Holger Hemling

XLVIII. Synthese und struktur der ersten neutralen Tris(allyl) lanthanoid-komplexe La(η3-C3H5)3 · 1,5 Dioxan und Nd(η3-C3H5)3 · Dioxan und ihre Eignung als “single site” -Katalysatoren für die stereospezifische Butadienpolymerisation

Abstract The title complexes are synthesized from the tetrakis(allyl)lanthanide(III) complexes Li[Ln(C 3 H 5 ) 4 ] · 1,5 dioxane (Ln = La or Nd) by allyl lithium abstraction with BEt 3 in dioxane. The compounds were characterized by elemental analysis, by IR, 1 H and 13 C NMR spectroscopy and also by X-ray crystal structure analysis. In both complexes the three allyl anions are η 3 coordinated. By the coordination of dioxane in the case of lanthanum the dimeric structure [{La( η 3 -C 3 H 5 ) 3 ( η 1 -C 4 H 8 O 2 )} 2 ( μ -C 4 H 8 O 2 )] ( 1 ) with neodymium a polymeric structure [Nd( η 3 -C 3 H 5 ) 3 ( μ -C 4 H 8 O 2 )] n ] ( 2 ) is formed. The dioxane can be split off easily at 50°C without further decomposition. Compounds 1 and 2 catalyze the 1,4- trans polymerization of butadiene in toluene with high selectivity. By addition of proper Lewis acids, such as Et 2 AlCl, EtAlCl 2 or (MeAlO) x , catalysts for the 1,4- cis polymerization are obtainable. The results allow first conclusions on the mechanism of the lanthanide-complex-catalyzed butadiene polymerization.

A New Synthesis of Hydrophilic Carboxylated Arylphosphines

Abstract An efficient synthetic procedure for the preparation of versatile functionally substituted arylphosphines from commercially available starting materials is reported together with alternative synthetic routes for (carboxyphenyl)diphenyl phos-phines.

Effects of changes in the ligands on the skeleton and the catalytic activity of some new rhodium complexes with pyrazolato moieties

Abstract Whereas the reaction of [Rh(CO) 2 (μ-pz)] 2 (where pz is either a pyrazolato or 3,5-dimethylpyrazolato group) with 3-(diphenylphosphino)benzoic acid and (2-formylphenyl) diphenylphosphine gives the dinuclearic complexes [Rh(CO)(Ph 2 P-3-C 6 H 4 COOH)(μ- pz)] 2 ( 1 and 2 ) and [Rh(CO)(Ph 2 P-2-C 6 H 4 CHO)(μ-pz)] 2 ( 5 and 6 ) respectively, 2-(diphenylphosphino)benzoic acid gives the monorhodium compounds R h(CO)(H-pz)(Ph 2 P-2-C 6 H 4 COO ) ( 3 and 4 ). The structures of Rh(CO) ( NCHCHCHN H)(Ph 2 P-2-C 6 H 4 COO) ( 3 ) and [Rh(CO)(Ph 2 P-2-C 6 H 4 CHO)(μ- NCMeCHCMeN )] 2 ( 6 ) have been determined by X-ray diffraction analyses. Both, the monorhodium and the dirhodium complexes catalyse the hydroformylation of acyclic and cyclic olefins at 120°C and at CO and H 2 pressures of 28 atm. At 70–90°C the dinuclear complexes with 3-(diphenylphosphino)benzoic acid moieties are substantially more active than the monorhodium compounds.

Metallorganische Verbindungen der Lanthanoide. LXXVIII: Bis(pentamethylcyclopentadienyl)[4-(1,2,3,4,5-pentamethylcyclopentadien-1-yl)butoxy](tetrahydrofuran)lanthanoide

Abstract LnCl 3 (LnLa, Nd, Tm, Lu) reacts with NaCp* (Cp*C 5 (CH 3 ) 5 ) in THF to yield the complexes Cp* 2 Ln[O(CH 2 ) 4 Cp*(THF) ( 1 = La, 2 = Nd, 3 = Tm, 4 = Lu). Crystals of 2 are monoclinic, space group C 2/ c with a 2999.8(6), b 1396.1(3), c 1740.0(3) pm, s 90.54(1)°, V 7287(3) × 10 −3 m 3 and Z = 8. Least-squares refinement on the basis of 4680 reflections ( F o >4σ( F o )) led to a final R value of 0.0268. 4 crystallizes monoclinic, space group C 2/ c with a 2965.4(5), b 1384.6(3), c 1740.6(4) pm, s 90.81(1)°, V 7146(3) × 10 −30 m 3 and Z = 8. Least- squares refinement on the basis of 4097 reflections ( F o >4σ( F o )) led to a final R value of 0.028.

Metallorganische verbindungen der lanthanoide XCVI. Ylidartige olefinkoordination in komplexen dreiwertiger 4f-elemente☆

Abstract [(Me 3 Si) 2 N] 3 Ln (Ln  La ( 1 ) or Nd ( 2 )) and (C 8 H 8 Y(C 5 Me 5 ) ( 3 ) react with 1,3,4,5-tetramethyl-2-methylenimidazolin ( 4 ) to yield the ylidic olefin complexes [( Me 3 Si) 2 N]Ln[CH 2  CN(Me)C(me)C(Me)N (Me) ] (Ln  La ( 5 ) or Nd ( 6 )) and (C 8 H 8 )Y(C 5 Me 5 )[CH 2  CN(Me)C(me)N (Me)] ( 7 ). The molecular structures of 6 and 7 have been determined by X-ray diffraction.

SYNTHESIS AND ESR-CHARACTERIZATION OF RADICAL ANION COMPLEXES OF LANTHANUM. X-RAY CRYSTAL STRUCTURE OF THE MIXED BIPY, BIPY-1 COMPLEX OF LANTHANUM(III ) LAI2(BIPY)(BIPY)(DME) : EVIDENCE FOR AN INTER-LIGAND CHARGE TRANSFER

Abstract The reaction of [LaI2(THF)3]2[C10H8] with excess of 2,2′-bipyridine (bipy) in DME or THF results in the formation of mixed radical anion ligand/neutral ligand complexes [LaI2(bipy(0))(bipy(−1))(L)n (DME)(1) and (THF)2 (2), whereas a reactant reactant ratio of 1:2 generates the mono-bipy complex [LaI2(bipy)(DME)2] (3). ESR and IR spectroscopic data show a fast shuttle electron transfer (SIET) between the neutral and the radical anion of bipy in1 and2. The X-ray structure shows1 to be monoclinic, space group P2/c, Z = 2, with a = 10.0320(12), b = 9.7510(11), c = 16.296(8)A˚, β = 90.43(2)°. The structure was refined toR = 0.0360 for 2562 observed reflections (1 > 2σ(1)). It shows the lanthanum atom eight-coordinated by two iodine, two oxygen and four nitrogen atoms.

SYNTHESIS, MAGNETIC SUSCEPTIBILITY AND X-RAY CRYSTAL STRUCTURE OF (TBUNCHCHNTBU)3YB

Abstract The reaction of (C 10 H 8 )Yb(THF) 3 with t BuNCHCHN t Bu ( t Budad) in tetrahydrofuran at room temperature leads to Yb( t Budad) 3 ( 1 ), which is also obtained from the reaction of YbCl 3 and three molar equivalents of K( t Budad) in tetrahydrofuran or by metal vapor synthesis. 1 has been characterized by X-ray diffraction. The crystals are monoclinic, space group C 2, Z = 2 with a = 1034.8(9), b = 1710.4(6), c = 1020.4(8) pm, β = 113.28(2)°. The structure was refined to R = 0.0274 for 1466 observed reflections ( F O > 4 σ ( F O )). The structure shows that the empirical composition is Yb( t Budad) 3 and that the coordination number of Yb is six, but the X-ray data are not sufficiently accurate to judge if the oxidation state of ytterbium is zero, two or three. The magnetic susceptibility of solid 1 , prepared by metal vapor synthesis, was studied from 5 to 300 K. The magnetic results are explained by postulating that the bivalent ytterbium species [Yb II ( t Budad)] predominates at low temperature and as the temperature increases the trivalent ytterbium species [Yb III ( t Budad − ) 3 ] predominates in the solid state.

Homogeneous and biphasic oligomerization of terminal alkynes by some water soluble rhodium catalysts

Abstract The catalytic activity of six water soluble rhodium compounds, RhCl3·3H2O 1, RhCl(Ph2PC6H4-3-SO3Na)3·4H2O 2, (COD)RhCl(Ph2PC6H4-3-SO3Na)·H2O 3, [(COD)Rh(μ-Ph2PC6H4-3-SO2-O)]24, [(CO)Rh(Ph2PC6H4-3-CO2H)(μ-SPh)]25, and [Rh3O(OAc)6-(H2O)3]OAc 6, for oligomerization of model hydrophilic and lipophilic terminal alkynes was investigated under homogeneous and under biphasic conditions. While propynoic acid 7 is converted by all six catalysts solely into trimellitic acid, 8, and trimesic acid, 9, phenylacetylenes 10 either dimerize, trimerize or give stereoregular polymers. The nature of the oligomerization products proved to depend on the catalyst, the medium and the reaction temperature. In acetonitrile, complex 4 transforms the various phenylacetylenes (except 4-nitrophenylacetylene, 10f) mainly or entirely to the head-to-tail dimers, 13, which undergo thermal rearrangement to the head-to-head isomers, 14.

A Novel Convenient Synthesis of Aryl Phosphines Containing Reactive Functional Groups

Abstract A convenient method is described for the preparation of Ph2PC6H4COOH-2 (2) and Ph2PC6H4CHO-2 (5).

Intramolekular stabilisierte gallium- und indiumorganyle: Synthese und röntgenstrukturanalyse repräsentativer bis- und tris[3-(dialkylamino) propyl]gallium- und -indium-derivate

Abstract The intramolecularly stabilized organogallium and organoindium compounds ClGa(CH 2 CH 2 CH 2 NMe 2 ) 2 ( 1 ), RIn(CH 2 CH 2 CH 2 NMe 2 ) 2 (R = Cl, Br, I, CN, SCN, CF 3 CC, MeCC, Me 3 SiCC, C 6 F 5 O, CF 3 CO 2 , CF 3 , i C 3 F 7 ,( 2a–13a ), RIn(CH 2 CH 2 CH 2 NEt 2 ) 2 (R = Cl, I, CN, CF 3 CC, MeCC, Me 3 SiCC, C 6 F 5 O, CF 3 CO 2 ( 2b , 4b , 5b , 7b–11b ) ClGa(C 6 H 4 CH 2 NMe 2 -2) 2 ( 14 ), ClIn(C 6 H 4 CH 2 NMe 2 -2) 2 ( 15 ), and ClIn[CH 2 CH 2 CH 2 N(CH 2 ) 5 ] 2 ( 16 ) a well as the homoleptic compounds GaR 3 (R = CH 2 CH 2 CH 2 NMe 2 ( 17 ), CH 2 CHMeCH 2 NMe 2 ( 18 ), C 6 H 4 CH 2 NMe 2 -2 ( 19 ) and In(CCCF 3 ) 3 (THF) 2 ( 20 ) have been synthesized from gallium trichloride or indium trichloride and the corresponding ω-aminoorganyl lithium compounds, by the reaction of 2a and 2b with the appropriate RLi, or from Cd(CH 2 CH 2 CH 2 NMe 2 ) 2 and RInBr 2 (R = CF 3 , i C 3 F 7 ). The 1 H-, 13 C-NMR and mass spectra of the new compounds as well as the X-ray crystal structure analyses of 1 , 4a , 14 , 17 , 19 and 20 are reported and discussed.