Synthesis and Structure of Bis(para‐methoxyphenyl)selenoxide and its Monohydrate. Theoretical Considerations of the Hydration of Diorganoselenium Oxides
Abstract:The title compound was prepared by base hydrolysis of (p‐MeOC6H4)2SeCl2 in water and isolated as the crystalline monohydrate, (p‐MeOC6H4)2SeO·H2O, in which the water molecule is associated via hydrogen‐bonding. Water‐free (p‐MeOC6H4)2SeO was obtained crystalline after drying and recrystallisation from toluene. Both crystal phases were investigated by single crystal X‐ray diffraction. Preliminary DFT calculations at the B3LYP/LANL2DZdp level of theory suggest that the hydrogen bonded complexes R2SeO·H2O (R = H,… Show more
“…The chemical diagrams for these species, i.e. 160 – 180 [93] , [104] , [105] , [113] , [188] , [206] , [207] , [208] , [209] , [210] , [211] , [212] , [213] , [214] , [215] , [216] , [217] , are shown in Fig. 15 .…”
Section: One-dimensional Assembles Mediated By Se
…
mentioning
confidence: 99%
“…The three selenoxides, 160 [104] , 161 [104] and 162 [206] , Fig. 16 a, feature C 2 O-donor sets and associate in their crystals to form linear, supramolecular chains via Se … O(nitro) interactions in 160 , and Se … O(methoxy) interactions in 161 and 162 .…”
Section: One-dimensional Assembles Mediated By Se
…
mentioning
Highlights
Selenium
…
oxygen chalcogen bonding is important in relevant crystal structures.
Se
…
O interactions, operating alone, are found in 13% of possible structures.
Se
…
O(carbonyl) interactions occur in 50% of possible structures.
Zero-, one-, two- and three-dimensional architectures are sustained by Se
…
O interactions.
One-dimensional chains are found in 55% of examples.
“…The chemical diagrams for these species, i.e. 160 – 180 [93] , [104] , [105] , [113] , [188] , [206] , [207] , [208] , [209] , [210] , [211] , [212] , [213] , [214] , [215] , [216] , [217] , are shown in Fig. 15 .…”
Section: One-dimensional Assembles Mediated By Se
…
mentioning
confidence: 99%
“…The three selenoxides, 160 [104] , 161 [104] and 162 [206] , Fig. 16 a, feature C 2 O-donor sets and associate in their crystals to form linear, supramolecular chains via Se … O(nitro) interactions in 160 , and Se … O(methoxy) interactions in 161 and 162 .…”
Section: One-dimensional Assembles Mediated By Se
…
mentioning
Highlights
Selenium
…
oxygen chalcogen bonding is important in relevant crystal structures.
Se
…
O interactions, operating alone, are found in 13% of possible structures.
Se
…
O(carbonyl) interactions occur in 50% of possible structures.
Zero-, one-, two- and three-dimensional architectures are sustained by Se
…
O interactions.
One-dimensional chains are found in 55% of examples.
“…(inset) Crystal structure of ( p -MeOC 6 H 4 ) 2 SeO···H 2 O showing the hydrogen bonding similar to the hydrogen bonding calculated for 4 . The inset structure was redrawn from reference using the Mercury software program.…”
Combination of the dithiol N,N'-bis(2-mercaptoethyl)isophthalamide, abbreviated as BDTH2 and as 1, with excess H2SeO3 in aqueous acidic (pH ≈ 1) conditions resulted in precipitation of BDT(S-Se-S) (6), with a (77)Se NMR chemical shift of δ = 675 ppm, and oxidized BDT. When the reaction is conducted under basic conditions Se(IV) is reduced to red Se(0) and oxidized 1. No reaction takes place between 1 and selenate (Se(VI)) under acidic or basic conditions. Compound 6 is stable in air but decomposes to red Se(0) and the disulfide BDT(S-S) (9) with heating and in basic solutions. Mechanisms and energetics of the reactions leading to 6 in aqueous solution were unraveled by extensive calculations at the ωB97X-D/aug-cc-pVTZ-PP level of theory. NMR chemical shift calculations with the gauge-independent atomic orbital (GIAO) method for dimethyl sulfoxide as solvent confirm the generation of 6 (calculated δ value = 677 ppm). These results define the conditions and limitations of using 1 for the removal of selenite from wastewaters. Compound 6 is a rare example of a bidentate selenium dithiolate and provides insight into biological selenium toxicity.
“…This parallels the well-known tendency of the oxides to exist as hydrates in water solution because of stabilization of the chalcogen-oxygen single bonds. [44][45][46] While sulfoxides do not form hydrates, the corresponding telluroxides are completely hydrated in water. The selenoxides are stabilized by hydrogen bonding to a water molecule, as demonstrated by both X-ray crystallography and DFT calculations.…”
Section: Chemical and Configurational Stabilitymentioning
confidence: 99%
“…The selenoxides are stabilized by hydrogen bonding to a water molecule, as demonstrated by both X-ray crystallography and DFT calculations. 45 It was early recognized that spirochalcogenuranes could readily undergo a Berry pseudorotation 47 (BP) process, since a variable temperature 19 F-NMR spectrum of compound 15a (Scheme 7) showed four resonance signals below 21008C but only two at higher temperatures. 48 This signal collapse was attributed to a fast exchange within the exo-and the endo-located trifluoromethyl groups, respectively.…”
Section: Chemical and Configurational Stabilitymentioning
A summary of the present knowledge of the stereochemistry of the hypervalent spirochalcogenuranes, especially the role of the central atom (S, Se, Te) for the chemical and configurational stability and the chiroptical and X-ray crystallographic techniques available for the determination of absolute configuration, is given.
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