Hydroformylation of formaldehyde

The reaction between hydridotetracarbonylcobalt and monomeric formaldehyde at 0°C in the presence of 1 atm of carbon monoxide leads to stoichiometric hydroformylation with the formation of glycolaldehyde in high yield.     

A new ring opening reaction of N-aminophthalimide hydrazones

Araldehyde hydrazones III of N-aminophthalimide underwent rapid ring opening reactions initiated by the addition of excess base to their refluxing methanolic solutions. The products were conveniently isolated through liquid-liquid extraction as the stable sodium salts V, and acidification precipitated the resulting phthalic acid congeners VI from aqueous solution. Compounds III readily exchanged one hydrazine moiety for another. For example, IIId reacted with 2,4-dinitrophenylhydrazine to give the 2,4-dinitrophenylhydrazone of 4-chlorobenzaldehyde (VIId, 93%). Nonetheless, IIIg reacted exclusively at the carboxaldehyde function to give products VIIIa and VIIIb.     

Mössbauer spectroscopy of R2Fe14B alloys

A Mössbauer study of R₂Fe₁₄B with R=Ce, La, Nd and Gd allowed us to ascribe tentatively hyperfine interaction parameters as hyperfine field and quadrupole splittings to the 6 crystallographically different types of Fe present in the unit cell.     

N-fold joint photocounting distribution for modulated laser radiation: Transmission through the turbulent atmosphere

In this paper a generalised result for theN-fold joint photoelectron counting distribution for independently modulated radiation is given. We extend the recent results of Diament and Teich, for the one-fold photoelectron counting distribution for light propagated through an atmosphere characterised by log-normal irradiance fluctuations, to theN-fold joint photoelectron counting distribution. An approximate solution for thisN-fold distribution is obtained, for detection intervals {T_i} « _a where _a is the characteristic time of the atmospheric turbulence. We present specifically the two-fold joint photocounting distribution for amplitude-stabilised laser radiation passing through such an atmosphere for several levels of turbulence and degrees of correlation. Cases including additive, independent, non-interfering Poisson noise are considered. Computer generated plots of the photocounting distribution are presented. For noise-free detection, the otherwise narrow-peaked photocounting distribution is seen to broaden markedly and shift its peak to lower counts as the turbulence level increases. Furthermore, a non-singular counting distribution is obtained for fully correlated detection. In the presence of additive noise and varying only the signal-to-noise ratio, the probability surface is intermediate between that of the Poisson and that of the noise-free log-normal fading counting distribution. The peak, however, is observed to decrease and then again increase in magnitude as , for correlated detection only. These results are expected to be of use in the study of atmospheric turbulence, as well as in the evaluation of certain stochastic functionals that occur in optical communication theory for the turbulent atmospheric channel.This work was supported in part by the US National Science Foundation under Grant Number NSF-GK-16649.     

Aggregation of equations in integer programming

Several methods for replacing a system of equations (usually linear) in non-negative integer variables by a single equation have recently been proposed. In this paper an attempt is made to extend these results and to clarify the basic structures (in particular in the case of unbounded variables) with emphasis on existence rather than on the difficult problem of optimality. The direct aggregation into fewer constraints (not necessarily one) is studied (avoiding thus the problematic step by step approach) using integral matrices with relatively prime subdeterminants of the largest size. Most of the results are based on the fact that the intersection of a certain linear space with a certain set is bounded. This easy approach (which is characteristic to all known methods except one by Anthonisse and Bradley) may fail for unbounded variables or lead to large coefficients; therefore a method is proposed which under special circumstances may reduce the problem to the solvability of certain congruences.     

Fluorescent sensing and selective Pb(II) extraction by a dansylamide ion-exchanger

The (bis)dansylated sulfonamide 1,2-C6H4(NHSO2C10H6-5-N(CH3)2)2 (1) extracted Pb(II) selectively from water into 1,2-dichloroethane via an ion-exchange mechanism and showed fluorescence quenching upon Pb(II) extraction. The distribution ratios for metal extraction (determined by ICP-MS) for Pb(II) were 133-1410 times higher than those for other metal cations [Co(II), Ni(II), Cu(II), Zn(II), and Cd(II)] under identical conditions. Fluorescence quenching was observed upon Pb(II) extraction, which was dependent on Pb(II) concentration. The monodansylated control, C6H5NHSO2C10H6-5-N(CH3)2 (2), showed neither extraction nor quenching, indicating that the fluorescence effects are a direct result of Pb coordination to 1. The observed selectivity for Pb(II) is ascribed to the formation of a low-coordinate binary Pb(II)-Sulfonamido complex in the organic phase.