Wolfgang Brüser

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.

Silsesquioxane Chemistry II. Tin(IV) and Hafnium(IV) Compounds of Silsesquioxanes

Summary. Four complexes of silsesquioxanes with di- and triorganotin(IV) cations have been prepared; their composition was determined by standard analytical and spectroscopic methods. The results show that complexes containing an organotin(IV) moiety and the ligand in a 1:1 ratio are formed. FTIR spectra are consistent with the presence of Sn*O vibrations in the compounds. The structure of the complexes is discussed on the basis of Mößbauer and multinuclear (1H, 13C, 119Sn, and 29Si) NMR spectroscopic measurements. Comparison of the experimental quadrupole splitting (QS) with that calculated on the basis of the partial quadrupole splitting (PQS) concept revealed that the complexes formed with dialkyltin(IV) cations as well as the trialkyl derivatives have a regular tetrahedral structure. A new organohafnium silsesquioxane derivative ([Cy7Si7O12Hf(C5Me5)], Cy=cyclohexyl, 5), was prepared by treatment of [Cy7Si7O9(OH)3] with (C5Me5)HfMe3 under elimination of methane. The molecular structure of 5 was determined by X-ray crystallography.Zusammenfassung. Vier Komplexe von Silsesquioxanen mit Di- und Triorganozinn(IV)-Kationen wurden hergestellt; ihre Zusammensetzung wurde mit analytischen und spektroskopischen Standardmethoden bestimmt. Die Ergebnisse zeigen, daß in den gebildeten Komplexen Organozinneinheit und Ligand im Verhältnis von 1:1 vorhanden sind. FTIR-Spektren stehen im Einklang mit dem Auftreten von Sn*O-Schwingungen in den Verbindungen. Die Struktur der Komplexe wird auf der Grundlage von Mößbauer-Spektren und multinuklearen NMR-Experimenten (1H, 13C, 119Sn, 29Si) diskutiert. Ein Vergleich der experimentell beobachteten Quadrupolaufspaltung (QS) mit nach dem Konzept der partiellen Quadrupolaufspaltung (PQS) berechneten Werten ergab sowohl für die mit dem Dialkyzinn(IV)-Kation gebildeten Komplexe als auch für die Trialkylderivate eine regelmäßige tetraedrische Struktur. Ein neues Organohafniumsilsesquioxanderivat ([Cy7Si7O12Hf(C5Me5)], Cy=Cyclohexyl, 5) wurde durch Umsetzung von [Cy7Si7O9(OH)3] mit (C5Me5)HfMe3 unter Abspaltung von Methan hergestellt; seine Molekülstruktur wurde mittels Röntgenstrukturanalyse bestimmt.

Imidotitanium Complexes with Heteroallylic Ligands: Synthesis and Solid‐State Structure

Treatment of Ti(NtBu)Cl2(py)2 (1, py = pyridine) with bulky heteroallylic ligands in a 1:1 molar ratio affords the monosubstituted derivatives [PhC(NSiMe3)2]Ti(NtBu)Cl(py)2 (2), [MeOC6H4C(NSiMe3)2]Ti(NtBu)Cl(py) (3), and [Ph2P(NSiMe3)2]Ti(NtBu)Cl(py) (4). Similarly, 2:1 reactions afforded the disubstitution products [PhC(NiPr)2]2Ti(NtBu)(py) (6) and [Ph2P(NSiMe3)2]2Ti(NtBu) (7). The bis(pyridine) adduct Ph2P(NSiMe3)2Li(py)2 (5) was isolated as a by-product during the preparation of 4. The molecular structures of 7 has been established by X-ray crystallography.

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.

Si–O–based inorganic ring systems containing f-elements: structural characterization of novel siloxanediolates of the lanthanides and actinides†

Depending on the reaction conditions and the ionic radius of the lanthanide ion, tetraphenyldisiloxanediol, (Ph2SiOH)2O, reacts with [Ln{N(SiMe3)2}3{LiCl(thf)3}3] (Ln = Eu, Gd, Sm) to afford novel heterobimetallic rare earth disiloxanediolates, some of which can be regarded as ‘inorganic lanthanide metallocenes’; a ring expanded uranium(VI) derivative, [U{Ph2Si(OSiPh2O)2}2{(Ph2SiO)2O}] 4, is formed upon treatment of uranocene, [U(η8-C8H8)2], with (Ph2SiOH)2O.