In:
Zeitschrift für Naturforschung B, Walter de Gruyter GmbH, Vol. 49, No. 2 ( 1994-2-1), p. 199-210
Abstract:
Bis[bis(trimethylsilyl)methyl]-as well as bis(2,2,4,4,6,6-hexa-methyl-2,4,6-trisila-cyclo-hexyl)zinc react with methyl lithium or phenyl lithium in the pres ence of the tridentate l,3,5-trimethyl-l,3,5-triazinane (TMTA) to yield zincates of the type LiZnR 2 R'·2TMTA. The compounds are colorless and insoluble in aliphatic or aromatic hydrocarbons. These zincates exist in solution as well as in the crystalline state as separated ions, as confirmed for lithium-methyl-bis(2,2,4,4,6,6-hexamethyl-2,4,6-trisila-cyc/o-hexyl)-zincate · 2TMTA by X-ray diffraction (P1̄; a -1139,5(3); b = 1482,4(4); c = 1528,6(5) pm; α = 95,33(2); β = 100,13(2); γ = 106,91(2)°; Z = 2). The lithium cation is six-coordinated by two TMTA ligands in a distorted anti-prismatic complex. The zinc atom displays a trigonal planar coordination with Zn-C bond lengths of 207 pm to the 2,2,4,4,6,6-hexamethyl-2,4,6-trisila-cyc/o-hexyl ligands and of 202 pm to the methyl group. One trisila-cyc/o-hexyl substi tuent exists in the chair, the other one in the twist conformation. The reaction of lithium bis(trimethylsilyl)amide with bis(trimethylsilylmethyl)zinc yields the benzene soluble lithium-bis(trimethylsilyl)amino-bis(trimethylsilylmethyl)zincate TMTA. The molecular structure was confirmed by X-ray diffraction (P2 1 2 1 2 1 ; a -1024,8(3); b = 1775,4(7), c = 1918,2(8) pm; Z = 4). The bridging bis(trimethylsilyl)amino ligand displays long Zn-N and Li-N distances of 213 and 208 pm, respectively, due to the steric inter-ligand repulsion. During the reaction of lithium bis(trimethylsilyl)amide with bis[bis(trimethylsilyl)methyl]-zinc no zincate formations observed. The decomposition products lithium bis(trimethylsilyl)-methanide and the heteroleptic bis(trimethylsilyl)amino-bis(trimethylsilyl)methylzinc were detected.
Type of Medium:
Online Resource
ISSN:
1865-7117
,
0932-0776
DOI:
10.1515/znb-1994-0208
Language:
English
Publisher:
Walter de Gruyter GmbH
Publication Date:
1994
detail.hit.zdb_id:
2078109-X
detail.hit.zdb_id:
124635-5
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