Structure du morpholino o-nitrobenzènesélénénamide

Abstract

Abstract. C10H12N203Se, Mr= 286.96, triclinic, Pi, a=8.039(1), b=8.832(2), c= 9.283 (2),/~, a=

Origin of Stereoselectivities in Asymmetric Alkoxyselenenylations

“…Investigations of more than 40 published crystal structures of organic, inorganic, and organometallic compounds containing multivalent selenides reveal that internal or external nucleophiles, such as the oxygens of nitro, carboxylate, hydroxy, or methoxy groups approach selenium along the extension of one of the bonds to selenium. For example, morpholino( o -nitrophenyl)selenide (Figure a) has planar geometry, where the oxygen of the nitro group contacts selenium with a distance of 2.576 Å, and the angle of oxygen−selenium−carbon of cyclohexyl is 171° . The geometry of morpholino( o -nitrophenyl)selenide is similar to the B3LYP/3-21G optimized geometries of 8 and 13 .…”

Zero-, one-, two- and three-dimensional supramolecular architectures sustained by Se…O chalcogen bonding: A crystallographic survey

“…There are a total of 32 selenium(II) species, 1 – 32 [11] , [73] , [74] , [75] , [76] , [77] , [78] , [79] , [80] , [81] , [82] , [83] , [84] , [85] , [86] , [87] , [88] , [89] , [90] , [91] , [92] , [93] , [94] , [95] , [96] , [98] , [99] , [100] , [101] , forming Se … O contacts leading to zero-dimensional aggregates. The chemical diagrams for the interacting species in these structures are shown in Fig.…”

“…The overwhelming majority of mono-nuclear selenium(II) molecules in this category adopt a two-molecule motif sustained by two Se … O contacts. This motif is found in the crystals of 10 – 27 [81] , [82] , [83] , [84] , [85] , [86] , [87] , [88] , [89] , [90] , [91] , [92] , [93] , [94] , [95] , [96] . Molecules 10 – 12 feature acyclic, two-coordinated selenium, 13 is a selenide and those of 14 – 27 are also two-coordinated but with the selenium atom incorporated within a ring.…”

“…In 10 [81] and 20 [91] the Se … O interactions occur between the two independent molecules comprising the asymmetric unit whereas in the remaining examples, they occur between centrosymmetrically related molecules. The selenium atoms in 10 [81] and 12 [83] , Fig. 3 e, associate with nitro-oxygen atoms, in 11 [82] with carbonyl-oxygen, Fig.…”

Sparing the ortho‐position in nucleophilic aromatic substitution‐specific displacement of the 4‐SePh group in 2,4‐bis(phenylseleno)nitrobenzene

“…1 [5]. (The lengths of the Se· · ·O interactions in nine reported similar structures are in the region 2.3-2.7Å.).…”