Ulrich Behrens

Übergangsmetall—fulven-komplexe : XIV. Kristall- und Molekülstruktur von ferrocenyldiphenylcarbenium-tetrafluoroborat, [Cn5H5FeC5H4C(C6H5)2]+ BF4-. Ein Fulven-eisen-komplex?

Abstract The structure of ferrocenyldiphenylcarbenium tetrafluoroborate has been determined by single crystal X-ray analysis. The compound crystalizes in the orthorhombic space group P 2 1 cn with lattice constants a 905.1(3), b 1087.0(7), c 1964.4(9) pm; Z  4. The final R index for 1525 observed reflections of non-zero weight ( F ⪢ 2 σ) is 0.040. The molecule can be described as a fulvenecyclopentadienyliron cation with the fulvene exocyclic double bond bent to the iron (angle 20.7°) and an FeC exo distance of 271.5 pm.

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.

Neodym(III)komplexe mit stark raumerfüllenden Cyclopentadienyl- und Benzamidinat-Liganden: Ein Vergleich

Abstract [Cp** 2 Nd(μ-CI)] 2 ( 1 ) has been prepared by treatment of NdCI 3 (THF) 2 with two equivalents of KCp** (Cp** = 1,3-di-t-butylcyclopentadienyl). Similarly, Li[(CF) 3 ) 3 C 6 H 2 C(NSiMe 3 ) 2 ] reacts with NdCl 3 (THF) 2 to give [(CF 3 ) 3 C 6 H 2 C(NSiMe 3 ) 2 ] 2 Nd(μ-Cl) 2 Li(THF) 2 ( 2 ). Recrystallization of 2 from DME/hexane yields the binuclear derivative (μ-DME)[{(CF 3 ) 3 C 6 H 2 C(NSiMe 3 ) 2 } 2 Nd(μ-Cl) 2 Li(THF)] 2 ( 3 ). The molecular structures of 1 , 2 and 3 have been determined by X-ray diffraction. The 2,4,6-trisub- stituted benzamidinate anion [(CF 3 ) 3 C 6 H 2 C(NSiMe 3 ) 2 ] − can be regarded as a steric equivalent of bulky cyclopentadienyl ligands such as Cp* or Cp**.

Carbonyl-eisen-komplexe von pentafulvenen

Abstract The structures and spectroscopic properties (IR, NMR) of coordination compounds formed by the reaction of diphenylfulvene, dimethylfulvene and diethylfulvene with Fe 2 (CO) 9 are reported. Single-crystal X-ray diffraction studies of bis(dimethylfulvene)pentacarbonyldiiron and diphenylfulvenepentacarbonyldiiron have been made. The covalent single-bond radius of iron in the η-cyclopentadienyldicarbonyliron and η-allyltricarbonyliron group has been found to be 1.38 A. Chemical bonding in diphenylfulvenepentacarbonyldiiron and 6-dimethylaminofulvenylfulvenepentacarbonyldiiron has been studied using the simple HMO-model.

Novel 18-crown-6 organometallic rubidium and cesium complexes containing cyclopentadienyl, indenyl, pentamethylcyclopentadienyl, and fluorenyl as carbanions

Abstract The synthesis of base-free cyclopentadienyl-, indenyl-, pentamethylcyclopentadienyl-, and fluorenylrubidium and -cesium is described. Reactions of these compounds with the hexadentate Lewis base 18-crown-6 yielded new complexes of the type [MR(18-crown-6)] and [{RbFl(18-crown-6)}2(L)] (M=Rb, Cs; R=Cp, Ind, Cp*, Fl; L=dimethoxyethane, dioxane). All complexes were characterized by NMR spectroscopy and X-ray structure analysis. The dominating structure element in the investigated complexes is an [MR(18-crown-6)] unit in which the alkali metal ion is in close contact with the six oxygen atoms of the crown ether. In addition, a multihapto π-interaction between the cation and carbanion was found. For all isolated complexes containing the fluorenyl ligand, [MFl(18-crown-6)] and [{RbFl(18-crown-6)}2(L)], only a η2 coordination of the aromatic C–C bond between the C5- and C6-ring to the metal ions was observed.

Cyclopentadienyl, indenyl, fluorenyl, and pentamethylcyclopentadienyl complexes of potassium with 18-crown-6

Abstract The first 18-crown-6 Lewis base adducts of potassium organometallic compounds are described. The mononuclear complexes [KCp(18-crown-6)] (1), [KCp*(18-crown-6)] · 0.5THF (2a), [KInd(18-crown-6)] (3), [KFl(18-crown-6)] · 0.5toluene (4), and [{KFl(18-crown-6)}{KFl(18-crown-6)(THF)}] (5) and the binuclear complex [{KFl(18-crown-6)}2(DME)] (6) were synthesised and single-crystal X-ray diffraction analyses were carried out (Cp=cyclopentadienyl, Cp*=pentamethylcyclopentadienyl, Ind=Indenyl, Fl=Fluorenyl). The influence of the neutral ligand on the potassium–anion-interaction is discussed in a comparative study.

Metallorganische verbindungen des kupfers: VII. Synthese und struktur von alkin-alkinyl-kupfer(I)-komplexen (alkin = 3,3,6,6-tetramethyl-1-thia-4-cycloheptin; alkinyl = CCC6H5, CCtC4H9)

Abstract The copper(I) complexes [CuX(tmtch)] 2 and [(CuX) 2 (dms)(tmtch)] n (X  Cl, Br; dms = dimethylsulfide; tmtch = 3,3,6,6-tetramethyl-1- thia-cyclohept-4-yne) react with ethynyllithium compounds (LiCCC 6 H 5 , LiCC t C 4 H 9 ) using halide substitution to form the previously unknown alkyne-alkynyl-copper(I)-complexes [CuCCC 6 H 5 (tmtch)] 2 ( 2 ) and [(CuCC t C 4 H 9 ) 4 (tmtch) 2 ] ( 3 ). Both novel complexes have been characterized by X-ray diffraction studies.

übergangsmetall-fulven-komplexe: VII. tricarbonyl(fulven)-metall-komplexe der sechsten nebengruppe

Abstract A universal method for synthesizing tricarbonyl(fulvene)metal complexes of Group VIa is described. The compounds are formed by reaction of the fulvenes with the tris(acetonitril) complexes, (CH3CN)3M(CO)3 (M = Cr, Mo, W), and they have been characterized spectroscopically. The tricarbonyl(fulvene)chromium compounds react with alkyllithium to form anions of substituted cyclopentadienyl complexes.

Metallorganische Verbindungen des Kupfers. Synthese und Struktur von komplexen des 3,3,6,6-Tetramethyl-1-thia-4-cycloheptins mit Kupfer(I)-Halogeniden

Abstract 3,3,6,6-Tetramethyl-1-thia-4-cycloheptyne (C 10 H 16 S) ( 1 ) reacts with copper(I)-halogenides-dimethylsulfid to give η 2 -(CC) coordinated copper complexes [(C 10 H 16 S) 2 CuX] 2 ( 2 ) (X = Cl, Br, I). Reaction of CuCl(dms) with 0.5 mol of C 10 H 16 S ( 1 ) in the presence of dimethylsulfide yields the polymeric complex [(C 10 H 16 S)Cu 2 Cl 2 (CH 3 SCH 3 )] n ( 3 ). X-ray diffraction studies of 2a (X = Cl) and 3 confirm the η 2 -(CC) coordination of the thiacycloheptyne ligand 1 in both complexes. Additional coordination of the sulphur atom to copper in complex 3 leads to a polymeric structure.

Übergangsmetall-fulven-komplexe: XXVIII. Reaktionen von (fulven)Cr(CO)3-komplexen und α-ferrocenyl-carbeniumionen mit nukleophilen☆

Abstract Tricarbonyl(fulvene)chromium complexes react with anionic nucleophiles to give functionally substituted cyclopentadienyl derivatives. The nucleophilic attack occurs at the exocyclic carbon atom of the fulvene ligand. Addition of PPh2− to (η6-6,6-dimethylfulvene)Cr(CO)3 (1) yields the novel anion [(η5-C5H4C(CH3)2PPh2)Cr-(CO)3]−, which can be isolated as a K+, (C2H5)4N+, (C6H5)4P+, or Tl+ derivative (2–5). The potassium salt of the uncoordinated C5H4C(CH3)2PPh2− anion (7) is obtained by treatment of 6,6-dimethylfulvene with KPPh2·2C4H8O2. Similarly, NaC5H5 reacts with 1 to give Na[(η5-C5H4C(CH3)2C5H5)Cr(CO)3] (8). The reactions of (6-dimethylaminofulvene)Cr(CO)3 (15) with nucleophiles are accompanied by elimination of dimethylamine. Addition of Ph3PCH2 to 15 gives an unstable product, but after reaction of 6-dimethylaminofulvene with Ph3PCH2, the free ligand C5H4CHCHPPh3 (17) can be isolated in moderate yields. Deeply colored anions of the type [(η5:η5-C5H4C(R)C5H4)Cr2(CO)6]− (R = H, N(CH3)2) are synthesized by reaction of 15 or (6-dimethylamino-6-methylthiofulvene)Cr(CO)3 with NaC5H5 and subsequent complexation of the mononuclear intermediate with (CH3CN)3Cr(CO)3. In addition, the synthesis of the new fulvene complexes [C5H4CH(CHCH)2N(CH3)Ph]M(CO)3 (23, 24; M = Cr, Mo) is described. The investigation is extended to α-ferrocenylcarbenium ions, which are isoelectronic with (fulvene)Cr(CO)3 complexes. [(η5-C5H5)Fe(C5H4CPh2)]+ BF4− (25) adds tertiary phosphines at the exocyclic carbon atom to give phosphonium salts of the type [(η5-C5H5)Fe(C5H4CPh2PR3)]+BF4−. A CO-substititution product of a tricarbonyl (fulvene)chromium complex is obtained for the first time by irradiation of (η6-6,6-diphenylfulvene)Cr(CO)3 in the presence of PPh3. In addition, an improved synthesis of the (CH3CN)3M(CO)3 complexes (M = Cr, Mo, W) is reported.