Nickel hydrides supported by a non-innocent diphosphine arene pincer: mechanistic studies of nickel-arene H-migration and partial arene hydrogenation

Nickel hydrides supported by a terphenyl diphosphine were synthesized and found to undergo nickel-to-arene H-transfers. Some of the resulting complexes also undergo the reverse (C-to-Ni) H-migration, indicating the potential for storing H-equivalents in this type of pincer ligand. NMR spectroscopy, single crystal X-ray diffraction, and isotopic labeling studies investigating the mechanism of these processes are discussed.     

Series representations for densities functions of a family of distributions—Application to sums of independent random variables

Series representations for several density functions are obtained as mixtures of generalized gamma distributions with discrete mass probability weights, by using the exponential expansion and the binomial theorem. Based on these results, approximations based on mixtures of generalized gamma distributions are proposed to approximate the distribution of the sum of independent random variables, which may not be identically distributed. The applicability of the proposed approximations are illustrated for the sum of independent Rayleigh random variables, the sum of independent gamma random variables, and the sum of independent Weibull random variables. Numerical studies are presented to assess the precision of these approximations.     

Activation of C-H bonds in hydrocarbons by the adduct of activated charcoal with potassium

Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, p. 1214, May, 1989.     

Imidazo [4,5-c] - and [4,5-6] pyridines

The synthesis of novel imidazo[4,5-c]pyridines 11-13 and imidazo[4,5-b]pyridines 18-20 is described using 2 as the starting material. The synthesis is generally applicable for the introduction of a wide variety of substituents.     

Precision heterodyne measurements of ozone spectral lines near 9.5 μm

Precision measurements of 26 individual spectral lines of ozone near 9.5 μm were made using the GSFC infrared heterodyne spectrometer. The line profiles of 26 lines in near coincidence with the emission lines from a ¹²C¹⁶O₂ laser local oscillator were measured at resolving powers of 6 × 10⁶. The retrieved absolute line center frequencies, accurate to ±3 MHz, and the relative line intensities were compared to previous experimental results and theoretical calculations.