labile enough to allow the quantitative thermodynamic self-assembly of HHH-[RuLu(L1)3]5+ within hours ([RuLu(L1)3](CF3SO3)4.5Cl 0.5(CH3OH)2.5: RuLuC106H 109Cl0.5N21O19S4.5F 13.5, triclinic, P1, Z=2). Electrochemical and photophysical studies show that the benzimidazol-2-ylpyridine units in L1-L3 display similar π-acceptor properties to, but stronger π-donor properties than, those found in 2,2′-bipyridine. This shifts the intraligand π→π * and the MLCT transitions toward lower energies in the pseudo-octahedral [Ru(Li)3]2+ (i=2, 3) chromophores. The concomitant short lifetime of the 3MLCT excited state points to efficient, thermally activated quenching via low-energy Ru-centred d-d states, a limitation which is partially overcome by mechanical coupling in HHH-[RuLu(L1)3] 5+.
- Torelli, Stephane,Delahaye, Sandra,Hauser, Andreas,Bernardinelli, Gerald,Piguet, Claude
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p. 3503 - 3516
(2007/10/03)
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- A comparison of the lability of mononuclear octahedral and dinuclear riple-helical complexes of cobalt(II)
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The lability of the mononuclear octahedral complex tris(5-methyl-2-(1'-methylbenzimidazol-2-yl)-pyridine)cobalt(II), [Co(2)3]2+, is compared with the dinuclear triple-helical complex tris[bis[1-methyl-2-(5'-methylpyrid-2'yl]benzimida
- Charbonnière, Lo?c J.,Williams, Alan F.,Frey, Urban,Merbach, André E.,Kamalaprija, Philippe,Schaad, Olivier
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p. 2488 - 2496
(2007/10/03)
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- Syntheses of Segmental Heteroleptic Ligands for the Self-Assembly of Heteronuclear Helical Supramolecular Complexes
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The development of a modified Phillips reaction allows the synthesis of complicated heteroleptic ligands based on pyridine and 1H-benzimidazole moieties.The key-step formation of aromatic 1H-benzimidazole rings from N-(2-nitroaryl)arenecarboxamides significantly improves the possibilities of the classical intermolecular Phillips reactions and can be applied to the synthesis of large oligo-multidentate units.Segmental heteroleptic ligands containing two different bidentate coordinating units (see 14) or bidentate and terdentate sites connected by 'diphenylmethane' (= methylenebis(phenylene)) spacers (see 15 and 16) were obtained in fair to good yield by using multistep syntheses following this strategy.Heterotrileptic ligands (bidentate-terdentate-bidentate, see 19 and 20; terdentate-terdentate-terdentate, see 23) requiring the simultaneous formation of four 1H-benzimidazole rings in one step were prepared and demonstrate the extended possibilities of this methodology.Data are presented to show that the milder conditions used for this modified Phillips reaction together with its flexibility are essential for the development of ligands adapted for the self-assembly of heteronuclear helical complexes.
- Piguet, Claude,Bocquet, Bernard,Hopfgartner, Gerard
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p. 931 - 942
(2007/10/02)
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- Pyridinecarboxylic acid amide derivatives and pharmaceutical compositions comprising same
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Compounds are disclosed of the formula STR1 wherein R1 is hydrogen, C1 -C3 alkyl or diphenylmethyl; Y is --NH(CH2)n --R2 ; R2 is OH or --ONO2 ; m is 2 or 3; and n is 9
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- Antiallergic agents. III. N-(1H-tetrazol-5-yl)-2-pyridinecarboxamides
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A series of N-tetrazolylpyridinecarboxamides was prepared and evaluated for antiallergic activity by the passive cutaneous anaphylaxis assay. From the structure-activity relationships of this class of compounds, it was revealed that the N-tetrazolylcarbamoyl group as an acidic functionality is required to be at the 2-position of the pyridine nucleus and that the phenyl group as a substituent is not necessarily required for activity. 6-Methyl-N-(1H-tetrazol-5-yl)-2-pyridinecarboxamide showed good oral activity and low toxicity.
- Honma,Hanamoto,Hashiyama,et al.
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p. 125 - 128
(2007/10/02)
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