Silicone grease as a precursor to a pseudo crown ether ligand: crystal structure of [K⁺]₃[K(Me₂SiO)₇⁺][InH(CH₂CMe₃)₃^–]₄

Abstract

The crystallization of K [ I ~I H ( C H ~C M ~~) ~]from heptane in the presence of silicone grease led to the formation of the title compound, in which one potassium cation is surrounded by a planar ~yclo-(Me~SiO)~ ligand; K+...O distances range from 2.86(3) to 2.99(4) A.We have previously reported the preparation of K+ [InH( CH2CMe3)3-] along with a crystallographic study of the related dinuclear species K+[H{ In(CH2CMe3)3}2-]. * Attempts to crystallize K+[InH(CH2CMe3)3-] from pentane at low temperature produced large, colourless, transparent, rectangular crystals in the mother liquor. When the pentane was removed. the crystals became opaque and shattered. In an attempt to protect the material from solvent loss, the following crystallization procedure was used. A sample of K + [ I I I H ( C H ~C M ~~) ~-] and a small amount of Dow Corning high-vacuum silicone grease (intended to protect any crystals thus grown) were placed in a tube equipped with a Solv-Seal joint. Heptane was added by vacuum distillation. The solid dissolved as the mixture was warmed from -196 "C to room temp. over 2 h. Needle shaped single crystals formed overnight. The crystal used for the X-ray crystallographic study was cut from a larger crystal and mounted in a thin-walled capillary tube. [ N . B. All materials were handled under purified argon or in vacuo. Organoindium hydrides are

Synthesis and Coordination of the Cagelike Siloxane Compounds E2{(SiMe2)2O}3 (E = As, Sb, Bi)

“…Furthermore, no such dimerization was observed with the sodium salt of the weakly coordinating anion Na[Al(OR F ) 4 ]. However, the adduct [Na{Al(OR F ) 4 }] 2 [As 2 -{(SiMe 2 ) 2 O} 3 ] (12) was isolated ( Figure 7). This compound can be considered to be another example in which the cage compound 4 coordinates to a metal atom on the outside.…”

“…Compound 2 can host a lithium cation within the cage structure, whereas 1 showed the formation of the complex [Li@P 4 {(SiMe 2 ) 2 O} 6 ] + with the dimeric ligand P 4 {(SiMe 2 ) 2 This class of compounds can be considered as inorganic equivalents of the organic cryptands as Ritch and Chivers mentioned.…”

“…The first cyclosiloxane complex was reported by Churchill et 4 . [2] In 2006, Passmore et al obtained cyclosiloxane complexes directly by the reaction of alkali-metal ions with the cyclodimethylsiloxane (Me 2 SiO) n (n = 5, 6) when using a salt of a weakly coordinating anion. [3] To date, only a few complexes of siloxanes and siloxane derivatives are known.…”

Crystal structure of hexakis(dimethyl-μ-oxosilane)dibromozirconium(IV) bis(nonabromodizirconate(IV)), [Zr{(CH3)2SiO}6Br2][Zr2Br9]2

“…The compound wasprepared asabyproductfrom the bromination of Zr(C 5 H 5 ) 2 Br 2 in the presence of silicone grease [1,2], which in other cases canleadto[(CH 3 ) 2 SiO] 7 [3,4] and other related ligand systems [ 5]. Single crystals were formed directly from the unstirred reaction mixture over aperiod of two days.…”

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Source of materialThe compound wasprepared asabyproductfrom the bromination of Zr(C 5 H 5 ) 2 Br 2 in the presence of silicone grease [1,2], which in other cases canleadto[(CH 3 ) 2 SiO] 7 [3,4] and other related ligand systems [ 5]. Single crystals were formed directly from the unstirred reaction mixture over aperiod of two days.

Discussion

The titlecompound exists asasalt,with the dication possessing crystallographically imposed inversion symmetry, and being comprised of a trans-ZrBr 2 unit with equatorialcoordination arising from the oxygen atoms of a[Me 2 SiO] 6 ring.

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