Die Kristallstruktur und das Raman‐Spektrum von SbCl₃ · S₈

Abstract

Bei der Reaktion von SbCl5 mit CS2 bei 5°C entsteht nicht (wie in der Literatur beschrieben) SbSCl3 sondern SbCl3 · S8. Dieses zersetzt sich bereits bei Zimmertemperatur allmählich zu SbCl3 und Schwefel. Nach der Kristallstrukturbestimmung ist es aus pyramidalen SbCl3‐ und kronenförmigen S8‐Molekülen aufgebaut; Paare von SbCl3‐Molekülen bilden schwach assoziierte dimere Einheiten, außerdem gibt es einige relativ kurze Sb…︁S‐Kontakte. SbCl3· S8 kristallisiert triklin in der Raumgruppe P1 mit den Gitterkonstanten a = 805, b = 867, c = 1073 pm, α = 94,9, β = 107,1 und γ = 111,6° (bei −5°C). Die Kristallstruktur wurde mit 2032 Röntgenreflexen bestimmt und bis zu einem Übereinstimmungsindex von R = 2,8% verfeinert. Das Raman‐Spektrum wird mitgeteilt.

Coordination ofcyclo-Octasulfur andcyclo-Heptaselenium to Dinuclear Rhenium(I) Systems

“…Found: C, 5.5; Se, 40.8. 13 C NMR (CS 2 , 20 °C): δ ) 187.1, 184.5, 182.6 (CO). 77 Se NMR (CS 2 , 20 °C): δ ) 1150, 1011, 973, 927 (2 Se, 2 Se, 2 Se, 1 Se).…”

“…The NMR spectra were measured on Bruker AC-250 (5.87 T) and Varian Gemini-200 BB (4.7 T) instruments. 13 C, 31 P, and 77 Se NMR chemical shifts were referenced to SiMe 4 , H 3 PO 4 , and SeMe 2 , respectively. Re 2 (µ-Br) 2 (CO) 6 (THF) 2 44a and Re 2 (µ-I) 2 -(CO) 6 (THF) 2 45 were prepared as reported in the literature.…”

“…Chalcogens E n in their reaction with metal-containing complexes usually yield polychalcogenides, because of (a) the oxidizing power of E n , (b) the relatively easy cleavage of the E−E bond, and (c) the potentially high hapticity of the resulting chalcogenide ligand. On the other hand, weak sulfur−halide or sulfur−sulfur interactions are responsible for the formation of the following crystallographically established adducts: CHI 3 ·3S 8 , SnI 4 ·2S 8 , AI 3 ·3S 8 (A = Sb, As), SbCl 3 ·S 8 , Ti 4 O(S 2 ) 4 Cl 6 ·2S 8 , WCl 6 ·S 8 , WCl 4 S(THF)·S 8 ,16a WCl 4 S·S 8 ,16b S 4 (NH) 4 ·3S 8 , Co 6 (μ 3 -S) 8 (CO) 6 ·3S 8 , (PPh 4 ) 4 (Ag 2 S 20 )·S 8 , and [(PPh 3 ) 2 N][Ag(S 9 )]·S 8 . In these compounds, S 8 displays weak interactions with some peripheral atoms of the coordination sphere rather than with the central metal atom.…”

Pnictogen‐Bonding Catalysts, Compared to Tetrel‐Bonding Catalysts: More Than Just Weak Lewis Acids

“…‘Weakly binding ligands,’ for instance, can possibly be synonymous with ‘pnictogen‐bond acceptors.’ Like with hydrogen bonds and Brønsted acids, [56–60] the range between non‐covalent pnictogen bonds and covalent Lewis acids is a continuum, with situations at the edge the most difficult to classify ( Scheme 1). Moreover, characteristics depend on partners, weak enough pnictogen‐bond acceptors will convert powerful Lewis acids like SbCl 3 into a pnictogen‐bond donor [109] . Examples for confirmed or possible contributions of pnictogen bonds to classical Lewis acid catalysis include asymmetric conjugate additions [110] and aza‐ Diels–Alder reactions [108] catalyzed by proline‐based aminophosphine oxides, Mannich reactions with most significant, air‐stable and water‐tolerant azastibocines, [111] nucleophilic substitution of propargyl alcohols, [112,113] certain Mukaiyama aldol condensation with chiral bipyridines binding to bismuth triflate, [114,115] antimony‐templated macrolactamizations by Ishihara , Yamamoto and co‐workers [116] or recent fluorination of phenyl boronic acids by Cornella and coworkers [117] …”

“…Moreover, characteristics depend on partners, weak enough pnictogen-bond acceptors will convert powerful Lewis acids like SbCl 3 into a pnictogen-bond donor. [109] Examples for confirmed or possible contributions of pnictogen bonds to classical Lewis acid catalysis include asymmetric conjugate additions [110] and aza-Diels -Alder reactions [108] catalyzed by proline-based aminophosphine oxides, Mannich reactions with most significant, air-stable and water-tolerant azastibocines, [111] nucleophilic substitution of propargyl alcohols, [112,113] certain Mukaiyama aldol condensation with chiral bipyridines binding to bismuth triflate, [114,115] antimony-templated macrolactamizations by Ishihara, Yamamoto and co-workers [116] or recent fluorination of phenyl boronic acids by Cornella and coworkers. [117] Besides altered charge distribution, the difference between pnictogen-bonding and Lewis acid chemistry originates from different environment (Figures 1 and 2, Scheme 1).…”