Scandium complexes chlorides

Scandium complexes with chloride ion in aqueous solution, and there is ion-exchange evidence for anionic species, presumably ScClJ aq, in concentrated hydrochloric acid,119 while values of K = 90 and K2 - 37 for the first two association constants have been reported.1211 Solid salts of the anions ScClt-, St Cll- and ScCl2- have been isolated with alkali metal cations.121,122 It seems likely that both the first two species are octahedral and bridged-octahedral respectively, in line with Cs2NaScCl6 which has an X-ray powder pattern in accord with a face-centred cubic structure.123... 

For example, the treatment of the scandium complex 5 (L)ScR (R = —CH2CMc3 or — CH2SiMe3) with one equivalent of trimethylsilyl chloride (or iodide) resulted in the formation of intermediate 6 in which one NHC has been displaced and binds the TMS group. The compoimds slowly converted into the corresponding (L)ScX (X = C1 or I) complex 7 and the product of C—Si bond formation (Me3CCH2SiMe3 or Me3SiCH2SiMc3) [20]. 

The fact that the scandium(III) ion has the 3d electronic configuration severely limits the kinds of physical methods that can be brought to bear on determining the nature of the chemical environment in its complexes. The Sc nuclide has 100% natural abundance and a high sensitivity compared to protons and NMR studies using Sc may well prove to be a powerful tool (Melson et al., 1974). NMR spectra of aqueous solutions of scandium(III) chloride, perchlorate, nitrate, and sulfate have been obtained and it has been demonstrated that the chemical shifts for Sc at very low concentrations for the chloride, bromide, and perchlorate are independent of the anion and may be characteristic of the [Sc(OH)] ion. At higher concentrations the chemical shifts are both anion- and concentration-dependent and reflect the formation of bromo and chloro complexes and in the case of the perchlorate, polymeric hydroxo species. The chemical shifts for the nitrate and sulfate are different from the others and indicate that even at low concentrations there must be significant quantities of the respective complexes. 

Scandium is not an uncommon element, but is difficult to extract. The only oxidation state in its compounds is -I- 3, where it has formally lost the 3d 4s electrons, and it shows virtually no transition characteristics. In fact, its chemistry is very similar to that of aluminium (for example hydrous oxide SC2O3, amphoteric forms a complex [ScFg] chloride SCCI3 hydrolysed by water). 

Porphyrins, hydroporphyrins, azaporphyrins, phthalocyanines, corroles, corrins, and related macrocycles were discussed in CCC (1987).144 The octaethylporphyrin complexes of scandium were also previously mentioned in CCC (1987).1 The octaethylporphyrin (oep) scandium chloride complex (oep)ScCl, prepared by the reaction of the dilithium porphyrin with ScCl3(thf)3, has proved... 

Single crystal X-ray structures of CpDoCp HScCl and CpDoCp HScMe were published. Both molecules showed a similar structure. The Cl complex is one of the very few examples of a di(cyclopentadienyl)scandium chloride without bridging chlorine atoms. This terminal Sc-Cl distance is 2.4574(12) A shorter than in a scandium chloride complex with bridging chlorine atoms like [Cp"2Sc(/r-Cl)]2 with 2.58 A. The scandium metal atom is surrounded by four ligands in a distorted tetrahedral geometry. The coordinated dimethylamino group decreases the Lewis acidity... 

SCANDIUM TRICHLORIDE TRIS(TETRAHYDROFURAN) AND 0-DIKETIMINATE-SUPPORTED SCANDIUM CHLORIDE COMPLEXES... 

ScCI3, Scandium chloride, 22 39 ScCl3Cs, Cesium scandium chloride, 22 23 ScC1303C 2Hm, Scandium(lll), trichloro-tris(tetrahydrofuran)-, 21 139 Sc2CI,Cs3, Cesium scandium chloride, 22 25 SeC, Carbon selenide, chromium complex, 21 1, 2 Se2C, Carbon diselenide, 21 6, 7 Se2NC3H,i, Diselenocaibamic acid, N,N-di-ethyl-,... 

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