Catalytic enantioselective desymmetrization of meso-glutaric anhydrides using a stable Ni2-Schiff base catalyst

We describe the desymmetrization of meso-glutaric anhydrides to chiral hemiesters using a bench-stable homodinuclear Ni(2)-(Schiff base) complex as the catalyst in good to excellent yield (up to 99%) and enantioselectivity (up to 94%). Using the opposite enantiomer of the catalyst, we obtained the same yield and enantioselectivity with the opposite configuration, thereby gaining access to both hemiester enantiomers.     

Application of paramagnetic NMR-validated molecular dynamics simulation to the analysis of a conformational ensemble of a branched oligosaccharide

Oligosaccharides of biological importance often exhibit branched covalent structures and dynamic conformational multiplicities. Here we report the application of a method that we developed, which combined molecular dynamics (MD) simulations and lanthanide-assisted paramagnetic NMR spectroscopy, to evaluate the dynamic conformational ensemble of a branched oligosaccharide. A lanthanide-chelating tag was attached to the reducing end of the branched tetrasaccharide of GM2 ganglioside to observe pseudocontact shifts as the source of long distance information for validating the conformational ensemble derived from MD simulations. By inspecting the results, the conformational space of the GM2 tetrasaccharide was compared with that of its nonbranched derivative, the GM3 trisaccharide.     

Whose deletion does not affect your payoff? The difference between the Shapley value, the egalitarian value, the solidarity value, and the Banzhaf value

This study provides a unified axiomatic characterization method of one-point solutions for cooperative games with transferable utilities. Any one-point solution that satisfies efficiency, the balanced cycle contributions property (BCC), and the axioms related to invariance under a player deletion is characterized as a corollary of our general result. BCC is a weaker requirement than the well-known balanced contributions property. Any one-point solution that is both symmetric and linear satisfies BCC. The invariance axioms necessitate that the deletion of a specific player from games does not affect the other players’ payoffs, and this deletion is different with respect to solutions. As corollaries of the above characterization result, we are able to characterize the well-known one-point solutions, the Shapley, egalitarian, and solidarity values, in a unified manner. We also studied characterizations of an inefficient one-point solution, the Banzhaf value that is a well-known alternative to the Shapley value.     

Ferromagnetic coupling promoted by kappa3N:kappa2N bridging system

Syntheses, structures, and magnetic properties of novel trinuclear complexes of the same motif [M{Cu(pz2bg)2}M]4+ (M = CuII, NiII, CoII, MnII), catena-[Cu2{Cu(pz2bg)2}(Hpz)2(PhSO3)2](PhSO3)2.4H2O (2.4H2O), [Ni2{Cu(pz2bg)2}(MeOH)2(H2O)4](NO3)4 (3), [Co2{Cu(pz2bg)2}(NO3)2(EtOH)2](NO3)2 (4), and [Mn2{Cu(pz2bg)2}(NO3)4(MeCN)2] (5), which include the complex ligand [Cu(pz2bg)2] (1), are reported (Hpz = pyrazole, pz2bg- = di(pyrazolecarbimido)aminate; bispyrazolyl derivative of biguanidate). The reaction of Cu(ClO4)2.6H2O, sodium dicyanamide, Hpz, and PhSO3H.H2O (1:2:4:4) in MeOH yielded blue crystals of [Cu2(1)(Hpz)2(PhSO3)2](PhSO3)2.4H2O (2.4H2O). In 2, the tricopper(II) units, which consist of two Cu(II) ions bridged by 1, are linked by benzenesulfonate anions to form a ladder structure. Complex 1 was isolated by removing the terminal Cu(II) ions from 2 with use of Na(4)edta. Complexes 3-5 were obtained by the reaction of 1 with an excess of each M(II) ion. In 2-5, the adjoining metal ions are ferromagnetically coupled via the pz2bg- ligand with J values of +7.2(1), +7.5(1), +2.7(1), and +0.3(1) cm(-1), respectively, using a spin Hamiltonian H = -2J(S(M1)S(Cu) + S(Cu)S(M2)). The ferromagnetic interaction was attributed to the strict orthogonality of magnetic dsigma orbitals, which are controlled by the kappa3N:kappa2N bridging geometry of the pz2bg- ligands.     

The first crystal structure of an alkaline metal salt of thioglucose: potassium 1‐thio‐β‐D‐glucoside monohydrate

In the crystal structure of the title hydrated salt, poly[(μ₂‐aqua)(μ₄‐1‐sulfido‐β‐D‐glucoside)potassium], [K(C₆H₁₁O₅S)(H₂O)]_n or K⁺·C₆H₁₁O₅S⁻·H₂O, each thioglucoside anion coordinates to four K⁺ cations through three of its four hydroxy groups, forming a three‐dimensional polymeric structure. The negatively charged thiolate group in each anion does not form an efficient coordination bond with a K⁺ cation, but forms intermolecular hydrogen bonds with four hydroxy groups, which appears to sustain the polymeric structure. The Cremer–Pople parameters for the thioglucoside ligand (Q = 0.575, θ = 8.233° and ϕ = 353.773°) indicate a slight distortion of the pyranose ring.     

A facile method for generation of carbon oxide sulfide

Carbon oxide sulfide was easily generated upon heating of amine salts of carbamothioic acids at 85°C which were produced in situ from amines, carbon monoxide, and elemental sulfur in the presence of a catalytic amount of selenium under mild conditions.