In this paper, we present complementary series of crystal structures of lithium salts containing 4,5-dicyanoimidazolato anions substituted with perfluoroalkyl groups. Singlecrystal X-ray analysis of ten adducts with aprotic solvents: glymes -dimethyl ethers of poly(ethylene glycols) -and crown ethers have been performed to correlate their molecular structures and properties with spectroscopic and thermal data. Comprehensive structure analysis of crystalline materials reveals valuable information about coordination ability of substituted 4,5-dicyanoimidazolato anions and provides the basis to develop the model of poly(ethylene oxide) electrolytes and liquid systems. Presented results reveal new aggregation modes at high concentrations of lithium salts involving releasing cations by self-assembly of anionic subnetwork and shed some light on electrochemical performance of TDI anions.
The reaction of N-heterocyclic carbene (NHC) with dimeric dialkylgallium alkoxides, acting as nonselective or heteroselective catalysts in the polymerization of rac-LA, leads to highly active and isoselective monomeric Me(2)Ga(NHC)OR catalysts, resulting for the first time in the facile switch of stereoselectivity.
The reaction of MMe3 with 1 molar equiv of N-phenylsalicylideneimine (HsaldPh) yields
the O,N-chelate complexes Me2M(saldPh) (where M = Al (1), Ga (2), In (3)) in high yields.
The reaction of 1 with γ-picoline results in a ligand redistribution reaction and the formation
of the five-coordinate complex MeAl(saldPh)2 (4), while the gallium and indium compounds
are stable in the presence of γ-picoline. The resulting compounds have been characterized
in a solution by NMR and IR spectroscopy and cryoscopic molecular weight measurements,
and their molecular and crystal structure have been determined by X-ray crystallography.
Compounds 1 and 2 exist as monomeric tetrahedral complexes, while the indium analogue
3 is dimeric with the In2(μ-O)2 bridges and five-coordinate metal centers. The five-coordinate
methylaluminum compound 4 exhibits trigonal-bipyramidal geometry of the metal center.
The obtained results show that a Schiff base acts as a strongly coordinating chelate ligand
and, in this regard, it resembles the symmetrical acetylacetonato ligand and related
β-diketonates. An extended crystal structure analysis reveals that the isostructural crystalline
complexes 1 and 2 comprise monomeric four-coordinate molecules linked by C−Himino···O
hydrogen bonds, forming helical chains. Parallel left- and right-handed helices joined by
C−H···π interactions give rise to the 3D extended tetragonal framework, with voids filled
by solvent molecules. In the crystalline complex 4 the C−Haryl···O hydrogen bonds organize
molecules into H-bonded dimers.
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