The copolymerization of ethylene and 1-hexene with a variety of unbridged indenylmetallocenes was investigated and compared to unbridged bis(indenyl)zirconium dichloride and bis(cyclopentadienyl)zirconium dichloride as well as ansa-bridged rac-ethylenebis(indenyl)zirconium dichloride (EBIZrCl 2). The unbridged bis(2-phenylindenyl)zirconium dichloride showed higher selectivity for the incorporation of 1-hexene than the bridged rac-ethylenebis(indenyl)zirconium dichloride and much higher 1-hexene incoporation than the unbridged bis(indenyl)zirconium dichloride and bis(cyclopentadienyl)zirconium dichloride. Both ligands appear to be important since the 1-hexene incorporation of the mixed ligand compound (cyclopentadienyl)(2-phenylindenyl)zirconium dichloride is much lower than that of bis-(2-phenylindenyl)zirconium dichloride. For unbridged bis(indenyl)metallocenes, the nature of the substituent in the 2-position plays an important role in comonomer selectivity: bis(2-methylindenyl)zirconium dichloride and bis(2-phenylethynylindenyl)zirconium dichloride exhibit much higher 1-hexene incorporation than bis(indenyl)zirconium dichloride but lower than bis(2-phenylindenyl)zirconium dichloride.

Five amine bis(phenolate)zirconium dibenzyl complexes, [ONDO]ZrBn2, were investigated in ethylene/1-hexene copolymerization. The copolymerization behavior is sensitive both to the symmetry and connectivity of the ligand framework and to the nature of the cocatalyst. The C s-symmetric [ONDO]-ZrBn2 complexes were more active and exhibited higher comonomer incorporations than the C2-symmetric [ONDO]ZrBn2 complexes. The nature of the cocatalyst was observed to have a significant effect on the amount of hexene incorporated into the copolymers. Activation of the Cs-symmetric [ONDO]ZrBn2 complexes with MMAO yielded copolymers with 10% higher hexene incorporation than that observed upon activation with [PhNMe2H][B(C6F5)4], [B(C6F5)3], or [Ph3C][B(C6F5)4].

The reaction of diaminomaleonitrile (DAMN) with aldehydes such as acrolein, methacrolein, and crotonaldehyde in the presence of acid catalyst at low temperature yielded exclusively monoimine derivatives of DAMN. These compounds have very low loss of volatiles up to 1000 °C and form high char yields. The residual mass at 800 °C for the acrolein derivative was found to equal 70% of the starting material. Thermally induced step growth 1,4-conjugate addition polymerization on these compounds yields moderate molecular weight oligomeric materials (M n = 1376, M w = 2050). N-EthylDAMN was synthesized by reaction of DAMN with acetaldehyde followed by reduction with NaBH4. N-EthylDAMN reacted with acrolein, methacrolein, and crotonaldehyde to form N-ethyl-monoimine derivatives of DAMN. These analogues also undergo 1,4-conjugate addition polymerization to yield linear polymers. The dimethylamino derivative was found to undergo polymerization by a different mechanism, strengthening the proposed 1,4-conjugate addition mechanism.

A series of C1 symmetric, 1,2′-bridged bis(indenyl)zirconium dichlorides were prepared to study the effect of ligand substitution, symmetry, and bridge identity on the stereoselectivity of propylene polymerization. Unsubstituted [1-(1-indenyl)-2-(2-indenyl)ethane]zirconium dichloride, Et(2-Ind)(1-Ind)-ZrCl 2 (1), was synthesized, and its propylene polymerization behavior was compared to three 2-phenylsubstituted complexes with different bridges: (4). The polymerization activity, polypropylene molecular weight, and microstructure were dependent upon the identity of the bridge and the substitution patterns on the metallocenes . Metallocenes 1, 2, 3, and 4 are characterized by a gauche orientation of the indenyl ligands, in contrast to the anti or syn orientation of 1,1′-bridged ansa-bis(indenyl)metallocenes. The gauche metallocene 3 yields a polypropylene of intermediate isotacticity ([mmmm] ) 58%) when compared to the C 2 symmetric anti-Me2Si(2-phenyl-1-indenyl)2ZrCl2 ([mmmm] ) 86%) and the Cs symmetric synMe2Si(2-phenyl-1-indenyl)2ZrCl2 ([mmmm] ) 7%). The gauche metallocene 2 yielded the most highly isotactic polypropylene ([mmmm] ) 74%). Analysis of the sequence distributions of the polypropylenes derived from metallocenes 1-4 reveals a predominance of [mrrm] stereoerrors. The high stereoselectivity of the bridged metallocenes 1-4 implies that gauche conformations may be responsible for some of the higher tacticity fractions observed in polypropylenes derived from the unbridged 2-arylindene metallocenes.