[2 + 2] Cycloaddition of Carbon Disulfide to NCN-Chelated Organoantimony(III) and Organobismuth(III) Sulfides: Evidence for Terminal Sb−S and Bi−S Bonds in Solution

Abstract

The organoantimony(III) and organobismuth(III) sulfides (LMS)2 (L = NCN chelating ligand, C6H3-2,6-(CH2NMe2)2; M = Sb (1), Bi (2)) are dimeric in the solid state. Nevertheless, their monomeric structures with terminal Sb−S and Bi−S bonds present in solution were trapped by [2 + 2] cycloaddition reactions with CS2, giving the molecular trithiocarbonates LMS2CS (M = Sb (3), Bi (4)). Both compounds were characterized in the solid state by X-ray diffraction techniques on both single crystals and powder material and by IR spectroscopy. Carbon disulfide can be easily eliminated from the trithiocarbonates 3 and 4 by heating to 120 °C (for 3) and 160 °C (for 4) to recover the starting sulfides 1 and 2. In solution, trithiocarbonates 3 and 4 exist in equilibrium with starting sulfides 1 and 2, but this equilibrium may be shifted to pure 3 and 4 by addition of an excess of CS2, as shown by 1H NMR spectroscopy.

Synthesis and Structure of NCN‐Chelated Organobismuth(III) Bis‐Pentasulfide

“…Dichloromethane was dried with CaH 2 and distilled prior to use. Starting sulfide 1 was prepared as described in literature 5. The 1 H and 13 C NMR spectra were recorded with a Bruker 400 spectrometer, using 5 mm tunable broad‐band probe.…”

“…By analogy, we have shown that organoantimony and organobismuth sulfides (L M S) 2 {L = [2, 6‐(CH 2 NMe 2 ) 2 C 6 H 3 ] – , M = Sb, Bi ( 1 )}, which are split to their monomeric forms with terminal M –S bonds in solution, are able to activate carbon disulfide5 and in the case of the antimony compound also elemental sulfur 6. Herein, we report activation of S 8 by organobismuth sulfide ( 1 ) with formation of unprecedented cyclic bis‐pentasulfide LBi(μ‐S 5 ) 2 BiL ( 2 ).…”

Synthesis, Structure and Applications of Hypervalent Organoantimony Compounds Having Intramolecular E→Sb (E = N, O, S) Coordinations

“…The dimeric oxide 59 reacted with CO 2 in a toluene solution to give carbonate ArSbCO 3 (61) (Scheme 19). In order to demonstrate that the antimony sulfide (ArSbS) 2 (60) dissociates in solution to monomeric species ArSbS with a terminal Sb-S bond, trithiocarbonate ArSbS 2 C=S (62) was obtained by treating 60 in CH 2 Cl 2 solution with an excess amount of CS 2 (Scheme 19) [71]. The molecular structures of all four compounds were determined by single-crystal XRD analysis.…”

Carbon–Carbon Bond Forming Reactions Promoted by Aluminyl and Alumoxane Anions: Introducing the Ethenetetraolate Ligand

“…[9] We propose that the postulated sulfide is highly reactive and undergoes [2+2]-cycloaddition with a second equivalent of CS 2 to afford 1 ({c}: E = S) via Pathway 1 (Scheme 2). Such reductive disproportionation of CS 2 in situ is unusual in main group chemistry, [10] although the [2+2]cycloaddition of CS 2 to terminal Ge=S, [11] bridging M(m-S) 2 M (M = Sb, Bi), [12] and in situ generated Sn = S [13] bonds has produced a family of p-block trithiocarbonate compounds, equivalent to step {b} ! {c}.…”

“…(i) CS 2 (2 equiv, hexane, 298 K); (ii) 0.5 S 8 ; (iii) CS 2 (4 equiv, toluene, 195 K). 7, Al1-S2 2.3077 7, Al2-S4 2.3076 7, Al2-S5 2.3201-(7), C1c-S1 1.744(2), C1c-S2 1.742(2), C1c-S3 1.661(2), C2c-S4 1.739(2), C2c-S5 1.739(2), C2c-S6 1.668(2); S1-Al1-S2 78.11(2), S4-Al2-S5 78.03(2), S1-C1c-S2 113.45 (12), S1-C1c-S3 122.59(13), S2-C1c-S3 123.95 14, S4-C2c-S5 113.80 (11), S4-C2c-S6 123.16 (12), S5-C2c-S6 123.03 (12). Scheme 2.…”