Beate Ganter

Convenient synthesis of K[(C5H4MeMnH(CO)2] and reactions with Cl2B[N(SiMe3)2] and B2R2Cl2 (R = Me2N, Me3C)

Abstract A new convenient synthesis for the anionic manganese complex [(C5H4Me)MnH(CO)2]− (1b), from [(C5H4Me)MnH(SiMePh2)(CO)2] and K[BEt3H] is described. Compound 1b which can be isolated on a 15g scale, serves as starting material for the improved syntheses of the borylene complexes [{(C5H4Me)Mn(CO)2}2BR] (2a, b; R = Me2N, Me3C), which are formed in a stiochiometric reaction in good yields. In addition, we report on the synthesis and structure of the salt like compound [{(Me3Si)2N}BH(tmeda)] [{(C5H4Me)Mn(CO)2}2H] (3) showing a Mn-H-Mn unit in solution and in the crystal, which was obtained from the reaction of 1b with [(Me3Si)2N]BCl2.

ENANTIOMERICALLY PURE PHOSPHAFERROCENES WITH PLANAR CHIRALITY

Abstract Enantiomerically pure 2-formyl-3,4-dimethylphosphaferrocene 1 was prepared straightforwardly by resolution of rac-1 via column chromatography on silica of diastereomeric aminals formed of 1 and (R),(R)-1,2-di(N-methylamino)cyclohexane2. Both enantiomers (S)- 1 and (R)- 1 are obtained in 94% yield with ee>99%. The amine 2 is recycled in 89% yield. The absolute configuration of (S)- 1 has been determined by X-ray crystallography.

Reversible Topotactic Hydration and Dehydration of an Europium Complex [1]

Solid samples of the salt [Eu〈LOEt〉2(H2O)2]BF4, (〈LOEt〉 = [CoCp{P(OEt)2O}3]) may be reversibly dehydrated under very mild conditions to give the corresponding mono aqua complex [Eu〈LOEt〉2(H2O)]BF4. The conversion can be monitored by single crystal x-ray diffraction. In the course of the reaction the crystallinity of the substance is retained: both compounds crystallize in space group P21/c with similar lattice constants and essentially the same packing arrangement. The cations show the expected change in the Eu coordination geometry with longer metal-ligand distances for the higher coordinated Eu atoms in the diaqua complex. The crystalline-state reaction is facilitated by a suitable morphology. Reversible topotaktische Anlagerung und Eliminierung eines Aqua-Liganden an einem Europium-Komplex Die ionische Verbindung [Eu〈LOEt〉2(H2O)2]BF4, (〈LOEt〉 = [CoCp{P(OEt)2O}3]) last sich in festem Zustand unter sehr milden Bedingungen zum entsprechenden Mono-Aqua-Komplex [Eu〈LOEt〉2(H2O)]BF4 dehydratisieren. Die Umsetzung kann mit Hilfe der Rontgenbeugung an Einkristallen verfolgt werden. Im Zuge der Reaktion bleibt der einkristalline Charakter der Substanz erhalten: Beide Verbindungen kristallisieren in der Raumgruppe P21/c mit ahnlichen Gitterkonstanten und in den Grundzugen gleicher Packung. Die Kationen zeigen die erwarteten Unterschiede in der Koordinationsgeometrie des Eu mit groseren Metall–Ligand-Abstanden fur das hoher koordinierte Eu Zentralatom im Di-Aqua-Komplex. Eine geeignete Morphologie erleichtert die Reaktion im Einkristall.

{[Bis(dimethylamino) boryl]methyl} dimethylphosphane as ligand in transition metal complexes

Abstract The new α,ω[phosphanyl(organyl)]borane Me2PCH2B(NMe2)2 (8) was obtained in good yield by the reaction of ClB(NMe2)2 with LiCH2PMe2. Compound 8 forms the transition metal complexes [(CO)5Cr{Me2PCH2(NMe2)2}] (9), [(MeC5H4)Mn(CO)2{Me2PCH2B(NMe2)2}] (10), and [(CO)4Fe{Me2PCH2B(NMc2)2}] (11). which were isolated as highly volatile liquids in high yields. Complex 11 easily underwent exchange reactions of the Me2N substituents which led to derivatives with threefold coordinated boron such as [(CO)4Fe{Me2PCH2B(OMe)2}] (13), and [(CO)4Fe{Me2PCH2B(NMe2)Cl}] (14), or to a compound with tetrafold coordinated boron, [(CO)4Fe{Me2PCH2BCl2(NHMe2)}] (15). Li[(CO)4Fe(Me2PCH2BH3)] (16), cis,trans-[{(CO)4Fe(Me2PCH2BH2)}2] (17), and [(CO)4Fe{Me2PCH2BH2(2,4,6-Me3C5H2N)}] (18) were obtained from 13 by corresponding substitution of the MeO groups. The addition of HSiPh3 to the iron center was achieved by photolysis of 13, giving [(CO)3FeH(SiPh3){Me2PCH2B(OMe)2}] (19). [(CO)5Cr{Me2PCH2B(OMe)2}] (12), the chromium analogue of 13, was obtained from the reaction of [(CO)5Cr{Me2PCH2B(NMe2)2}] (9) with MeOH. The structure of compound 19 was determined by single crystal X-ray diffraction.

Fulvene-Like Cationic Phosphaferrocene Species as Synthetically Valuable Intermediates: Preparative and Mechanistic Aspects of the Diastereoselective Formation ofα-Phosphanyl-Substituted 2-Ethylphosphaferrocenes

The slow rate of isomerization of cationic phosphaferrocene species (E)-1 (easily prepared from the parent alcohol) to the more stable (Z)-1 provides selective access to both possible diastereomeric products by addition of nucleophiles from a direction trans to the CpFe moiety. Configurational assignment of the species involved is made on the basis of NMR data and has been confirmed by X-ray structural analysis.

A quest for triple-decker complexes with a bridging phospholyl ligand. Syntheses of [(μ,η5:η5-C4Me4P)()()](BF4)2 and [(μ,η5:η5-C4Me4P)()()](BF4)2, and structures of [ (μ,η1:η5-C4Me4P)](CF3SO3)2(Me2CO) and (C5Me4CH2C6H11)Fe (μ,η1:η5-C4Me4P)

Abstract The new triple-decker complexes [(μ,η5:η5-C4Me4P)( FeCp ∗ )( MCp ∗ )](BF4)2 ( 9 : M = Rh ; 10 : M = Ir ) are obtained from the phosphaferrocene Cp ∗ Fe ( C 4 Me 4 P ) (3a) by electrophilic stacking reactions in acetone. These stacking reactions are suppressed by the presence of even rather weak nucleophiles. In acetonitrile as solvent the σ-bonded complexes [ Cp ∗ Fe (μ,η1:η5-C4Me4P) M ( NCMe ) 2 Cp ∗ ] CF3SO3 ( 11 : M = Rh ; 12 : M = Ir ) are obtained, and Cp ∗ Fe (μ,η1:η5-C4Me4P) Rh ( O 3 SCF 3 ) 2 Cp ∗ (14a) is formed when triflate ions are present in acetone. Nucleophilic degradation of 9 and 10 in acetone produces the corresponding sandwich complexes [ Cp ∗ Rh (C4Me4P)]BF4 (15) (inter alia), and [ Cp ∗ Ir (C4Me4P)]BF4 (16).

Enantiomerically Pure Complexes of Manganese, Iron, and Zirconium with Pinene-Fused Boratabenzene Ligands – Structures ofexo-FeCp*(C13H17BNMe2) and exo,exo-ZrCl2(C13H17BNMe2)2

Complexes of pinene-fused boratabenzene ligands [(1R,9R)6,10,10-trimethyl-4-boratatricyclo[7.1.1.02,7]undeca-2,4,6trienes] C13H17BX (with a: X = NMe2; b: X = OMe; c: X = Me) are described. The lithium salt Li(C13H17BNMe2) [Li(1a)] reacts with [Cp*Fe(NCMe)3]PF6 and with Mn(CO)3Br(py)2 to give diastereomeric mixtures FeCp*(C13H17BNMe2) (4a) and Mn(CO)3(C13H17BNMe2) (7). The mixture 4a undergoes solvolysis in methanol to produce methoxy compounds 4b, which in turn react with LiMe in Et2O to give methyl derivatives 4c. The lithium salts Li(C13H17BX) [Li(1a–c)] react with ZrCl4 in toluene or Et2O to give exo,exo-ZrCl2(C13H17BX)2 complexes (8a–c). The dimethyl derivative exo,exo-ZrMe2(C13H17BNMe2)2 (9) can also be prepared from 8a/LiMe in Et2O. NOE difference spectra have been analyzed to determine the configurations of the diastereomers and to establish a chemical shift criterion for assessing the configuration of the metal–ligand coordination. An independent confirmation of the product stereochemistries has been obtained by single-crystal X-ray structure determinations of exo-4a and 8a.

Nucleophilic Addition of Secondary Phosphines to Cationic Dienyl Tricarbonyliron Complexes: A novel Route to Optically Active Phosphines

Secondary phosphines such as HPPh2 and to the cationic iron dienyl complex [η5 -(1R)-ethylnopadienyl)Fe-(CO)3 ]+ (1) by nucleophilic addition. The phosphonium salt initially formed is readily deprotonated to yield an optically active tertiary phosphine [(n4 -(1 R)-ethylnopadienePPh2 )Fe(CO)3 ] (2b). A similar reaction also occurs with [C6 H7 Fe-(CO)3 ]+ (3) and [C7 H9 Fe(CO)3 ]+ (4) to give [(C6 H7 PPh2 )Fe(CO)3 ] (5) and [(C7 H9 PPh2 )Fe(CO)3 ] (6) in good yields. The mechanism of formation of these novel phosphines is discussed. Complex 2 b crystallizes in the space group P21 21 21 (no. 19); 5 crystallizes in the space group P21 /c (no. 14). Like other monodentate optically active phosphines, 2 b is capable of coordinating to transition metal complexes. It forms palladium complexes on reaction with [{μ-chloro(allyl)palladium}2 ] as well as with [{μ-chloro[(N,N-dimethylamino-kN-2-methyl)phenyl-kC]palladium}2 ] (11). The latter reaction product crystallizes in the space group P31 (no. 144).

A Surprising Adduct of a closo Cluster

The geometry of the Si2 B10 framework remains nearly unchanged when the Si-Si edge is bridged by an electron-donating amido group. This finding is clearly evident from the single-crystal X-ray structure analysis and ab initio calculations of the uprecedented adduct that is formed by the addition of Et2 N- to o-silaborane (structure depicted bottom right).

Synthesis and Structure of 1,2-Diphenyl-1,2-disila-closo-dodecaborane(12), Reaction with [Zr(NMe2)4] and [Ta(NMe2)5]

Diphenyl-o-silaborane (1) can be obtained by sublimation as colourless crystalline material in a yield of 23%. The disilaborane 1 was characterized by NMR spectroscopy, mass spectrometry and X-ray structure analysis. The neutral closo cluster 1 reacts with [Zr(NMe2)4] or [Ta(NMe2)5] to give the dimethylamide adduct [(Me2N)(PhSi)2B10H10]– of the disilaborane. Synthese und Struktur von 1,2-Diphenyl-1,2-disila-closo-dodecaboran(12), Reaktion mit [Zr(NMe2)4] und [Ta(NMe2)5] Fur den closo-Cluster 1,2-Diphenyl-1,2-disila-closo-dodecaboran(12) (1) wird eine Synthese vorgestellt, nach der das Silaboran als farblose Kristalle durch Sublimation in Ausbeuten von 23% erhalten werden kann. 1 wurde durch NMR-Spektroskopie, hochauflosende Massenspektrometrie und eine Kristallstrukturbestimmung charakterisiert. Die Ubergangsmetallamide [Zr(NMe2)4] oder [Ta(NMe2)5] reagieren mit dem Disilaboran 1 zum Dimethylamid-Addukt [(Me2N)(PhSi)2B10H10]–.