Bis(1,2-dimethoxyethan-O,O′)lithium-phosphanid, -arsanid und -chlorid – drei neue Vertreter des Bis(1,2-dimethoxyethan-O,O′)lithium-bromid-Typs

Abstract

Bei Versuchen zur Isolierung des thermisch instabilen Lithium‐silylphosphanids schieden sich bei –60 °C aus 1,2‐Dimethoxyethan Einkristalle des bisher unbekannten Dismutierungsproduktes Bis(1,2‐dimethoxyethan‐O,O′)lithium‐phosphanid (1) ab. Das homologe Arsanid 2 kristallisierte aus, nachdem eine bei –78 °C eingefrorene Lösung von Arsan im selben Lösungsmittel mit Lithium‐n‐butanid behandelt worden war. Ebenso unerwartet fielen bei Reaktionen von 1‐Chlor‐2,2‐bis(trimethylsilyl)‐1λ3‐phosphaethen mit (1,2‐Dimethoxyethan‐O,O′)lithium‐bis(trimethylsilyl)stibanid bzw. von Lithium‐1,2,3,4,5‐pentaphenyl‐2,3‐dihydro‐1λ3‐phosphol‐3‐id mit ω‐Bromstyrol in 1,2‐Dimethoxyethan das analog zusammengesetzte Chlorid 3 und Bromid 4 an. Die monomeren Komplexe 1 {–100 ± 3 °C; a = 1391,1(4); b = 809,8(2); c = 1249,1(3) pm; β = 102,84(2)°}, 2 {–100 ± 3 °C; a = 1398,3(4); b = 819,8(3); c = 1258,5(4) pm; β = 103,35(2)°} und 3 {–100 ± 3 °C; a = 1308,4(2); b = 788,2(1); c = 1195,6(1) pm; β = 95,35(1)°} kristallisieren in der monoklinen Raumgruppe C2/c mit vier solvatisierten Ionenpaaren in der Elementarzelle und sind isotyp zum bereits von Rogers u. a. [13] bei Zimmertemperatur untersuchten Bis(1,2‐dimethoxyethan‐O,O′)lithium‐bromid (4) {–73 ± 2 °C; a = 1319,0(2); b = 794,1(1); c = 1214,3(2) pm; β = 96,22(1)°}. In den trigonal‐bipyramidal koordinierten Neutralkomplexen der Symmetrie C2 besetzen die Pnikogenanid‐ bzw. Halogenid‐Anionen äquatoriale Positionen {Li–P 260,4(4); Li–As 269,8(6); Li–Cl 238,6(7); Li–Br 256,3(10) pm}, während die Chelatliganden äquatoriale und axiale Lagen überbrücken {Li–Oeq 205,4(4) bis 207,4(4); Li–Oax 208,9(3) bis 215,5(2) pm}. Die Koordination im (dme)2Li‐Fragment, die Li–X‐Abstände (X = P, As, Cl, Br), die Struktur der Chelatringe und die Packung der Neutralkomplexe werden im Detail diskutiert.

Homoleptic Tris(α,ω-alkanediyl)yttriates of the Type [{Li(dme)}3{Y(CH2-X-CH2)3}] (X = C2H4, C3H6, Si(CH3)2)

“…This precipitate was collected by filtration and subsequent cooling of the filtrate to −40 °C leads to the formation of a second single-crystalline crop of [{Li(dme)} 3 {Y(C 4 H 8 ) 3 }] ( 2 ) and [{Li(dme)} 3 {Y(C 5 H 10 ) 3 }] ( 3 ). In the case of 3 , the product is contaminated by [(dme) 2 LiBr], present from the synthesis of the lithium reagent.…”

“…Six grams (66.6 mmol) of DME were added to the filtrate, and an oily substance formed wherein crystals slowly grew at −40 °C. This substance was a mixture of crystals of [(dme) 2 LiBr] and 3 . LiBr stems from the synthesis of the starting organolithium compound.…”

Coordination Behavior of Calcocene and Its Use as a Synthon for Heteroleptic Organocalcium Compounds

“…The remaining precipitate consisted mainly of insoluble LiCp. The solution was stored at -20 °C, and crystals of [(dme) 2 LiBr] 27 initially precipitated (LiBr originates from the preparation of LiPh via direct synthesis of lithium with bromobenzene). Further cooling and fractional crystallization was necessary to remove this byproduct completely.…”

Metalated Oligosilanylstibines

“…The compound was isolated as etherate and can be used as nucleophilic building block that is easily silylated with trimethylchlorosilane. The obtained trimethylsilylated stibine 5 reacts with potassium tert-butoxide to yield cleanly a potassium stibide (6). Another potassium stibide (8) was formed in the reaction of the tris-(trimethylsilyl)silylated derivative of the stibacyclopentasilane with potassium tert-butoxide.…”

“…If one looks for disilylated stibides, (R 3 Si) 2 SbM (M = Li, Na, K, and Mg), it becomes obvious that the only well-known example is (Me 3 Si) 2 SbLi, prepared first by Becker et al and known as solvates with either DME or THF. Reaction of (Me 3 Si) 3 Sb with MeLi provides convenient access to the stibide, which was shown to be extremely useful for the synthesis of a number of interesting compounds. − The analogous potassium stibide (Me 3 Si) 2 SbK was obtained by reaction of (Me 3 Si) 3 Sb with potassium tert -butoxide…”