Complex formation between cationic beta-1,3-glucan and hetero-sequence oligodeoxynucleotide and its delivery into macrophage-like cells to induce cytokine secretion

A cationic polysaccharide bearing a beta-1,3-glucan main-chain structure (CUR-N(+)) forms a complex with a hetero-sequence oligonucleotide, that is, a CpG ODN, and facilitates the transportation of the resultant complex into a murine macrophage-like cell J774.A1, which induces an efficient secretion of a cytokine (IL-12) as compared with that induced by conventional carriers such as poly(ethyleneimine) (PEI) and poly(L-lysine) (PLL).     

Cerium complexes of cyclodextrin dimers as efficient catalysts for luminol chemiluminescence reactions

The chemiluminescence of a luminol-H(2)O(2) system is found to be remarkably enhanced by the Ce(IV) complexes of EDTA-bridged cyclodextrin dimers. The dimers were proved to work much more efficiently than the corresponding monomer. The cavity shape of cyclodextrin moieties and their cooperation displayed an important role in amplifying the chemiluminescence. Further modification of either the cyclodextrin rims or the EDTA linker altered significantly the catalytic abilities of the cyclodextrin dimers, and the examination of the effect of substituents on the chemiluminescence outputs suggested that the proximity between the cyclodextrin cavity and the metallic center might account for the amelioration of the chemiluminescence output.     

Palladium-catalysed regioselective addition reaction of ethyl phenylphosphinate with terminal acetylenes: ligand- and solvent-dependent regioselectivity

Palladium-1,2-bis(diphenylphosphino)ethane complex catalyses regioselective Markovnikov addition of ethyl phenylphosphinate to terminal alkynes in toluene, while the use of tri-tert-butylphosphine as the ligand or ethanol as the solvent leads to regioselectivity reversal.     

Square-planar N2S2NiII complexes with an extended pi-conjugated system

The reaction of a mixture of 2-(1-naphthyl)benzothiazoline (HL1) and 2,6-diphenylbenzo[1,2-d:4,5-d']bisthiazoline (H3L2) with nickel(II) acetate tetrahydrate yielded three kinds of square-planar nickel(II) complexes: one nickel(II) complex with innocent ligands ([Ni(L1)2] (1c)) and two nickel(II) complexes with non-innocent ligands ([Ni(L1-L1)] (1a) and [Ni(L1-L2)] (1b)). The complex 1c has two bidentate-N,S ligands, which are formed via ring opening of HL1. On the other hand, the two complexes 1a and 1b contain a tetradentate-N2S2 ligand, which is created via ring opening of HL1 and H3L2, followed by bond formation between imino carbon atoms. Complexes 1a and 1b show very intense absorptions in the near-infrared (NIR) region, characteristic of square-planar complexes with non-innocent ligands. The third nickel(II) complex having a non-innocent tetradentate-N2S2 ligand ([Ni(L2-L2)] (2)) was prepared from H3L2 and nickel(II) acetate tetrahydrate. The electronic spectrum of 2 exhibits a very intense absorption at 981 nm (epsilon = 3.6 x 10(4) M-1 cm-1), which is significantly red-shifted compared with those of 1a (837 nm and 4.4 x 10(4) M-1 cm-1) and 1b (885 nm and 4.5 x 10(4) M-1 cm-1), indicating the presence of an extended pi delocalization. The reaction of 2,6-bis(3,5-dichlorophenyl)benzo[1,2-d:4,5-d']bisthiazoline (H3L3) with nickel(II) acetate tetrahydrate also led to the formation of a nickel(II) complex with a non-innocent ligand ([Ni(L3-L3)] (3)). While complex 3 is analogous to 2, its electrical conductivity is much higher than that of 2. The molecular structures of 1b, 1c, 2, and 3 were determined by X-ray crystallography.     

Linear metal-metal-bonded tetranuclear M-Mo-Mo-M complexes (M = Ir and Rh): oxidative metal-metal bond formation in a tetrametallic system and 1,4-addition reaction of alkyl halides

Reaction of Mo2(pyphos)4 (1) with [MCl(CO)2]2 (M = Ir and Rh) afforded linear tetranuclear complexes of a formula Mo2M2(CO)2(Cl)2(pyphos)4 (2, M = Ir; 3, M = Rh). X-ray diffraction studies confirmed that two "MCl(CO)" fragments are introduced into both axial sites of the Mo2 core in 1 and coordinated by two PPh2 groups in a trans fashion, thereby forming a square-planar geometry around each M(I) metal. Treatment of 2 and 3 with an excess amount of tBuNC and XylNC induced dissociation of the carbonyl and chloride ligands to yield the corresponding dicationic complexes [Mo2M2(pyphos)4(tBuNC)4](Cl)2 (5a, M = Ir; 6a, M = Rh) and [Mo2M2(pyphos)4(XylNC)4](Cl)2 (7, M = Ir; 8, M = Rh). Their molecular structures were characterized by spectroscopic data as well as X-ray diffraction studies of BPh4 derivatives [Mo2M2(pyphos)4(tBuNC)4](BPh4)2 (5b, M = Ir; 6c, M = Rh), which confirmed that there is no direct sigma-bonding interaction between the M(I) atom and the Mo2 core. The M(I) atom in 5 and 6 can be oxidized by either 2 equiv of [Cp2Fe][PF6] or an equimolar amount of I2 to afford Mo(II)2M(II)2 complexes, [Mo2M2(X)2(tBuNC)4(pyphos)4]2+ in which two Mo-M(II) single bonds are formed and the bond order of the Mo-Mo moiety has been decreased to three. The Ir(I) complex 5a reacted not only with methyl iodide but also with dichloromethane to afford the 1,4-oxidative addition products [Mo2Ir2(CH3)(I)(tBuNC)4(pyphos)4](Cl)2 (13) and [Mo2Ir2(CH2Cl)(Cl)(tBuNC)4(pyphos)4](Cl)2 (15), respectively, although the corresponding reactions using the Rh(I) analogue 6 did not proceed. Kinetic analysis of the reaction with CH3I suggested that the 1,4-oxidative addition to the Ir(I) complex occurs in an SN2 reaction mechanism.     

In situ AFM studies on self-assembled monolayers of adsorbed surfactant molecules on well-defined H-terminated Si(111) surfaces in aqueous solutions

The formation of self-assembled monolayers (SAMs) of adsorbed cationic or anionic surfactant molecules on atomically flat H-terminated Si(111) surfaces in aqueous solutions was investigated by in situ AFM measurements, using octyl trimethylammonium chloride (C8TAC), dodecyl trimethylammonium chloride (C12TAC), octadecyl trimethylammonium chloride (C18TAC)) sodium dodecyl sulfate (STS), and sodium tetradecyl sulfate (SDS). The adsorbed surfactant layer with well-ordered molecular arrangement was formed when the Si(111) surface was in contact with 1.0x10(-4) M C18TAC, whereas a slightly roughened layer was formed for 1.0x10(-4) M C8TAC and C12TAC. On the other hand, the addition of alcohols to solutions of 1.0x10(-4) M C8TAC, C12TAC, or SDS improved the molecular arrangement in the adsorbed surfactant layer. Similarly, the addition of a salt, KCl, also improved the molecular arrangement for both the cationic and anionic surfactant layers. Moreover, the adsorbed surfactant layer with a well-ordered structure was formed in a solution of mixed cationic (C12TAC) and anionic (SDS) surfactants, though each surfactant alone did not form the well-ordered layer. These results were all explained by taking into account electrostatic repulsion between ionic head groups of adsorbed surfactant molecules as well as hydrophobic interaction between their alkyl chains, which increases with the increasing chain length, together with the increase in the hydrophobic interaction or the decrease in the electrostatic repulsion by incorporating alcohol molecules into the adsorbed surfactant layer, the decrease in the electrostatic repulsion by increasing the concentration of counterions, and the decrease in the electrostatic repulsion by alternate arrangement of cationic and anionic surfactant molecules. The present results have revealed various factors to form the well-ordered adsorbed surfactant layers on the H-Si(111) surface, which have a possibility of realizing the third generation surfaces with flexible structures and functions easily adaptable to circumstances.     

An efficient oxidative lactonization of 1,4-diols catalyzed by Cp*Ru(PN) complexes

[reaction: see text] An efficient oxidative lactonization of 1,4-diols in acetone is accomplished by the well-defined ruthenium catalyst, whose bifunctional nature underlies the high efficiency as well as unique chemo- and regioselectivity of the reaction which provides a rapid access to gamma-butyrolactones including flavor lactones hinokinin, and muricatacin.