Trivalent samarium

The compounds of trivalent samarium (Sml2Y) do not take part in chain... 

Samarium may be analyzed by spectrographic and spectrophotometric methods. In solution, the trivalent samarium shows sharp and intense absorption bands at 362.5, 347.5 and 402.0 nm. Trace analysis may be carried out most accurately by flame AA, ICP-AES, ICP/MS and neutron activation analysis. ICP/MS is the most sensitive method. The metal and its insoluble salts may be solubilized by digestion with acids and diluted appropriately for most instrumental measurements. 

Trivalent samarium activated minerals usually display an intense luminescence spectrum with a distinct hne structure in the red-orange part of the spectrum. The radiating term 65/2 is separated from the nearest lower level 11/2 by an energy interval of 7,500 cm This distance is too large compared to the energy of phonons capable to accomplish an effective non-radiative relaxation of excited levels and these processes do not significantly affect the nature of their spectra in minerals. Thus all detected lines of the Sm " luminescence take place from one excited level and usually are characterized by a long decay time. 

Ihara, E. Yoshioko, S. Furo, M. Katsura, K. Yasuda, H. Mohri, S. Kanehisa, N. Kai, Y. Synthesis and olefin polymerization catalysts of new trivalent samarium and yttrium complexes with bridging bis(cyclopentadienyl) ligands. Organometallics 2001, 20, 1752-1761. 

Stimulated emission has not been reported for trivalent samarium in any medium. There are numerous absorption bands at wavelengths 500 nm, and efficient fluorescence occurs from the F5/2 level. However, the emission is divided among many terminal levels and several self-quenching transitions are possible. The probability for excited-state absorption from F5/2 may, in many cases, be stronger than for stimulated emission. 

It has been recently shown [11] that a Swern oxidation followed by an intramolecular Tischenko reaction gives access to L-idose or L-altrose derivatives from the corresponding protected hexos-5-uloses. As can be seen from Scheme 6, D-glucitol 14 was oxidised to aldulose 15 via a Swern oxidation. Subsequently, this compound was treated with a trivalent samarium reagent (tert-BuOSml2), thereby inducing a Tischenko reaction, which led to L-fdo-configured ferf-butyl... 

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