Yttrium organometallic compounds

Organometallic compounds of lanthanide metals other than Sm, Eu, and Yb are very rare until now. But the development of this chemistry became possible after the synthesis of divalent precursors of Tm, Dy, and Nd in the late 1990s, namely of their diiodides (see Scandium, Yttrium the Lanthanides Inorganic Coordination Chemistry) and by using hgands such as phospholyl or arsolyl, which stabilize divalent lanthanide ions. 

For organometallic compounds, the situation becomes even more complicated because the presence of elements such as platinum, iron, and copper introduces more complex isotopic patterns. In a very general sense, for inorganic chemistry, as atomic number increases, the number of isotopes occurring naturally for any one element can increase considerably. An element of small atomic number, lithium, has only two natural isotopes, but tin has ten, xenon has nine, and mercury has seven isotopes. This general phenomenon should be approached with caution because, for example, yttrium of atomic mass 89 is monoisotopic, and iridium has just two natural isotopes at masses 191 and 193. Nevertheless, the occurrence and variation in patterns of multi-isotopic elements often make their mass spectrometric identification easy, as depicted for the cases of dimethylmercury and dimethylplatinum in Figure 47.4. 

In this article the term organometallic compound includes alkyl and aryl derivatives of the rare earths—the transition metals of group III, scandium, yttrium, lanthanum and the lanthanides cerium to liitetium with covalent metal-to-carbon a-bonds, as well as the so-called 77-complexes with more than monohapto metal-to-carbon bonds, for example cyclopentadienyl and olefin complexes, metal acetylides, but not carbonyls, cyanides and isocyanide complexes. Derivatives of scandium, yttrium and lanthanum are included and discussed together with the compounds of the lanthanides, because of many similarities in the synthesis and the chemistry of these organometallic derivatives of the rare earths. 

Voskoboynikov, A.Z., Parshina, I.N., Shestakova, A.K. et al. (1997) Reactivity of lanthanide and yttrium hydrides and hydrocarbyls toward organosilicon hydrides and related compounds. Organometallics, 16, 4041. 

Con arable small jyc coupling constants around 20 Hz are typical for binuclear yttrium compounds with bridging alkyl groups. See for example C. J. Schaverien, Organometallics 1994,13, 69. 

Gmelin L, et al. (1980, 1988, 1990) Handbook of inorganic and organometallic chemistry. No 39, Cosmochemistry, Yttrium Borides, Coordination Compounds, Springer-Verlag, Berlin. 

Recently, groups experienced in Group IVB chemistry started research programs with the objective to study Group IIIB organometallic chemistry in relation both to early transition metals and f-elements. Thompson and Bercaw recently published their results on Cp ScR compounds [33]. Our work on Cp YR chemistry will be reported in the following section. In relation to this, relevant literature data on organo-yttrium chemisty will be mentioned first. 

In spite of the rather promising situation for Sc, NMR studies of this nucleus are quite scarce [37,141] in that, organometallic systems have hardly been considered. Some more studies of organo-yttrium compounds have, however, been carried out [30]. Thus, Evans et al. have undertaken the study of nine bis- and tris(cyclopentadi-... 

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