Peter Poremba

Cyclooctatetraenyl complexes of the early transition metals and lanthanides: X. The first organometallic triple decker sandwich complexes of the lanthanides

Abstract Treatment of anhydrous lanthanide trichlorides with Li 2 C 8 H 6 (SiMe 3 ) 2 -1,4 in a 2:3 molar ratio affords the first well-defined organolanthanide triple decker sandwich complexes. The compounds Ln 2 [C 8 H 6 (SiMe 3 ) 2 -1,4] 3 ( 2 – 4 ; Ln=Ce, Nd, Sm) were characterized by elemental analyses and spectroscopic methods. An alternative preparation of 2 involves a ligand redistribution reaction between CeCl 3 and the anionic sandwich complex [Li(THF) 4 ][Ce{C 8 H 6 (SiMe 3 ) 2 -1,4} 2 ] ( 5 ).

Cyclooctatetraenyl complexes of the early transition metals and lanthanides VIII. Anionic sandwich complexes of the lanthanides containing silylated cyclooctatraenyl ligands

The new nniunic snndwich complcxea Il,i(l’l,iF),)[Ln(COT ‘ I21 (l-5. Ln = Ce. Pr, Nd, Sm. Y) have been prepared by treatment of anhydrous lauthunidr trichloridea with two cyuivulrnts of Li,COT * [COT * = C,H,WMe,~~-l,4]. Ion exchongc of 4 with [PPNjCI affords the derivative (PPN~SnICU’I’ ’ i, j W. Similurly. the hexuhilyiuted sandwich salt [K(THF),~Tb(COT * ’ h] (7) [COT’ * * = CHll S(SiMr,,),- I .3.6] has bcn ohtt\incd by reucting unhydmus TbCl 3 with K ,COT * ’ in B I:2 molar ratio. The molecular sfructure of 4 has hecn dctcrmincd hy X-my Jiffruulion. 0 IO97 Elscvicr Science S.A.

Cyclooctatetraenyl complexes of the early transition metals and lanthanides: Part XII. New sandwich and half-sandwich complexes of the lanthanides containing cyclooctatetraenyl ligands

Abstract The crystal structure of [(COT)Ce(μ-O 3 SCF 3 )(THF) 2 ] 2 ( 1 ) (COT=η 8 -C 8 H 8 ) has been determined by X-ray diffraction. The compound crystallizes in the triclinic space group P 1 ( a =930.7(4), b =1274.4(7), c =1864.1(10) pm; α =97.68(6), β =101.01(2), γ =105.25(1)°; Z =2). Together with the bridging triflate ligands the cerium atoms form an eight-membered Ce 2 O 4 S 2 ring. Treatment of 1 with 2 equiv. of K[1,3- t Bu 2 C 5 H 3 ] affords the mixed-sandwich complex (COT)Ce(η 5 -1,3- t Bu 2 C 5 H 3 ) ( 2 ) in 78% yield. Furthermore, the preparation of a series of new lanthanide half-sandwich complexes containing the 1,4-bis(trimethylsilyl)cyclooctatetraenyl ligand (=COT″) and additional heteroallylic, aryloxide, and alkyl ligands is reported.

Cyclooctatetraenyl complexes of the early transition metals and lanthanides IX. (Cyclooctatetraenyl)lanthanide diazadiene complexes

Abstract Complexes of the type (COT∗)Ln(DAD)(THF) [Ln = Sm, Yb; COT∗ = 1,4(Me3Si)2C8H6; DAD = 1,4-diazadienes] have been prepared in a ‘one-pot’ reaction by treatment of elemental samarium of ytterbium with equimolar amounts of 1,4-bis(trimethyl-silyl)cyclooctatriene and 1,4-diazadiene ligands, 1H and 171Yb NMR data show that the Sun derivatives contain Sm3+ ions and coordinated DAD radical anions, while in the case of Yb the neutral DAD ligand is coordinated to divalent ytterbium.

Monomere bis(η5-cyclopentadienyl)lanthanoid(III)-komplexe mit raumerfüllenden alkoxid- und thiolat-liganden: Molekülstruktur von (C5H5)2Yb(THF)[SC6H2(CF3)3-2,4,6]☆

Abstract 2,4,6-Tris(trifluoromethyl)phenol (R F OH) reacts with (C 5 H 5 ) 3 Ln (LnNd, Sm, Yb) to give the mononuclear bis(cyclopentadienyl)lanthanide alkoxides (C 5 H 5 ) 2 Ln(THF)(OR F ) [Ln  Nd ( 1 ), Sm ( 2 ), Yb ( 3 ); R F = 2,4,6-tris(trifluoromethyl)phenyl]. Similarly, (C 5 H 5 ) 2 Yb(THFXSR F ) ( 4 ) is obtained upon treatment of (C 5 H 5 ) 3 Yb with 1 equiv. of R F SH. The molecular structure of 4 was determined by X-ray diffraction. Compound 4 is the first mononuclear bis(cyclopentadienyl)lanthanide (III) thiolate complex.

Chemistry of the stable diarylstannylene (RF)2Sn (RF ≡ nonafluoromesityl): oxidative addition reactions

Abstract The preparation of various bis(nonafluoromesityl)tin(IV) derivatives starting from (R F ) 2 Sn ( 1 ) is described (R F ≡ 2,4,6-tris-(trifluoromethyl)phenyl, “nonafluoromesityl”). The fluorination of 1 with XeF 2 affords the corresponding difluoride (R F ) 2 SnF 2 ( 2 ). The dichloro species (R F ) 2 SnCl 2 ( 4 ) has been prepared via a new synthetic route by the treatment of 1 with SnCl 4 . Compound 4 serves as a useful precursor for the synthesis of dibenzoates of the type (R F ) 2 Sn (O 2 CC 6 H 4 R-o) 2 ( 5 , R ≡ H; 6 , R ≡ F). Insertion of 1 into the sulphur-sulphur or selenium-selenium bond of aromatic dichalcogenides provides the tin( IV ) bis(chalcogenolates) (R F ) 2 Sn(EC 6 H 2 R 3 -2,4,6) 2 ( 7 , E ≡ S, R ≡ Me; 8 , E ≡ Se, R ≡ CF 3 ). All new compounds have been fully characterized by spectroscopic methods and elemental analyses.

Redox chemistry of cerocene: the first heterobimetallic organolanthanide complex†

The first heterobimetallic organolanthanide complex containing two different rare earth elements, [Yb(thf)6][Ce- (cot′′′)2]2 2 [cot′′′ = η8-1,3,6-(Me3Si)3C8H5], has been prepared by reacting neutral [Ce(cot′′′)2] with Yb metal in THF; the crystal structure of 2 consists of separated [Yb(thf)6]2+ and [Ce(cot′′′)2]– ions.