Sulfur or Selenium Compounds

It is clear that targeting only the combinations in this table, with no substitution of a trivalent lanthanide for the pnictide, Pn, there are 72 different reactions to monitor, for each sulfur or selenium and arsenic or antimony system, at varying temperatures (our compounds were prepared between 750 and 1200 °C). 

Many of the molecules are chiral. Six of the above-mentioned compounds contain SeSe bonds and no isolated sulfur or selenium atoms (structural units of type —S—Se—S— or —Se—S—Se—), nine contain SeSe bonds and isolated sulfur or selenium atoms, and 13 contain no SeSe bonds. The number of SeS bonds in these molecules can be either 2, 4, 6, or 8. 

The 4,6-diamino-1,3,5-triaza-2-phosphapentalenes are deep red crystalline solids. For reactions, the 4,6-bis(diethylamino) derivative (99) was used (Scheme 34). The compound is not oxidized by air and does not react with sulfur or selenium. Alkylation takes place at the nitrogen atom adjacent to phosphorus. With diethylamine and alcohols no reaction is observed <86CB3213,87PS(30)780>. On simultaneous oxidation by sulfur or selenium, however, alcohols add to the P=N bond yielding... 

Oxidation of the sulfur- or selenium-bridged azepines (171 X=S or Se) with mercury(II) oxide in methanol yields ultimately the 4f/-azepine (68JCS(C)23ll) with hydrogen peroxide as oxidant, the sulfur compound furnishes the sulfoxide (171 X=SO). Selenium dioxide oxidation of 7,8-dimethyl-lf/-l-benzazepin-2-one affords the 2,3-dioxo derivative (173) that displays no evidence of enol tautomers or heteroaromaticity (7ici(L)1439). 

Cyclic compounds containing Si2E2 rings (10.56, E = S, Se) are also formed from the reaction of a stable silylene with sulfur or selenium [eqn (10.37)]. The reaction of the divalent germanium compound Ge[N(SiMe3)2]2 with... 

C1F 54.46 - 155.6/- 100.1 + + + + also usable for synthesis of hypofluorites and oxidative S- or Se-fluorinations of organic sulfur and selenium compounds, frequently in situ preparation of the agent from A -chloro-substituted amides and HF, HF-containing systems or AgF 4, 7... 

The known nonclassical A,B-diheteropentalenes consist of compounds containing an annelated thiophene or selenophene ring, the only uncharged nonradical representations of which contain a tetravalent sulfur or selenium, while the charged structures represent carbonyl, azomethine, thiocarbonyl or selenocarbonyl ylides. The parent systems have not yet been synthesized, only substituted compounds being known. The properties of these substituted derivatives provide a good measure of understanding of the reactivities of the parent systems. 

The reaction of tetrachlorodisilane with chalcogenation reagents is one of the synthetic methods to bis-nor-adamantane or double-decker type compounds. When a solution of di-terf-butyltetrachlorodisilane 66 in THF is refluxed together with one equivalent of lithium sulfide or stirred with lithium selenide at room temperature, the tetra(ferf-butylsilicon)pentachalcogenides 67 and 68, respectively, are formed (Scheme 18)6. Each pentachalcogenide exhibits one resonance of a ferf-butyl group in the H and 13C NMR spectra. Most likely, the bis-nor-adamantane derivatives 69 and 70 are initially formed. Insertion of a sulfur or selenium atom into one of the two strained Si—Si bonds would then lead to the observed products. 

On heating, mixtures of powdered nickel with sulfur or selenium react incandescently. See Sulfur compounds, below... 

Nonmetals. Mixtures of powdered Ni with sulfur or selenium incandesce on heating.11 Organic Solvents. Raney Ni recovered from methanol, ethanol, pentanol, acetone, benzene, cyclohexane, or/vdioxane explodes when heated above 200°C.10 Peroxyformic Acid. Violent explosion with 90% acid.12 Sulfur Compounds. Raney Ni containing the sulfide is pyrophoric.13... 

A,B-Diheteropentalenes have only limited solubility in water. The hydrogen donor properties of the NH site of pyrrole and the hydrogen acceptor property of the oxygen atom of the furan ring can increase the solubility of the compounds containing these heteroatoms relative to the systems with only sulfur or selenium atoms in their structure. Alkylation at the nitrogen of furo[3,2-6]pyrrole derivatives increases the solubility in ethanol and other organic solvents. 

The six-membered ring has a chairlike conformation and the Se—Se bond lengths vary between 229.2 and 237.0 pm. The longest bonds are those originating from the three-coordinated atoms, as has been observed for a number of related sulfur and selenium compounds, e.g., Se102+, S7I+, or S80. 

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