Proton- and metal cation-enhanced excited state intramolecular proton transfers of 2-(2-hydroxyfluorophenyl)benzoxazole having imidazole moiety

2-(2-Hydroxyfluorophenyl)benzoxazole having an imidazole moiety 1 was synthesized by the two step reactions starting from 2-(pentafluorophenyl)benzoxazole. Protonation at the 3-imidazole nitrogen atom of 1 enhances the green emission around 500 nm, where the positive character caused by the protonation is inductively communicated to the hydroxy group, to recover its intramolecular hydrogen bonding, leading to the ESIPT process. Addition of Al³⁺ or Zn²⁺ to 1 enhances both the green emission and the blue emission around 450 nm in chloroform-acetonitrile.     

Development of new WC–Ni hardmetals for use in high pressure experiments

Ultrafine-grained (0.2–0.3?µm) WC–Ni hardmetals with a low Ni content (3–5?wt%) were developed using new production techniques based on adding an appropriate amount of VC and Cr₃C_2, combined with the strong mixing of raw materials. Their uniaxial compressibility was subsequently compared with that of existing WC–Ni and WC–Co hardmetals to assess their suitability for use as anvils in various high pressure experiments, particularly those associated with neutron or magnetic studies. The ultimate compressive strength of the newly developed hardmetals was over 7.7?GPa, which was higher by 1.2?GPa than that of the existing WC–Ni hardmetal ‘MF10’. When these hardmetals were used as anvils, a pressure of approximately 16?GPa was generated using a Paris-Edinburgh-type apparatus with φ8?mm culet, thereby proving that they can allow the physical properties of various materials to be measured at higher pressures than is possible with existing hardmetals.     

Synthesis of polycarbosilanes having a five‐membered cyclic carbonate structure and their application to prepare gel polymer electrolytes for lithium ion batteries

A silacyclobutane having a five‐membered cyclic carbonate structure (SBMC) was prepared, and its transition metal‐catalyzed ring‐opening polymerization at the four‐membered carbosilane unit was investigated as well as formation of carbosilane networked polymers and polymer gel electrolytes. The SBMC was synthesized by epoxidation of 1‐(4‐butenyl)‐1‐methylsilacyclobutane followed by insertion of CO₂ to the epoxide. Ring‐opening polymerization of the silacyclobutane moiety in the SBMC readily proceeded by a transition metal catalyst such as platinum divinyltetramethyldisiloxane complex. A flexible networked polymer film was obtained by copolymerization of the SBMC with a small amount of crosslinker, hexamethylene‐1,6‐bis(1‐methylsilacyclobutane) (HMBS). The copolymerization of SBMC and HMBS in 1 M LiPF₆ solution in ethylene carbonate and diethyl carbonate (3/7 v/v) gave a gel polymer electrolyte, which showed good ionic conductivity and could be applied to lithium ion batteries. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Supramolecular Complexation of N‐Alkyl‐ and N,N′‐Dialkylpiperazines with Cucurbit[6]uril in Aqueous Solution and in the Solid State

Water seeds : Complex stoichiometry/composition and degree of oligomerization (oligomeric supramolecular complex formation) of cucurbit[6]uril (CB[6]) with N‐alkyl‐ and N,N′‐dialkylpiperazine were investigated in aqueous solutions by means of isothermal titration calorimetry (ITC), ESI‐MS, NMR and light scattering measurements.

     

Analysis of MS/MS fragmentation of taxoids

The fragmentation pathways of seven types of taxoids were investigated by using a LC-MS/MS method, namely: (1) neutral taxoids with a C-4(20) double bond; (2) taxoids with a C-4(20) double bond and oxygenation at C-14; (3) 5-cinnamoyl taxoids with a C-4(20) double bond; (4) a basic taxoid with a C-4(20) double bond; (5) a taxoid with a C-4(20) epoxide; (6) taxoids with an oxetane ring; and (7) taxoids with an oxetane ring and a phenylisoserine C-13 side chain. Depending on the class of core structure and the substitution pattern, each taxoid gave either the molecular adduct ion [M+NH4]+ or [M+H]+. In the MS/MS, the molecular adduct ion gave characteristic product ions corresponding to the loss of water, acetic acid, benzoic acid, and cinnamic acid or the phenylisoserine group. These could reflect the difference of the substitutions and structural modifications and should be utilized for the structure elucidation oftaxoids by LC-MS.     

The reaction of five-membered cyclic trithiocarbonates with n-butyllithium

It was found that the reaction of five-membered cyclic trithiocarbonates with n-butyllithium in tetrahydrofuran is applicable to the preparation of unsymnetrical linear trithiocarbonates and further to the interconversion of cis- and trans-olefins.     

The separation of oligodeoxynucleotides having a single-base difference by affinity capillary electrophoresis using oligodeoxynucleotide- polyacrylamide conjugate

We have developed an affinity capillary electrophoresis for gene mutation assay. We show a method for separating a mixture of oligodeoxynucleotides having single-base difference using oligodeoxynucleotide-polyacrylamide conjugate. Because the conjugate behaved similarly to nonionic polyacrylamide in terms of migration rate, it can be used as a pseudoimmobilized affinity ligand in a polyacrylamide-coated capillary. Oligodeoxynucleotide having an oncogene sequence and a version with one base substituted were completely separated by this method. The magnesium-ion concentration was found to be a key factor in achieving efficient separation of oligodeoxynucleotides with the same chain length.