Lanthanide cyclooctatetraenyl complexes

Mono(cyclooctatetraenyl) lanthanide(III) compounds, synthesis and characteristics, 4, 124 Mono(cyclooctatetraenyl) zirconium(III) compounds, preparation and reactions, 4, 743 Mono(cyclopentadienyl) amido complexes alkane elimination, 4, 446 amine elimination, 4, 442 HCL elimination, 4, 446 metathesis reactions, 4, 438 miscellaneous reactions, 4, 448 properties, 4, 437... 

A recent development in this field involves the combination of benzamidi-nate ligands with cyclopentadienyl or cyclooctatetraenyl ligands in the coordination sphere of lanthanide ions. The first lanthanide complexes containing both benzamidinate and pentamethylcyclopentadienyl bonded to yttrium was reported by Teuben et al. Yttrium aryloxides as well as anhydrous yttrium trichloride can be used as starting materials in these preparations (Eq. 19, Scheme 5) [27] ... 

More recently several lanthanide diiminophosphinate derivatives containing additional i/8-cyclooctatetraenyl ligands have been prepared and characterized. The complexes [Ph2P(NSiMe3)2](C8H8)Ln(THF) (58) were obtained according to Eq. (22) and isolated as air-sensitive, crystalline solids in 77-84% yield [71] ... 

Cyclooctatetraenyl lanthanide(III) halides of the type [(COT)Ln(/x-Cl)(THF)2]2 (Figure 77a) are the most important precursors for the preparation of other half-sandwich (see Half-sandwich Complexes) and mixed sandwich complexes with cyclooctatetraenyl ligands. These complexes are readily accessible by reacting anhydrons lanthanide trichlorides with K2[C0T] in a molar ratio of 1 1. The compounds consist of centrosyimnetric, chloro-bridged dimers with... 

The synthesis, structure, and physical and chemical properties of organo-lanthanide complexes containing only polyhaptocyclopentadienyl and cyclooctatetraenyl metal-carbon bonds are fully covered in other reviews (5-7). This section will focus on lanthanide-carbon single bonded species only. Ln—C single bonds are found almost exclusively in only two types of complexes homoleptic complexes, and heteroleptic... 

Following the synthesis of tris(cyclopentadienyl) lanthanide complexes, the first examples of organolanthanide derivatives, a vast number of organolanthanide it-complexes with cyclopen-tadienyl (Cp), indenyl (Ind), cyclooctatetraenyl (COT), and related substituted derivatives have been prepared and extensively reviewed [3]. Here we will briefly discuss cyclopentadienyl and allyl derivatives as representatives of organolanthanide K-complexes. 

The dimeric mono(cyclooctatetraenyl)lanthanide chlorides [(COT)Ln(/r-Cl)(THF)2]2 are long known and still represent the most useful precursors in (COT)Ln chemistry. A recently reported alternative preparation of the Sm derivative involves the reaction of samarium metal with COT in THF in the presence of a small amount of I IgCL. The molecular structure of [(COT)Sm(/i-CI)(TT 11 )2]2 has been determined.805,806 Iodo-(cyclooctatetraenyl)lanthanide iodides of the type (COT)Lnl(TIIF) (Ln = La, Ce, Pr, n = 3 Ln = Nd, n = 2 Ln = Sm, n l) are readily accessible in a one-pot reaction of metallic lanthanides with COT in the presence of an equimolar amount of iodine. Bromo- and chloro-bridged binuclear complexes of samarium, [(COT)Sm(/.t-X)(THF )2]2 (X = Br, Cl), were also prepared by the reaction of samarium metal with COT in the presence of 1,2-dibromoethane or Ph3PCl2, respectively.807 Alternatively, the iodo complexes (COT)LnI(THF)3 (Ln = Nd, Sm) can be synthesized directly from the lanthanide triiodides and K2COT. The molecular structure of (COT)Ndl(THF)3 has been determined by X-ray diffraction.808 A clean preparation of the monomeric half-sandwich complex (GOT)TmI(THF)2 involves treatment of Tml2 with equimolar amounts of COT in THF at room temperature (Scheme 227). The product was isolated as red crystals in 75% yield.628... 

Although the elements of the lanthanide and actinide series have long been known to exhibit a quite extensive organometallic chemistry, it is only within the last decade that typical sandwich species have been prepared and studied. These systems however, although resembling the familiar metallocene and bis-arene compounds of the d-block elements, are not strictly their analogues since in both f-orbital series the known sandwich complexes are derived only from the cyclooctatetraenyl dianion. 

Main Group, Lanthanides and Actinides - In the series of papers Studies on Organolanthanide Complexes several topics have been covered the formation of ion-pair complexes of the type [ Na.phenan3 Cp]LnCl phenan] (phenan = 1,10-phenanthroline), the synthesis and structural chemistry of bismethoxylethylcyclopentadienyl complexes, and furan bridged bis-cyclopentadienyl complexes. A number of synthetic papers have also appeared in the area the synthesis of cyclooctatetraenyl-cyclopentadienyl sandwich complexes, " " the... 

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