Poly[[μ-dioxane-κ²O:O′-dioxane-κO-μ-diphenylamido-κ²N:N-potassium] dioxane solvate]

Abstract

Key indicators: single-crystal X-ray study; T = 183 K; mean (C-C) = 0.003 Å; R factor = 0.044; wR factor = 0.107; data-to-parameter ratio = 18.9.

Synthesis and Crystal Structures of Lithium, Sodium, and ­Potassium Derivatives of 2‐(Methylthio)aniline and 2‐(Phenylthio)aniline

“…The 7 Li shifts are close to the value observed for LiClO 4 in THF (δ =0.60 ppm) [12] which indicates that compounds 1 and 2 exist in solution probably as contact ion pairs. Similar results are also obtained for the 23 Na NMR spectra of compounds 3 and 4, which exhibit singlet signals at δ = 8.1 and 6.1 ppm, respectively. This shift range is typical for [Na(THF) n ] + cations which display shifts around 7.1 ppm.…”

“…Comparable distances have been observed for [K(NPh 2 )(diox) 1.5 ] (K-N: 279.0-290.2 pm), [23] [K(NPh 2 )(THF) 3 ] (K-N: 279.5(2)-285.6(2) pm), [24] and [K(NPhiPr)(DME) 2 ] (284.8(2)-289.8(2) pm). [18] It is worthy to note that the dissimilarities of the K-N distances in compounds 5 and 6·DME are much more pronounced than in the reference compounds.…”

Electronic, Steric, and Ligand Influence on the Solid‐State Structures of Substituted Sodium and Potassium Anilides

“…[1,2,18] The use of heavier alkali metals often leads to increased reactivity, enhanced ionicity of the A-N bond, and enhanced salt-like behavior, which includes poor solubility in common organic solvents. Despite the extensive use of potassium anilides in metathesis reactions, structural characterization is limited to a few examples, namely, [(diox)KNPh 2 ] ϱ , [19] [(thf) 3 KNPh 2 ] 2 , [20] [(tmeda) 1.5 KNPh 2 ] ϱ , [21] and the separated ion pair [(18C6K)(NPh 2 )] (18C6 = 18-crown-6). [22] More interest was paid to the bis(trimethylsilyl)amides of the heavier alkali metals, because the bulky N(SiMe 3 ) 2 ion ensures the formation of smaller aggregates and provides steric protection of the A-N bond, which lead to enhanced solubility and reduced sensitivity towards moisture and air and simplified preparation, handling, and manipulation.…”

Structural Elucidation of tmeda‐Solvated Alkali Metal Diphenylamide Complexes

“…It consists of a planar K 2 N 2 ring (sum of endocyclic angles: 360°); however, due to the larger size of potassium, its coordination sphere can accommodate an additional donor atom (hence each K atom is five-coordinate). Supplementary stabilisation by K···π-arene interactions appears minimal [shortest K···C separations are 3.1936 (13) Only three other donor complexes of potassium diphenylamide have been crystallographically characterised, namely the solvent-separated 18-crown-6, [82] dimeric thf [61] and polymeric dioxane [62] solvates ( Figure 6). Clear structural similarities exist between 3 and the aforementioned Figure 6.…”

“…[36,[49][50][51][52][53][54] Turning to homometallic species, lithium diphenylamide has been shown to form co-complexes with: (i) lithium chloride; [55] (ii) n-butyllithium and mono-ortho-metallated LiNPh 2 ; [56] and (iii) dilithium diphenylhydrazide. [57] But perhaps most pertinent to this study, several alkali metal diphenylamides stabilised by donor ligands (e.g., various ethers [58][59][60][61][62] and pyridine [58] ) have been reported. However, prior to this report surprisingly no homometallic sodium diphenylamide complexes have been reported thus far.…”