Some sterically hindered lithium alkylbromo- and alkylchloro-magnesates, -cadmates, and -manganates. Crystal and molecular structures of [Li(thf)₂(µ-Br)₂Mg{C(SiMe₃)₃}(thf)], [Li(thf)₄][{Cd[C(SiMe₃)₃]}₃(µ-Br)₃(µ₃-Br)]·0.5C₆H₁₂, [{Li(thf)}₃(µ₃-Br)₃(µ₃-OSiMe₃)Cd{C(SiMe₃)₃}], and [Li(thf)₄][{Mn

Abstract

ChemInform Abstract The Li compound (I) reacts with (II) to give the magnesate (IV) (no yield given) which is the first one of this type to be characterized by a crystal structure determination ( P21/n, Z=4). The reaction with CdBr2 (V) gives a compound (VI) with a cage anion crystallizing in P3 with Z=2. In the presence of traces of moisture, the neutral compound (VII) (Pnam, Z=4) is isolated. (VI) and (VII) can be converted into (VIII) on heating. The chloride compound (XII), obtained on heating from (XI), is dimeric in the gas phase. The cadmate (XIV) can be converted into (XV) and (XVII) ((XVIIa) obtained at reflux temp., (XVIIb) at 20 rc C). The trimanganate (XVIII), described previously, is characterized by an X-ray diffraction study (P21/m, Z=2). The different types of structure are discussed. In each C(SiMe3)3 group the three silyl fragments are twisted from fully staggered positions so the group as a whole is chiral.

An alkylzinc bromide and a lithium alkyldibromozincate containing tris(organosilyl)methyl groups

“…We reported previously that the lithium organocadmates Li(THF)CdX 2 C(SiMe 3 ) 3 (X ¼ Cl or Br), obtained from the reaction between LiC(SiMe 3 ) 3 and the halides CdX 2 , decomposed on heating to give lithium halides and organocadmiun halides [16]. No similar reaction was detected when the zincate 4 was heated under reflux in either hexane or THF.…”

“…The zinc is only threecoordinate, as in [(PhMe 2 Si) 3 CZnCl)] 2 [4], and the bonds to bromine and carbon are almost coplanar (sum of angles at Zn 357°). The structure may be compared with that of the magnesate 8, in which there is an additional molecule of THF attached to the metal centre [16]. The THF is absent in 4, probably because the NMePh group is larger than Me and zinc is both smaller and less acidic than magnesium.…”

Mixed Lithium Complexes: Structure and Applicationin Synthesis

“…All three (44)(45)(46) contain the bromide ion and were synthesized by Eaborn and Smith and coworkers. They are all monomeric bimetallic complexes with the same general formula [(donor A) x Li(μ-Br) 2 Mg(alkyl)(donor B) y ] ( Figure 5.12) [49,50].…”

“…12 Structural representations of three X-ray-characterized pre-''turbo-Grignard''-type reagents[49,50].…”

Synthesis and crystal structures of some cobalt halide derivatives containing alkyl or silanolato groups

“…3). A trimethylsilanolato derivative 7 was obtained about 20 years ago from CdBr 2 and (Me 3 Si) 3 -CLi [12].…”