Fractal dimension of 3D Ising droplets

At the critical point of the simple cubic Ising model, the radius of Coniglio-Klein clusters containings sites each is found by Monte Carlo simulation to be roughly 0.54s ^0.4, consistent with the theoretically expected fractal dimension 2.5.Dedicated to Professor W. Brenig on the occasion of his 60th birthday     

Carbon-13 nuclear magnetic resonance studies of creatine,creatinine and some of their analogs

Creatine (N-methyl-N-amidinoglycine), creatinine (1-methyl-2-aminoimidazolin-4-one) and a series of 38 of their close structural analogs have been examined using natural abundance ¹³C NMR spectroscopy at 25.16 MHz. Both proton-coupled and proton noise-decoupled spectra were recorded. Unequivocal assignments of the carbon resonances could be made in the vast majority of cases. Both ¹³C NMR chemical shifts and ¹J(CH) values can be used to characterize and to differentiate readily between analogs of creatine and analogs of creatinine. For example, the ¹J(CH) coupling constants for the α-carbons of the acyclic creatine analogs were all in the 140–142 Hz range, whereas the corresponding coupling constants for the related, cyclized creatinine analogs were all in the 150–152 Hz range.     

Vibrational analysis of the sideband of theU-center local mode absorption

A more general coupling of the central ion to its nearest neighbours, than that used so far, is established. Group theoretical argumentation reveals the free choice of 3 parameters instead of one. This especially includes a coupling toT _2g modes, from which it is shown that it is by no means negligible. In this way the agreement to the experimental result can be improved considerably, and an asignment of the peaks in the sideband to the different species of modes is possible. Numerical results are given for KBr.     

Transition metal chelates of two ONNNO quinquedentate ligands

Summary The Schiff bases ,-(RCONHN=CMe)₂C₅H₃N (R = Ph or 2-thienyl) have been prepared by the condensation of 2-acetylpyridine with the substituted hydrazines RCONHNH₂. By the loss of two protons from their iminol tautomers, these Schiff bases act as ONNNO quinquedentate ligands, forming the neutral complexes Met(ONNNO) (Met = Co, Ni, Cu, Zn, Cd or Pd). The zinc and cadmium complexes are monomeric and probably five-coordinate. The cobalt, nickel, and copper complexes are six-coordinate, presumably with an oxygen-bridged dimeric or polymeric structure. The structure of the palladium complex is not known.A uranyl complex UO₂(ONNNO) was also obtained. An x-ray structural determination shows that the complex has a pentagonal bipyrimidal structure with the donor atoms of the quinquedentate Schiff base in the equatorial plane.     

Pressure dependence of the superconducting transition temperature of Th4H15

Measurements of the superconducting transition temperature of Th₄H₁₅ under hydrostatic pressure up to 28 kbar are reported. The initial linear increase is found to be $\text{+42}\text{mK}\text{kbar}$.