Selenium compounds dimer

The formation of the selenium-containing product 141 during the reaction of selenium dioxide with hydroxydio-lefins 140 has been confirmed through the synthesis and reactivity studies with selected model compounds (Scheme 14). The isolation of 8-oxa-3-selenabicyclo[3,2,l]octanes and dimeric selenium compounds has been observed with cyclohexanyl and cyclopentanyl derivatives <1993JOC7942, 1995TL8097>. 

The SeOp4 molecule is distorted trigonal bipyramidal, as shown by the IR, Raman, and F NMR spectra. It is one of the few known hexavalent selenium compounds with fivefold coordination. At temperatures above -100 °C the compound dimerizes to Se202p8 (equation 39). The... 

As expected, the behavior of organozinc-selenium compounds is similar to that of the sulfur analogs. Dimeric self-assembled aggregates, 18, were reported for orga-nozinc diselenocarbamates, [RZnSe2CNR 2]2, R = Me, Et, R = Et [35] and R = MeaCCHj, R = Et ]36]. 

Coordination of [(t-C4H9)2P(=Se)I] with molecular iodine furnishes a 1 1 adduct that crystallises as cyclic dimer in the solid state (Figure 46).57 From each I2 molecule within the structure, one atom acts as acceptor towards selenium, and the other one becomes very weak donor towards the iodine atom bonded to phosphorus. This compound fulfills the requirements of a soft-soft base pair . As in the structure of the parent donor molecule [(t-C4Hg)2P(=Se)I],... 

Gas chromatography and mass spectroscopy (GC/MS) of inorganic and organometallic compounds, 18 273-276 Gaseous hydroxides, 5 215-258 dimerization of, 5 224 mass spectrometric study of, 5 220-225 metalic, 5 220 nonmetallic, 5 217-220 study of in oxyhydrogen flame, 5 225-226 types of, 5 215-217 Gases, see also specific substances high ternperamre species from, 14 137-139 thermal decomposition of, 17 90-93 Gas phase electron resonance spectra, of sulfur and selenium fluorides, 24 190... 

Although selenium derivatives of gold occur less frequently than sulfur ones, the presence of Au- Se intermolecular weak interactions has also been reported in a number of selenium complexes. For example, the cations of the tetranuclear complex [Se(AuPPh3)4](CF3S03)2 [40] are paired across symmetry centers to form loose dimers via an [Au- -Se]2 unit (Figure 5.21), which resembles the supramolecular motif usually found in sulfur compounds of gold. The intermolecular Au---Se... 

Chemical Constitution of Selenium Acetylacetone.—This compound is dimeric and devoid of enolic properties. It combines with acetylacetone to form selenium OC-6i acetylacetone,... 

The dimeric form of selenium benzoylacetone (I) is the product of the simpler condensation (1). The change (2) leads to cz/cZotriselenium benzoylacetone (IV). Hydriodic acid transforms these substances quantitatively into diselenium benzoylacetone (II), the enolic nature of the product being proved by the formation of the copper salt (III). The relationships of these selenium derivatives of benzoylacetone are shown in the following scheme, which also illustrates the formation of the compounds and their quantitative conversion into diselenium bis-benzoylacetone (II) and cyano-3-selenium benzoylacetone (V). 

Electrochemically generated cation radical 252 derived from the cyclic alkylphenyl selenide 251 can react via two parallel paths deprotonization with the formation of compounds containing double bonds in the selenium-bearing rings and homolytic cleavage of the C(sp3)-selenium bond, followed by dimerization and formation of a diselenide 253 with an extended ring (Scheme 38) <1987ZOB609>. 

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