Group 1 Complexes of an (Amido-amino)silane and Their Use in the Synthesis of the Bi(III) Amide, Bi(Me₂Si{NAr}{N(H)Ar})Cl₂ (Ar = 2,6-i-Pr₂C₆H₃)

Abstract

The synthesis of sodium and potassium salts of the monoanionic, (amido-amino)silane, [Me 2 Si{NAr}{N(H)-Ar}] − (Ar = 2,6-i-Pr 2 C 6 H 3 ), and their use as ligand transfer reagents to bismuth are presented. Initial attempts to form Li(Me 2 Si{NAr}{N(H)Ar) (2) using equimolar amounts of n-BuLi and the neutral compound Me 2 Si{N(H)Ar} 2 (1) gave mixtures of the unreacted di(amino)silane and the known dianion, Li 2 (Me 2 Si{NAr} 2 ), on workup. Reaction of 1 with NaH and KH, however, afforded the desired anion in the soluble, crystalline compounds Na(Me 2 Si{NAr}{N(H)Ar})-(THF) 3 (3(THF) 3 ) and K(Me 2 Si{NAr}{N(H)Ar}) (4). The crystal structure of 4 shows a cyclic hexamer [4] 6 , containing intra-and intermolecular K•••π-aryl interactions. Reaction of 3 or 4 with BiCl 3 demonstrated that both compounds are effective ligand transfer reagents, affording the bismuth compound Bi(Me 2 Si{NAr}{N(H)Ar})Cl 2 (5). The crystal structure of 5 showed a primary monodentate κ 1 -N-bonding mode for the ligand with a close Bi•••N contact to the neutral amino nitrogen atom. Long range Bi•••Cl interactions associate these molecules into dimers, [5] 2 .

Exploiting Deprotonative Co‐complexation to Access Potassium Metal(ates) Supported by a Bulky Silyl(bis)amide Ligand

“…This polymeric arrangement contrasts with the molecular hexameric motif reported by Coles for related potassium silyl(amide)amine complex [{Me 2 Si(NHAr*)(NAr*)K} 6 ], [11] which can be attributed to the lack of aromatic substituents on silicon to enable propagation. Thus, in this case potassium forms π‐interactions with the aromatic ring of the NHAr* group and with the NAr* ring of a neighbouring unit, giving rise to a cyclic hexameric structure.…”

Structural Diversity in Alkali Metal and Alkali Metal Magnesiate Chemistry of the Bulky 2,6‐Diisopropyl‐N‐(trimethylsilyl)anilino Ligand

“…K2 occupies a highly distorted tetrahedral N 4 site [bond angles ranging from 66.72(9)° to 148.95(9)°, with the extremities representing the TMEDA bite angle and amido‐K‐amido angle, respectively] comprising the two TMEDA N atoms and two anionic N atoms, belonging to two amide ligands (range of bond lengths, 2.780(3) to 2.830(3) Å). In contrast, K1 lies between the aryl rings of two transoid disposed Dipp ligands, in a near linear sandwich arrangement (centroid‐K‐centroid angle, 165.8°; mean K−C(centroid) length, 2.7926 Å) architecturally akin to classic structures such as bis(benzene)chromium, though the bonding in potassium sandwiches is electrostatic in origin . Formally this [(K) + (R 2 K⋅TMEDA) − ] formulation of 8 in which K1 does not engage with an anionic centre (discounting any delocalisation within the Dipp aryl ring) can be described as a potassium potassiate.…”

Exploring the solid state and solution structural chemistry of the utility amide potassium hexamethyldisilazide (KHMDS)

“…Both compounds, 10 and 11, crystallise from toluene solutions. The affinity of heavy alkali metals to engage π-interactions with arenes is well known; 42,[80][81][82][83][84][85][86] however, in the presence of the corresponding multidentate ligands TMDAE and TMEEA in 10 and 11, respectively, there is no interaction with the arene in the solid-state structures.…”