Über Metallalkyl‐ und ‐aryl‐Verbindungen, XXX. Darstellung und Kristallstruktur von Bis[μ‐phenylethinyl‐( N , N , N ′, N ′‐tetramethyl‐1,3‐propandiamin) lithium], (PhCCLi·tmpda) ₂ , eine dimere Verbindung mit Phenylethinyl‐Brücken

Abstract

The title compound has been prepared from n-butyllithium, phenylacetylene and N,N,N>N'-tetramethyl-l,3-propanediamine (tmpda) and its structure determined by X-ray diffraction methods. It represents a first example containing phenylethynyl bridges between alkali metal atoms and is isostructural to the phenyl compounds (PhLi . tmeda),.In einer friiheren Arbeit') haben wir am Beispiel (PhCZ C),Mg(tmeda), die Struktur einer ersten Magnesium-Alkinyl-Verbindung beschrieben. Sie enthalt sechsfach koordiniertes Magnesium mit trans-standigen Phenylethinyl-Liganden.In

Organometallic Compounds of the Alkali Metals with Phenylsilyl Substituents at the Carbanionic Center. Crystal Structures of LiC(SiMe3)2(SiMe2Ph)·Et2O, NaC(SiMe3)2(SiMe2Ph)·TMEDA, NaC(SiMe3)(SiMe2Ph)2·TMEDA, {LiCH(SiMe2Ph)2}2, RbC(SiMe2Ph)3, and CsC(SiMe2Ph)3 (TMEDA = Tetramethylethylenediamine)

“…The Li 2 C 2 ring is almost planar (sum of angles 358.1°) and slightly unsymmetrical. The average Li−C bond lengths (2.155 and 2.220 Å) are similar to those in 1a (2.291(6) and 2.303(6) Å) 2 and in complexes such as LiC 4 H 5 ·TMEDA, C 4 H 5 = bicyclo[1.1.0]buta-1-yl (2.23(5) Å),27a {Li t Bu(OEt 2 )} 2 (2.184(6) Å),27b (LiPh·TMEDA) 2 (2.208(6), 2.278(6)Å),27c (LiCH 2 SMe·TMEDA) 2 (2.240(7) Å),27d and (Li(C⋮CPh)TMPA) 2 , TMPA = tetramethyl-1,3-propanediamine (2.148(7) Å) 27e. The Si−C, Si−Me, and C−C bond lengths are normal, the C1(or C18)−Si−C angles wide, and the Me−C−Me and Me−C−Ph angles compressed.…”

Synthesis and Characterization of Alkynyl Complexes of Groups 1 and 2

“…[4] Frequently, these tetramers are coordinated by chelating nitrogen donor bases and/or further associated to [Li 4 C 4 ] 1 coordination polymers. For example, the dimeric compounds [PhC CLi·tmpda] 2 (1) [5] (tmpda = N,N,N,Ntetramethyl-1,3-propanediamine) and [(PhC CLi) 4 A C H T U N G T R E N N U N G (tmhda) 2 ] (2) [6] (tmhda = N,N,N,N-tetramethyl-1,6-hexanediamine) with a tetrahedral arrangement of the four lithium atoms are structurally characterized. Dimers as well as tetramers of RC CLi were detected in THF solutions.…”

Alkali Metal Cation π-Interactions in Metalated and Nonmetalated Acetylenes: π-Bonded Lithiums in the X-ray Crystal Structures of [Li−C⋮C−SiMe2−C6H4−OMe]6and [Li−O−CMe2−C⋮C−H]6and Computational Studies

“…However, such metal π-contacts are not always significant; e.g., note the large M−C β separations (>3 Å) in the oligomeric lithium acetylides: [(t-Bu−C⋮C−Li) 4 (THF) 4 ] ( 3 ), [(t-Bu− C⋮C−Li) 12 (THF) 4 ], [(Ph−C⋮C−Li)tmpda] 2 ( 4 ), and [(Ph−C⋮C−Li) 4 (tmhda) 4/2 ] ( 5 ) 9 (Table ). In contrast, the short Be−C β distances indicate π-interactions in [(Me−C⋮C) 2 BeNMe 3 ] 2 ( 6 ) (Table ) …”