Mono complexes lanthanides

Radonovich and Click [156) in 1971 reported the crystal structure of Pr(terp)Cl3 8H2O complex, which they prepared by the original method of Sinha [157), for the preparation of mono-terpyridyl-lanthanide(III) chlorides, [M(terp)Cl3 wHaO], where terp =2,2, 2"-terpyridyl and has the following structure. When... 

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... 

Mono(organo)nickel compounds, via oxidative addition, 8, 44 Monoorganotin hydroxides, preparation, 3, 850 Monoorganotin oxides, preparation, 3, 850 Mono(pentamethylcyclopentadienyl) actinide(IV) compounds, reactions, 4, 207 Mono(pentamethylcyclopentadienyl) lanthanide(III) compounds, synthesis and characteristics, 4, 66 Mono(pentamethylcyclopentadienyl) uranium(IV) sulfido complex, synthesis, 4, 207-208 Mono(phenoxy-aldehyde) trichlorides, with Zr(IV),... 

Dipicolinates (pyridine-2,6-dicarboxylates) have been investigated in some detail with structures determined for several tris complexes such as Na3[Nd(dipic)3]-15H20 and Na3[Yb(dipic)3]13H20, typical of the early and later lanthanides, respectively. The lanthanides have essentially tricapped trigonal prismatic coordination geometries, isostruc-tural along the lanthanide series they have been the subject of important solution NMR studies. Mono and bis complexes can also be synthesized the mono complex [Nd(dipic)(H20)4] CIO4 has a polymeric structure in which each picolinate is bound to three different (nine-coordinate) neodymium ions. 

Polydentate nitrogen ligands are very suited to stabilize mono(cyclooctatetraene) lanthanide(III) complexes. These include silylated benzamidinates [RC6H4C(NSiMe3)2]Ln-(COT)(THF) (Ln = Y, Ce, Pr, Nd, Sm, Tm, Lu R = H, MeO, CF3) (Figure 82a) and diiminophosphinates... 

Mono(cyclopentadienyl)lanthanide diiodides are readily accessible utilizing the very bulky l,2,4-tris(trimethyl-silyl)cyclopentadienyl ligand (= Cp ")- A typical example is depicted in Scheme 50.252 Cp" LaI2(THF)3 also served as a useful starting material for the preparation of a series of mono(cyclopentadienyl)lanthanum-anilido complexes.2... 

Pendant-arm amido-cyclopentadienyl ligands have also been shown to be useful in the stabilization of highly reactive mono(cyclopentadienyl)lanthanide alkyl and hydrido complexes. When the tris(trimethylsilylmethyl) complexes of lutetium and ytterbium, Ln(CFI2SiMe3)3(TFIF)2, were treated in pentane solution with 1 equiv. of (CsMe4H)SiMe2NHCMe2R (R = Me, Et) at 0°C, the new complexes (rfir)1-... 

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... 

Also the salt-free and solvent-free mono Cp lanthanide alkyl complex Cp La[CH-(SiMe3)2]2 has been synthesized and the X-ray structure together with that of its THF precursor show the stabilization of the unsaturated lanthanum center by unusual agostic Si-C bonds. The removal of THF produces a different conformation of the disylil ligands and pyramidalization of the Cp La [CH(SiMe3)2]2 moiety. 

Different main-group-, transition- and lanthanide-metal complexes can catalyze the cycloaddition reaction of activated aldehydes with activated and non-activated dienes. The chiral metal complexes which can catalyze these reactions include complexes which enable substrates to coordinate in a mono- or bidentate fashion. 

In a systematic study, it was demonstrated that, using a specially designed bulky benzamidinate ligand, it is possible to isolate mono(amidinato) dialkyl complexes over the full size range of the Group 3 and lanthanide metals, i.e., from scandium to lanthanum. The synthetic methods leading to the neutral and cationic bis(alkyls) are summarized in Scheme 56. Figure 18 displays the molecular structures of the cations obtained with Sc, Gd, and La. ... 

Although direct reaction of lanthanide mono-porphyrins with free phthalo-cyanine or its lithium derivatives is generally more efficient than the template synthesis, and gives rise to mixed-ligand complexes, the template strategy can also be applied for synthesis of phthalocyanine-porphyrin complexes, as in the case of unsymmetric bisphthalocyanine complexes (Scheme 8.2, B(b)) [106, 136, 145, 146]. Thus, metallation of free porphyrins with lanthanide salts in TCB or n-octanol leads to single-decker complexes, which then react with phthalonitriles under the action of DBU in alcoholic media to give the desired compounds. 

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