Hans-Georg Schmidt

Metallocene analogues containing bulky heteroallylic ligands and their use as new olefin polymerization catalysts

Abstract A series of Ti and Zr metallocene analogues containing bulky benzamidinate ligands has been prepared and fully characterized. Treatment of TiCl 4 (THF) 2 or ZrCl 4 (THF) 2 with two equivalents of the appropriate benzamidinate anions affords the bis(benzamidinato) complexes [C 6 H 5 C(NC 3 H 7 ) 2 ] 2 MCl 2 (M=Ti ( 1 ), Zr ( 2 )) and [C 6 H 5 C(NC 6 H 11 ) 2 ] 2 MCl 2 (M=Ti ( 3 ), Zr ( 4 )). The zirconium complex 2 was structurally characterized by X-ray diffraction. In a similar manner the nonafluoromesityl derivative [(CF 3 ) 3 C 6 H 2 C(NC 6 H 11 ) 2 ] 2 ZrCl 2 ( 5 ) was synthesized from ZrCl 4 (THF) 2 and Li[(CF 3 ) 3 C 6 H 2 C(NC 6 H 11 ) 2 ]. Methylation of 4 with methyllithium yields the dimethyl complex [C 6 H 5 C(NC 6 H 11 ) 2 ] 2 ZrMe 2 ( 6 ). The mixed-ligand metallocene analogues [C 6 H 5 C(NC 3 H 7 ) 2 ](C 5 Me 5 )MCl 2 (M=Ti ( 7 ), Zr ( 8 )) and [C 6 H 5 C(NC 6 H 11 ) 2 ](C 5 Me 5 )TiCl 2 ( 9 ) have been prepared by reacting (C 5 Me 5 )TiCl 3 or (C 5 Me 5 )ZrCl 3 with one equivalent of a lithium N , N ″-dialkylbenzamidinate. The polymerization of ethylene and propylene has been studied by the catalytic precatalyst complexes 1 and 2 upon reaction of an excess of methylalumoxane to obtain the active cationic complexes. The polymerization activity of the complexes is comparable to other benzamidinate ancillary containing ligands although toward shorter amounts of time due to a competitive inhibition presumably obtained by a β -hydrogen elimination from the ligand. Polymerization activity is strongly dependent on catalyst and cocatalyst concentrations and on temperature.

A new inorganic metallocycle containing tin, sulphur, phosphorus and nitrogen. Crystal and molecular structure of spirobicyclic Me2Sn(SPPh2NPPh2S)2

Abstract A new inorganic heterocycle is obtained by reacting potassium tetraphenyldithioimidodiphosphinate with trimethyltin and dimethyltin chlorides, in benzene. X-ray diffraction analysis reveals a spirocyclic structure with the dimethyltin moiety as the coordination centre with non-planar six-membered SnS 2 P 2 N rings. The coordination at tin is nearly perfectly octahedral, with equal SnS [273.3(2) and 273.7(2) pm] and PS bonds [200.9(3) and 201.9(3) pm]. The SSnS and H 3 CSnCH 3 units are co-linear.

[Zn2(thf)2(EtZn)6Zn4(μ4‐O)(tBuPO3)8]: A Dodecanuclear Zincophosphonate Aggregate with a Zn4(μ4‐O) Core

The largest multinuclear zinc framework synthesized is in the title compound (see picture), which contains structural features closely related to the motifs found in layered and three-dimensional zincophosphates and zincophosphonates. The reactive centers make this zincophosphonate a viable precursor for the synthesis of porous zincophosphonate materials.

Synthesis and structure of monomeric and solvent-free LPrX2 compounds supported by a new β-diketiminato ligand [L = Et2NCH2CH2NC(Me)CHC(Me)NCH2CH2NEt2, X = Cl, Br, BH4]

Abstract Trivalent praseodymium complexes with a new β-diketiminato ligand, possessing two pendant arms, LPrX2, (X=Cl (3), Br (4), BH4 (5)), have been prepared by the reactions of the lithium salt of the ligand with the corresponding halides. X-ray structural and elemental analysis showed that 3, 4, and 5 are neutral, monomeric and solvent-free complexes. These complexes adopt a pseudo-octahedral geometry with the two X (X=Cl, Br, BH4) arranged in the trans positions.

Molecular Aluminophosphonate: Model Compound for the Isoelectronic Double‐Six‐Ring (D6R) Secondary Building Unit of Zeolites

The reaction of tert-butylphosphonic acid with equimolar quantities of AlMe3 in THF/n-hexane yields a mixture of [MeAlO3PtBu]6 (1) and [MeAlO3PtBu]4 (2). The molecular structure of 1 resembles the D6R building units found in aluminophosphates. The central core of the Al6O18P6 polyhedron can be described as a cylindrical drum. By tailoring the alkyl groups on aluminum and phosphorus, it is possible to generate bigger building units of aluminophosphate molecular sieves.

Monomere Organosamarium(III) Chalkogenolate durch reduktive Spaltung von E–E-Bindungen (E = S, Se, Te)

Abstract The THF adduct of decamethylsamarocene, CP ★ 2 Sm(THF) 2 , reacts with disulfides, diselenides and ditellurides to give organosamarium(III) complexes containing a SmE bond (E = S, Se, Te). The molecular structures of the complexes CP ★ 2 Sm(S 2 CNMe 2 ) ( 1 ), Cp ★ 2 Sm[TeC 6 H 2 Me 3 -2,4,6](THF) ( 4 ) and Cp ★ 2 Sm[SeC 6 H 2 (CF 3 ) 3 -2,4,6](THF) ( 5 have been determined by X-ray diffraction.

A Functionalized Heterocubane with Extensive Intermolecular Hydrogen Bonds

A unique three-dimensional assembly is evident in the crystal structure of the cage compound 1: each molecule participates in the formation of eight O-H⋅⋅⋅O hydrogen bonds with neighboring molecules to form cavities with approximate dimensions of 3×3×8 Å3 . In contrast, compound 2, which contains the same framework structure, does not show this behavior in the crystal.

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.

Cyclooctatetraenyl complexes of the early transition metals and lanthanides: Part XII. New sandwich and half-sandwich complexes of the lanthanides containing cyclooctatetraenyl ligands

Abstract The crystal structure of [(COT)Ce(μ-O 3 SCF 3 )(THF) 2 ] 2 ( 1 ) (COT=η 8 -C 8 H 8 ) has been determined by X-ray diffraction. The compound crystallizes in the triclinic space group P 1 ( a =930.7(4), b =1274.4(7), c =1864.1(10) pm; α =97.68(6), β =101.01(2), γ =105.25(1)°; Z =2). Together with the bridging triflate ligands the cerium atoms form an eight-membered Ce 2 O 4 S 2 ring. Treatment of 1 with 2 equiv. of K[1,3- t Bu 2 C 5 H 3 ] affords the mixed-sandwich complex (COT)Ce(η 5 -1,3- t Bu 2 C 5 H 3 ) ( 2 ) in 78% yield. Furthermore, the preparation of a series of new lanthanide half-sandwich complexes containing the 1,4-bis(trimethylsilyl)cyclooctatetraenyl ligand (=COT″) and additional heteroallylic, aryloxide, and alkyl ligands is reported.

Synthese, Struktur und Eigenschaften von [nacnac]MX3‐Verbindungen (M = Ge, Sn; X = Cl, Br, I)

Umsetzungen von [(2,6-iPr2C6H3)NC(Me)C(H)C(Me)N(2,6-iPr2C6H3)]Li ([nacnac]Li) (1) mit SnX4 (X = Cl, Br, I) und GeCl4 in Et2O ergaben durch einfache Substitution Metallacyclen mit teilweise unterschiedlichem strukturellem Aufbau. In den [nacnac]SnX3-Verbindungen (X = Cl 2, Br 3, I 4) ist das Zinnatom funffach koordiniert und ist Teil eines sechsgliedrigen Ringes. Die Sn–NBindungslange betragt 2.163(4) A in 3 und in 4 2.176(5) A. Das funffach koordinierte Germaniumatom der [nacnac]GeCl3-Verbindung 5 weist zusatzlich zu den drei Chloratomen eine Bindung zu einem Kohlenstoff- und eine Bindung zu einem Stickstoffatom auf. Im Gegensatz zu den bisher bekannten Verbindungen mit dem [nacnac]-Liganden fuhrt diese Reaktion zur Bildung einer Metall–Kohlenstoff-Bindung (1.971(3) A) und zu einem viergliedrigen Ring. Die Ge–NBindungslange (2.419(2) A) weist auf eine schwach koordinierende Bindung hin. Synthesis, Structure, and Properties of [nacnac]MX3 Compounds (M = Ge, Sn; X = Cl, Br, I) Reactions of [nacnac]Li [(2,6-iPr2C6H3)NC(Me)C(H)C(Me)N(2,6-iPr2C6H3)]Li (1) with SnX4 (X = Cl, Br, I) and GeCl4 in Et2O resulted in metallacyclic compounds with different structural moieties. In the [nacnac]SnX3 compounds (X = Cl 2, Br 3, I 4) the tin atom is five coordinated and part of a six-membered ring. The Sn–N-bond length of 3 is 2.163(4) A and 2.176(5) A of 4. The five coordinated germanium of the [nacnac]GeCl3 compound 5 shows in addition to the three chlorine atoms further bonds to a carbon and to a nitrogen atom. In contrast to the known compounds with the [nacnac] ligand the afore mentioned reaction creates a carbon–metal-bond (1.971(3) A) forming a four-membered ring. The Ge–N bond length (2.419(2) A) indicates the formation of a weakly coordinating bond.