derivatives, a weak intermolecular donor-acceptor (D-A) interaction between the quinone (A) and the benzene or methylsubstituted benzene (D) moieties contributes to connect the molecules to a ribbon-like supramolecular unit.1,2 It seems reasonable that the benzene moiety substituted by methyl groups, which is better donor, tend to participate in the D-A interaction preferentially, for example i...

An interface-controlled reaction in normal microemulsions (water/ethanol/sodium oleate/oleic acid/n-hexane) was designed to prepare NaYF4:Yb3+, Er3+ upconversion nanoparticles. The phase diagram of the system was first studied to obtain the appropriate oil-in-water microemulsions. Transmission electron microscopy and X-ray powder diffractometer measurements revealed that the as-prepared nanopar...

Visualizing hydrogen atoms in biological materials is one of the biggest remaining challenges in biophysical analysis. While X-ray techniques have unrivaled capacity for high-throughput structure determination, neutron diffraction is uniquely sensitive to hydrogen atom positions in crystals of biological materials and can provide a more complete picture of the atomic and electronic structures o...

The synthesis of 4-methyl-2,6-di(pyrazol-1-yl)pyridine (L) and four salts of [FeL2]X2 (X(-) = BF4(-), 1; X(-) = ClO4(-), 2; X(-) = PF6(-), 3; X(-) = CF3SO3(-), 4) are reported. Powder samples of 1 and 2 both exhibit abrupt, hysteretic spin-state transitions on cooling, with T1/2↓ = 204 and T1/2↑ = 209 K (1), and T1/2↓ = 175 and T1/2↑ = 193 K (2). The 18 K thermal hysteresis loop for 2 is unusua...

ITAXIUM DIOXIDE may be incorpoT rated into a plastics molding compound to adjust the dielectric constant to a desired value. Either anatase or rutile may be used; these allotropic forms differ in dielectric behavior. Xeither is available commercially in a pure state; a preparation consisting largely of one form is apt to contain, in addition to other impurities, an admixture of the other. In or...

The powder diffractometer at the Australian National Beamline Facility makes extensive use of imaging plates as a detector system. On this instrument, a Weissenberg screen and translatable imaging plate cassette allow a series of up to 35 complete powder patterns to be taken in rapid succession. The high sensitivity and dynamic range of imaging plates mean that exposure times of as little as tw...