Scandium, tris structure

Scandium, tetrakis(tropolone)-stereochemistry, 1,94 Scandium, tris(acetylacetone)-structure, 1. 65, 68 Scandium, tris(tropolonate)-structure, 1,68 Scandium aryloxides spectroscopy, 2, 346 Scandium chloride... 

Structural analysis of several octahedral Sc(III) complexes have recently been reported. The structure 44) of anhydrous scandium-tris-acetylacetonate, Sc(acac)3, consists of discrete Sc(CH3COCHCOCH3)3 entity, with slight deviation from Dz symmetry. The coordination polyhedron around Sc (III) is a distorted... 

Analogous methyl compoimds are iU-characterized and appear to be polymeric [129). The air-sensitive phenyl derivatives when first obtained from THF are soluble in benzene, but when dried completely are no longer soluble — apparently due to pol5unerization. The homoaryl complexes of the smaller scandium, and yttrium ions form only the tris complexes Sc(CeH5)3 and Y(C6H5)3 [129) It is apparent that the structure and stabihty of the homoaryls are dependent on the metal ionic radii and the steric bulkiness of the phenyl group. 

Scandium metallofullerenes were also produced in macroscopic quantity and solvent-extracted by Shinohara et al. (1992b) and Yannoni et al. (1992). The Sc fullerenes exist in extracts as a variety of species (mono-, di-, tri-and even tetra-scandium fullerenes), typically as Sc Cs2/ Sc2 C74, Sc2 Cs2, Sc2 Cg4, Sc3 Cs2, and Sc4 C82- It was found that Scs C82 was also an ESR-active species whereas di-and tetra-scandium fullerenes like Sc2 C84 and Sc4 C82 were ESR-silent. (See Section 5 for the present correct assignment for some of the di- and tri-scandium metallofullerenes.) A detailed discussion on the electronic structures of the scandium fullerenes accrued from these ESR experiments is given in Section 6.1. 

Since the determination of the structure of tris(acetylacetonato)scandium (Sc—O of 2.061-2.082 A, average Sc—O 2.070(9) A), several other diketonates have been examined, though no detailed structures have been reported. The compound mer-[Sc(CF3COCHCOCH3)3] is isostruc-tural with the aluminium, gallium, rhodium, and iridium analogues, as well as those of the 3d metals V-Co whilst the dipivaloylmethanide [Sc(Me3COCHCOMe3)3] is isostructural with the iron and indium analogues. Scandium a-diketonates such as [Sc(tropolonate)3] form adducts in... 

Hitchcock, P. B., Lappert, M. P., and Singh, A., Three and four-co-ordinate hydrocarbon-soluble aryloxides of scandium, yttrium and the lanthanides X-ray crystal structure of tris(2,6-di-t-butyl-4-methylphenoxo)scandium, J. Chem. Soc. Chem. Commun., 1499 (1983). 

The first example of a group 3 NHC complex was reported by Arduengo et al. in 1994 with yttrium (Scheme 14.1) [12]. The seven-coordinate yttrium carbene complex 1 was obtained from the direct reaction of the free carbene 1,3-dimethyl-4,5-dimethylimidazol-2-ylidene with tris(2,2,6,6-tetramethylheptane-3,5-dionato)yttrium, Y(thd)3 and features a NMR doublet resonance for the carbene atom (d 199.4 ppm) with a coupling constant of 33 Hz to the nucleus. The first scandium NHC complexes were only recently described. Cui and coworkers prepared indenyl-functionaUzed NHC carbene scandium complex 2 in 2007 [13,14]. Complex 2 could be structurally characterized by X-ray... 

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