Michael Wedler

Organoactinoid-Komplexe : Substituierte Benzamidinat-Anionen als sterische Äquivalente zu η5-C5H5 und η5-C5Me5. Molekülstrukturen von [PhC(NSiMe3)2]3UCl, [4-CF3C6H4C(NSiMe3)2]3UCl, [2,4,6-(CF3)3C6H2C(NSiMe3)2]2UCl2 und [2,4,6-(CF3)3C6H2C(NSiMe3)2]2ThCl2

The reaction of substituted benzonitrile derivatives with LiN(SiMe3)2 or NaN(SiMe3)2 yields N,N′-bis(trimethylsilyl)benzamidinates Li[RC6H4C(NSiMe3)2] (1) and Na[RC6H4C(NSiMe3)2] (2) (R = H, Me, OMe, CF3) respectively. 2,4,6-Trisubstituted derivatives, Li[R3C6H2C(NSiMe3)2] (3: R = CF3, 4: R = Me) are available by addition of R3C6H2Li to Me3SiNCNSiMe3. The N,N′-bis(trimethylsilyl)benzamidinate anions can be regarded as steric equivalents of η5-C5H5 and η5-C5Me5. The alkali metal derivatives 1 and 2 react with UCl4 to give substituted benzamidinato-uranium(IV) chlorides. Depending on the stoichiometry, complexes of the type [RC6H4C(NSiMe3)2]2UCl2 (5) and [RC6H4C(NSiMe3)2]3UCl (6) can be isolated. Sterically more demanding ligands [R3C6H2C(NSiMe3)2]− give exclusively the disubstituted products [R3C6H2C(NSiMe3)2]2UCl2 (7: R = CF3, 8: R = Me). The thorium(IV) complexes [(CF3)3C6H2C(NSiMe3)2]2ThCl2 (9) and [CF3C6H4C(NSiMe3)2]3ThCl (10) can similarly by synthesized. The structures of [PhC(NSiMe3)2]3UCl (6a), [4-CF3C6H4C(NSiMe3)2]3UCl (6d), [2,4,6-(CF3)3C6H2C(NSiMe3)2]2UCl2 (7) and [2,4,6-(CF3)3C6H2C(NSiMe3)2]2ThCl2 (9) were determined by X-ray crystallography.

Struktur und reaktivität von ytterbiumbenzamidinaten

Abstract The ytterbium(II) benzamidinates [RC6H4C(NSiMe3)2]2Yb(THF)2 (1a: R  H, 1b: R  OMe) react with diaryl diselenides and ditellurides to give ytterbium(III) complexes of the type [RC6H4C(NSiMe3)2]2Yb(SeR′)(THF) (2: R  H, R′  Ph; 3: R  H, R′  Mes) and [RC6H4C-(NSiMe3)2]2Yb(TeR′)(THF) (4: R  OMe, R′  Mes), respectively. The molecular structure of [PhC(NSiMe3)2]2Yb(SeMes)(THF) (3) has been determined by X-ray crystallography (triclinic, space group P 1 , a 1064.9(3), b 1377.1(3), c 3690(3) pm, α 68.61(2), β 89.46(3), γ 72.82(1)°, Z = 4, 10531 observed reflexions, R = 0.045). Moreover the strongly temperature-dependent 1H NMR spectra of 2 and 3 are discussed and 171Yb NMR spectra of some ytterbium(II) chelate complexes are reported.

Dimere Alkalimetallbenzamidinate: Einfluß des metallions auf die struktur

Abstract The molecular structures of two N -silylated alkali metal benzamidinates, [MeC 6 H 4 C(NSiMe 3 ) 2 -Li(THF)] 2 1 and [PhC(NSiMe 3 ) 2 Na(Et 2 O)] 2 ·Et 2 O 2 , have been determined by low temperature X-ray diffraction studies. Both compounds are dimeric in the solid state but the molecular structures are strongly influenced by the alkali metal used. The NaNa distance in 2 is unusually short (274.1 pm). The preparation of K[PhC(NSiMe 3 ) 2 ] ( 3 ) is also described.

Nichtklassische organolanthanoid(II)komplexe: Darstellung und reaktivität der ersten organoneodym(II)verbindung

Abstract NdCl 2 (THF) 2 reacts with KCp ★ to give [K(THF) n ] 2 [Cp 2 ★ NdCl 2 ] ( 1 ) which represents the first divalent organoneodymium complex. Treatment of 1 with t BuCl, [Me 2 NC(S)S] 2 or MesSeSeMes affords the organoneodymium(III) complexes Cp 2 ★ NdCl(THF) ( 2 ), Cp 2 ★ Nd(S 2 CNMe 2 ) ( 3 ) and Cp 2 ★ NdSeMes(THF) ( 4 ) (Cp ★ = η 5 - pentamethylcyclopentadienyl).

Organoactinoid-Komplexe: II. (Benzamidinato)uran(IV)-chloride; Neue Ausgangsmaterialien für die Organoactinoid-Chemie☆☆☆

Zusammenfassung The synthesis of [PhC(NSiMe3)2]2UCl2 (2) and [PhC(NSiMe3)2]3UCl (3) from Li[PhC(NSiMe3)2] (1) and UCl4 is described. The complexes 2 and 3 represent a novel class of precursors for organoactinide chemistry. A uranium(VI) derivative, [PhC(NSiMe3)2]2UO2 (4), is obtained by treatment of UO2Cl2 with 1.

Actinidkomplexe mit Tripodliganden: Synthese und Struktur von [CpCo{P(O)(OEt)2}3]UCl3(THF)

The reaction of UCl4 with Na[CpCo{P(O)(OEt)2}3] (1) in THF yields the monosubstituted derivative [CpCo{P(O)(OEt)2}3]UCl3(THF) (2). The coordinated THF molecule in 2 is easily removed under vacuum to give [CpCo{P(O)(OEt)2}3]UCl3 (3). ThCl4 reacts with 1 to give the disubstituted product [CpCo{P(O)(OEt)2}3]2ThCl2 (4). A mixed-ligand cyclopentadienyl uranium complex, [CpCo{P(O)(OEt)2}3]CpUCl2 (5) is obtained by treatment of CpUCl3(THF)2 with 1.

σ-Ferrocenyl-Komplexe der frühen Übergangsmetalle – Synthese und Struktur / σ-Ferrocenyl Complexes of the Early Transition Metals – Synthesis and Structure

Abstract Ferrocenyllithium, FcLi (1), reacts with (C5H4CH3)2TiCl2, CpTiCl, and Cp*TiCl 3 to give the new σ-ferrocenyl complexes (C5H4CH3)2TiFc2 (2), CpTiFc3 (3) and Cp*Ti(Fc)2Cl (4), respectively. Treatment of Cp*2ZrCl2 with FcLi yields the mono-substitution product Cp*2Zr(Fc)Cl (5), which has been characterized by an X-ray structure analysis. Compound 5 crystallizes in the monoclinic space group P21/c (a = 1622.3(6), b = 995.0(2), c = 1664.3(6) pm; β = 94.78(3)°; Z = 4). Due to the sterically demanding pentamethylcyclopentadienyl ligands 5 contains a long zirconium-carbon bond (231.4(8) pm) and the Cp rings of the ferrocenyl substituent are tilted by 10.2°. The syntheses of CpZrFc3 (6), Cp*HfFc3 (7) and Cp2VFc2 (8) are also described.

Inorganic Ring Systems Containing Lanthanide Elements

Abstract Lanthanide complexes containing fourmembered N-C-N-Ln, N-S-N-Ln and N-P-N-Ln rings have been synthesized by treatment of lanthanide halides with bulky anionic chelating ligands. Similar ring systems containing four different elements (N-Si-0- Ln) have been obtained by reacting anhydrous lanthanide trichlorides with Li[Me2Si(OtBu)(NtBu)]. A twelve-membered inorganic ring is formed during the reaction of Cp∗2Sm(THF)2 with [Cp∗Fe(CO)2]2.