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Five new indenyl zirconium metallocenes with 2-alkyl and 2-aryl substituents were synthesized and characterized. For the synthesis of the ligand the di-Grignard reagent 1,2-bis(magnesiomethyl)benzene dichloride was explored as a synthon to 2-substituted indenes. This procedure provides access to a variety of functionalized 2-indenylmetallocenes such as bis(2-ferrocenylindene)zirconium dichloride and bis(2-adamantylindenyl)zirconium dichloride. Crystallographic characterization of bis[2-(4-(dimethylamino)phenyl)indenyl] zirconium dichloride revealed an anti conformation with a coplanar orientation of the dimethylamino substituent to the aryl ring in the solid state. The polymerization behavior of all five zirconocene dichlorides in liquid propylene was studied in the presence of MAO at various temperatures, and the results were compared to those for the known catalyst system bis(2-phenylindenyl)zirconium dichloride/MAO (M1/MAO). The productivity of the 2-arylindene metallocenes in propylene polymerization was on the order of 100−7000 kg of PP/((mol of Zr) h). In contrast, the (2-adamantylindenyl)metallocenes exhibited very low productivities of 6 kg PP/((mol of Zr) h) in propylene polymerization.

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Bis(2-arylindenyl)zirconium dichlorides activated by methylaluminoxane produce elastomeric polypropylene with a stereoblock microstructure. In an effort to experimentally explore the importance of the 2-arylindene ligand in producing these materials, a series of catalysts was investigated that differed significantly from the parent ligand architecture. In particular, we sought to examine the influence of ligand aryl stacking on the polymerization behavior of these metallocenes. We discovered that the bis(2-arylindenyl) framework is important for the production of elastomeric polypropylene by this type of unbridged complex. Small changes in the fundamental catalyst structure upset the delicate balance between ligand rotation and monomer insertion resulting in the production of amorphous polymers.

Oxo-bridged clusters of manganese1•* 12 have been shown to occur in the active sites of the catalases, /weudocatalases, ribonucleotide reductases, and the photosynthetic water oxidation center. The synthetic complexes with structural units { 2(µ-0)(µ-02-CCH3)2}2+3"5 and { (µ-0)2(µ-02€€ 3)}2+ 6•7 are of current interest since they are good models for these enzymes.It has been shown3 4•48•6•6*•8 that ^-oxo)bis^-acetato)dimanganese-(III) complexes could be oxidized by following two pathways:(i) sequential electrochemical oxidation to MnmMnIV and MnIV2 oxidation levels and (ii) chemical transformations to {Mnm-(µ-0)(µ-)2}3+ and { (µ-0)2(µ-3 )}2+ species. It is interesting to note that while disproportionation of the {Mn111-(µ-0)2}3+ core under acidic conditions has been postulated previously,9•10 *11to our knowledge isolation of a 2(µ-0)(µac)2}2+ species from a { (µ-0)2(µ-)}2+ species has not so far been achieved.We recently reported7 an antiferromagnetically coupled dimanganese complex [ (µ-)2(µ-20 6)( ߣ.)2] (Cl-04)2• 20 (1) using MeL as a facially capping ligand [MeL = f Dedicated to Professor Richard H. Holm on the occasion of his 60th