The sulfide-linked bis(phenol) tbmpH2 (tbmp = 2,2‘-thiobis(6-tert-butyl-4-methylphenolato)) gives a series of titanium complexes of the formula [Ti(tbmp)X2]2 or [Ti(tbmp)(L)X2] (L = two-electron ligand, X = one-electron ligand). The molecular structures of [Ti(tbmp)(OiPr)2]2 and of [Ti(tbmp){C6H4(CH2NMe2)-2}Cl] were determined by single-crystal X-ray structural analyses. An unusually long titanium−sulfur bond of ∼270 pm is observed in both complexes which contain a six-coordinate titanium center. Variable-temperature NMR spectroscopy shows a fluxional coordination of the chelating aryl group in [Ti(tbmp){C6H4(CH2NMe2)-2}Cl].

A series of new titanium complexes of the general type Ti(mbmp)X2 (X = Br, I; OMe, OiPr, OtBu), containing a bidentate bis(phenoxy) ligand derived from 2,2'-methylenebis(6-tert-butyl-4-methylphenol) (mbmpH2), was prepared. The 'H-chemical shifts for the protons of the methylene link were found to vary considerably as a function of the ligand X. Reaction of Ti(OiPr)4 with two equivalents of mbmpH2 gave the C2-symmetric spiro-titanate complex Ti(mbmp)2.The crystalline labile solvent adducts of the dichloro complex Ti(mbmp)C12 with THF and DME were isolated and characterized. A single-crystal X-ray structural analysis revealed the THF adduct to be a mono(THF) adduct with a trigonalbipyramidal configuration, the bidentate mbmp ligand spanning an apical and equatorial site and the THF ligand occupying the remaining apical position.Mononuclear titanium complexes Ti(OR)2X2 [(OR), = 2,2'-methylenebis(6-tert-butyl-4-methylphenoxy) (mbmp); 2,2'-thiobis(6-tert-butyl-4-methylphenoxy) (tbmp); X = CI, OiPr] containing bidentate phenoxy ligands derived from the sterically demanding bis(pheno1s) mbmpH2 and tbmpH2 have been reported to polymerize 1 -alkenes, styrene, and 1,3-dienes when activated with methylaluminoxane These soluble titanium phenoxy complexes constitute a new class of homogeneous polymerization catalysts distinct from the well-known ansa-metallocene systems that contain two cyclopentadienyl ligands linked by a covalent bridge (Brintzinger-type ligands). In order to rationally control activity, stereoselectivity, and copolymerization behavior of catalysts based on such bidentate phenoxy ligands, detailed information about the coordination sphere around the titanium center is required. To date, however, only a limited number of transition metal complexes containing the mbmp ligand have been doc~mented[~,~I. Mononuclear titanium complexes of the formula Ti(mbmp)X, with X = Cl, Me, q3-BH4, and X2 = (q5-C5H5)C1 were reported to display a C,-symmetric structure in the solid state with a strongly puckered eight-membered chelate ring in a boat conformati~n[~I. The 'H-NMR chemical shifts for the two methylene protons of the bridge was found to vary considerably as a function of the ligand X, although their relationship with the various conformations of the eight-membered metallacycle remained undefinedL5I. In order to obtain more detailed information about the ligand environment of the Ti(mbmp) fragment, we attempted to augment the number of complexes in this series by preparing mbmp complexes previously not described. We report here that the mbmp ligand forms besides mono(1igand) titanium complexes of the general formula Ti(mbmp)X2(L) (X = anionic ligand, L = two-electron ligand) also a mononuclear bis(1igand) complex (mbmp),Ti with a spirotitanate structure. Results and DiscussionWhen the easily prepared orange-red dichloro complex Ti(mbmp)C12[31 is treated with halotrimethylsilane Me3SiX (X = Br, I) in hexane for 3 d, the corresponding red-brown dibromo and dark red diiodo derivatives Ti(mbmp)X2 (X = Br, I) are cleanly...

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Die Phosphaniminato‐Komplexe [MCl(NPEt3)]4 mit M = Mangan und Nickel sowie [MnBr(NPEt3)]4 entstehen durch Schmelzreaktion aus den wasserfreien Halogeniden MX2 und überschüssigem Phosphanimin Me3SiNPEt3. Sie bilden paramagnetische, feuchtigkeitsempfindliche, orange (M = Mn) bzw. türkisgrüne (M = Ni) Kristalle, die wir IR‐spektroskopisch und durch Kristallstrukturanalysen charakterisiert haben. [MnCl(NPEt3)]4 (1): Raumgruppe C2/c, Z = 4, Strukturlösung mit 3 591 unabhängigen Reflexen, (2811 > 2σ(I)) R = 0,036. Gitterkonstanten bei −50°C: a = 2104,3; b = 1100,6; c = 1966,5 pm, β = 115,87°. [NiCl(NPEt3)]4 (2): Raumgruppe C2/c, Z = 4, Strukturlösung mit 2 771 unabhängigen Reflexen, (1 611 > 2σ(I)) R = 0,056. Gitterkonstanten bei −50°C: a = 2051,6; b = 1 099,2; c = 1954,6 pm, β = 115,80°. 1 und 2 sind miteinander isotyp. Sie bilden Heterocuban‐Strukturen, in denen die Metallatome über μ3‐N‐Brücken der Phosphaniminato‐Gruppen verknüpft sind mit M4N4‐Brückenbindungswinkeln nahe bei 90°.

Two new titanium complexes of the general type Ti(q5:q1-function of the temperature, indicating the presence of a n C5H4SiMe,NCH,CH2X)C12 (X = NMe,, OMe), containing a equilibrium between the tri-and bidentate bonding mode tridentate ligand, were prepared by reaction of Ti(q5-C5H4Si-of the ligand. A single-crystal X-ray structural analysis of Me2C1)CI3 with the lithium amide Li(NHCH2CH2X) (X = Ti(q5 :q1-C,H4SiMe2NCH,CI-I,0Me)C12 revealed that the NMe2, OMe). The 'H-NMR chemical shifts for the protons methoxy function is not intramolecularly coordinated in the of the ethylene link were found to vary considerably as a solid state.Functionalized cyclopentadienyl liganddl] allow the synthesis of a wide variety of transition metal complexes with novel coordination spheres, which may be used in the control of the catalytic behavior of the metal center. In the context of designing new metallocene catalysts for olefin polymerization, amido-functionalized cyclopentadienyl ligands in particular have been of considerable recent interest[*]. Not only do they allow variation of the ring substituents and the nature of the bridge, which constitute common tools for the manipulation of Brintzinger-type ansa-metallocenes, but modification of the amido substit~ent[~] is also possible. In order to modulate the Lewis acidic group-4 metal center, we are studying potentially tridentate ligands by introducing an additional donor is significantly broadened at low temperatures. Despite the presumably higher Lewis acidity of the titanium center compared with that of the tetramethyl analog Ti(q5:q '-CSMe4SiMe2NCH2CH2NMe2)-Cl,['l, the dimethylamino group is apparently not more strongly coordinated [8]. On the other hand, a single-crystal structure analysis revealed that the additional donor site is unambiguously interacting with the titanium center, although considerable disorder in the CH2CH2NMe2 chain precluded an accurate solution of the Figure 1. ORTEP diagram of the molecular structure of Ti(q5:q1-C5H4SiMe2NCH2CH20Me)CI2. Thermal ellipsoids are drawn at the 50% probability level R Results and DiscussionPreviously we noted that the reaction of the dilithium derivatives Li2(C5H4SiMe2NCH2CH2X) (X = NMe2, OMe) with TiC14(THF)2, or with TiC13(THF)3 followed by oxidation, unexpectedly led to the formation of the stable C2-symmetric bis(1igand) complexes of the type Ti( q5:q'-CsH4SiMezNCH2CH2X)2[S,7a] rather than to the mono(1igand) complexes Ti(q5:q'-C5H4Si-Me2NCH2CH2X)CI2. In contrast, Ti($ :q1-C5H4SiMe2NCH2-CH2NMe2)C12 could be obtained as orange crystals in good yield by the reaction of the easily prepared Ti(q5-C5H4SiMe2CI)C13[6] with 1.33 equivalents of Li(NHCH2CH2NMe2) in toluene, followed by work-up of the reaction mixture by filtering off LiCl and the ammonium salt [NH3CH2CH2NHMe2]CI2. 'H-, I3C-NMR-spectroscopic as well as mass-spcctral and analytical data confirm the structure o f a mono(1igand) complex. However, the nature of the additional bonding site remains undefined. Variable temperature IH-NMR spectra show a fairty strong shif...