Synthesis and characterization of a highly strained donor–acceptor nanohoop

A highly-strained, nitrogen-doped cycloparaphenylene (CPP), aza[6]CPP, was synthesized and then converted to a donor–acceptor nanohoop, N-methylaza[6]CPP, via alkylation of the nitrogen center.

Bridging the opposite chemistries of tantalum and tungsten polyoxometalates

Reaction of Ta peroxometalate and tungstate affords the first systematic series of Ta/W isopolyoxometalates. An analogous reaction system yields a Nb/W cluster. The electronic structure and stability of these clusters varies as a function of the group V metal content, as inferred from spectroscopic, electrochemical and mass-spectrometry analysis and confirmed by DFT calculations.

New A2/3-xRh2O4 compounds with the CaFe2O4 structure where A is a rare earth or Bi

New compounds of the type R(2/3-x)Rh(2)O(4) with the CaFe(2)O(4) structure have been prepared, where R is a rare earth. For crystals grown in a Bi/V/O flux, the rare earth was partially replaced by Bi. No evidence of ordering of the A cation vacancies is found, but the A cations are displaced from the ideal A cation site by about 0.24 A. Electrical conductivity measurements on crystals suggest that the materials are degenerate semiconductors with Seebeck measurements showing p-type behavior. This is consistent with our observation that x in R(2/3-x)Rh(2)O(4) ranges up to about 0.09. The compounds were also characterized by magnetic susceptibility and diffuse reflectance measurements.

Bis(mu-3,5-di-tert-butylcatecholato-O1:O1,O2)bis[tris(pyridine-N)cadmium(II)] dipyridine solvate

X-ray diffraction shows that the title cadmium(II) complex, [Cd(2)(C(14)H(20)O(2))(2)(C(5)H(5)N)(6)].2C(5)H(5)N, has a dimeric structure in which two (py)(3)Cd(3,5-di-tert-butylcatecholate) units (py is pyridine) are connected by two bridging O atoms, the coordination of the Cd atoms being distorted octahedral. There are two symmetrically independent dimers in the crystal structure; one is in a general position and the other lies about an inversion centre. In both cases, the bridging Cd-O distances between the Cd-catecholate units [2.224 (2)-2.237 (2) A] are shorter than the bridging Cd-O distances within the catecholate cycle [2.273 (2)-2.281 (2) A]. The Cd-N(py) distances are 2.354 (2)-2.471 (2) A. Besides the main molecules, the crystal also contains pyridine solvate molecules.