A Structural Comparison of Organoterminated Selenide, Diselenide, and Triselenide

Abstract

A series of organosubstituted mono-, di-, and triselenides has been prepared and structurally characterized. In this series, a novel modification of 1,2,3-triselena- [3]ferrocenophane has been obtained in which intermolecular contacts between the central selenium atoms are below the sum of the van der Waals radii. Moreover, dimesitylselenide has been structurally characterized.

Contrasting Reactivity of 2‐chloro‐1‐formyl‐3‐hydroxymethylenecyclohexene and its Schiff Bases towards Disodium Diselenide: Isolation of Selenospirocycles versus Azapentalenes

“…In this procedure, sodium metal was reacted with an equivalent quantity of elemental selenium in dry THF in the presence of catalytic amount of naphthalene. It is worth pointing out that due to the tendency of catenation, there are possibilities for the formation of multiple polyselenides –. In this context, the procedure reported by Thomson et al .…”

Synthesis and Single‐Electron Oxidation of Bulky Bis(m‐terphenyl)chalcogenides: The Quest for Kinetically Stabilized Radical Cations

“…[25] The 125 Te NMR spectrum of 1 c exhibits a signal at δ = 572.0 that lies midway between those of Ph 2 Te (δ = 707) and Mes 2 Te (δ = 275). [26] The molecular structures of 1 a, 1 b and 1 c show the large steric encumbrance of the bulky m-terphenyl substituents, [27] which, however, has only a small effect on the average EÀ C bond lengths (E = S, Se, Te) that are only slightly elongated compared to Mes 2 S (1.787(1) vs. 1.785(1) Å), [28] Mes 2 Se (1.944(4) vs. 1.931(1) Å) [29] and Mes 2 Te (2.150(1) vs. 2.140(3) Å). [30] The effect is more pronounced for the CÀ EÀ C angles of 1 a-c, which are considerably larger than those of Mes 2 S (114.5(1) vs. 106.4(1)°), [28] Mes 2 Se (116.1(2) vs. 102.0(1)°) [29] and Mes 2 Te (116.2(2) vs. 101.0(1)°).…”

“…[26] The molecular structures of 1 a, 1 b and 1 c show the large steric encumbrance of the bulky m-terphenyl substituents, [27] which, however, has only a small effect on the average EÀ C bond lengths (E = S, Se, Te) that are only slightly elongated compared to Mes 2 S (1.787(1) vs. 1.785(1) Å), [28] Mes 2 Se (1.944(4) vs. 1.931(1) Å) [29] and Mes 2 Te (2.150(1) vs. 2.140(3) Å). [30] The effect is more pronounced for the CÀ EÀ C angles of 1 a-c, which are considerably larger than those of Mes 2 S (114.5(1) vs. 106.4(1)°), [28] Mes 2 Se (116.1(2) vs. 102.0(1)°) [29] and Mes 2 Te (116.2(2) vs. 101.0(1)°). [30] We also studied the stepwise reaction of TeF 4 with 2,6-Mes 2 C 6 H 3 Li to shed light on the intermediates leading to the formation of 1 c. At an equimolar ratio this reaction afforded the mono-substituted m-terphenyl tellurium trifluoride 2,6-Mes 2 C 6 H 3 TeF 3 (3) in 61 % yield.…”

Ultrasound-assisted synthesis of alkali metals diselenides (M2Se2) and their application for the gram-scale preparation of 2,2'-diselenobis(benzoic acid)

“…[6][7][8][9] In addition, aromatic diselenides exert interesting biological activities. 10,11 As shown in Figure 1, the methods reported for their synthesis can be clustered into three groups: (A) decomposition of selenides, 12 selenyl azides, 13 selenocyanates 14 and selenyl halides; 15 (B) nucleophilic displacement of leaving units, as exemplified in electron withdrawing group (EWG)-containing aromatic halides or diazonium salts, both operated by alkali metal diselenides (M2Se2) and (C) reaction between a carbon nucleophile, either an organolithium 16 or a Grignard reagent, 17 and elemental selenium. Among the three pathways we focused our attention to route B.…”