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.

OR or OOR? The oxygenation of ZntBu2 in the presence of donor ligands demonstrates the tendency of zinc dialkyls to undergo oxidation of only one ZnC bond under controlled conditions (see scheme). The formation of alkoxide or peroxide species is influenced by the type of donor ligand employed, and these divergent pathways offer a glimpse into the general mechanism of dioxygen activation.

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.

Crystal structure of arsenolite, the cubic polymorph of arsenic(III) oxide, has been determined by single crystal X-ray diffraction up to 30 GPa. The bulk of the crystal is monotonically compressed with no detectable anomalies, to 60% of the initial volume at 30 GPa. In the structure the most compressed are As•••As contacts which contrasts with increased intramolecular As•••As distance in the deformed molecule. The ratio between As•••As inter-and intramolecular distances decreases from 1.47 at 0.1 MPa to 1.03 at 30 GPa. The As4O6 molecules are deformed to become more tetrahedron-like. Pressure above 3 GPa favours the formation of As4O6•2He inclusion compound in the surface layer increasingly deeper with pressure. The experimental As4O6 crystal compression has been compared with various theoretical models within the DFT framework. According to band-structure calculations the arsenolite band gap falls from 4.2 eV at ambient pressure to 2.7 eV at 27.8 GPa.

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Structural studies of the homoleptic main group metal alkyls are of fundamental interest to rationalize their physical behavior and reactivity, and they provide novel supramolecular structures with remarkable topologies and often unusual metal-ligand interactions. For instance, the structure of heavier group 13 trimethyls is topologically equivalent to the well-known zeolite type structures, 1 and the structure characterization of Mg t Bu 2 (i.e., the simplest dialkylmagnesium compound to be structurally authenticated) revealed that intra-and intermolecular CH 3 ‚‚‚Mg agostic interactions play a substantial role in the molecular assembly. 2 As noted by Seyferth in the seminal paper on the history of zinc alkyls chemistry, in recent years, there has been a renaissance in dialkylzinc chemistry due to the utility of this family of compounds in important synthetic processes. 3 Up to now, however, the structurally authenticated homoleptic dialkylzincs consist of sterically strongly encumbered methylsilyl ligands, 4 though some of lower zinc alkyls were investigated by a host of techniques 5 including molecular weight determination, NMR and IR spectroscopy, gas electron diffraction, and photoelectron spectroscopy. 6 Other structurally known examples are restricted to a very recently reported divinylzinc compound 7 and some diarylzinc compounds, including the unique structure of diphenylzinc, in which the monomeric ZnPh 2 units are associated into unsymmetrical dimers that are linked by further weaker interactions into tetrameric units. 8 Moreover, systematic investigations on the structure and relative stability of the ZnR 2 (L) n adduct as a function of the character of both the R substituent and L ligand are also relatively sparse. For instance, to our knowledge, of the Lewis acid-base adducts involving Zn t Bu 2 , only the threecoordinate ZnR 2 (L) complexes with the iminato ligand have been structurally authenticated. 9,10 On the other hand, during the past decade, the controlled selfassembly of metal-ligand complexes has attracted great attention owing to their wide potential applications as functional materials, and many supramolecular compounds with intriguing structures have been synthesized and characterized, such as the 1D chains, 2D layers, and 3D open frameworks. 11 In regard to 2D metalorganic frameworks, where honeycomb, brick wall, grid, square, or rectangular networks are known, nanofabrics still await their realization (Chart 1). 12 We report here a system involving Zn t Bu 2 and bipyridine ligands that brings together the major features mentioned above: the molecular structure of homoleptic metal alkyl and self-assembly of a metal-ligand complex leading to unprecedented topology of the 2D framework based on coordination polymers sustained by organometallic nodes.The limited experimental structural data for tert-butylzinc derivatives stimulated our interest in Zn t Bu 2 (1) and its adducts with pyridine ligands. The homoleptic starting compound 1 was prepared in high yield according to the literature ...

The prepared in situ methyl(chloro)aluminum complex (2) from Me2AlCl and the pendant arm tridentate Schiff base (H-SchNMe2) was used to generate the methylaluminum cationic species [(SchNMe2)AlMe]+ in further reaction with 1 equiv of AlCl3 or NaBPh4 as the chloride abstracting reagents. The exposure of the resulting methylaluminum cationic species to an excess of dry dioxygen at 0 degrees C afforded the alkoxyaluminum cationic species, [(SchNMe2)AlOMe]+ or [(SchNMe2)AlOPh]+. The alkoxylaluminum cations proved to be a very efficient catalyst in the polymerization of epsilon-caprolactone.