High-temperature catalysts for the production of α-olefins based on iron(II) and iron(III) tridentate bis(imino)pyridine complexes modified by nitrilo group

• Published in: Journal of polymer science. Part A, Polymer chemistry Vol. 46; no. 2; pp. 585 - 611
• Main Authors: Ionkin, Alex S, Marshall, William J, Adelman, Douglas J, Fones, Barbara Bobik, Fish, Brian M, Schiffhauer, Matthew F, Soper, Paul D, Waterland, Robert L, Spence, Rupert E, Xie, Tuyu
• Format: Journal Article
• Language: English
• Published: Wiley Subscription Services, Inc., A Wiley Company 15.01.2008
• ISSN: 0887-624X; 1099-0518
• DOI: 10.1002/pola.22408

Series of Fe(II) and Fe(III) tridentate bis(imino)pyridine complexes without nitrilo groups 2-6 and with nitrilo groups 7-13 were synthesized. According to X-ray analysis, the introduction of nitrilo groups in para- and ortho-positions tends to result in shorter axial Fe---N bonds. Both types of complexes, 2-6 and 9-13, afforded very productive catalysts for the production of α-olefins with higher K values and better linearity of Schultz-Flory distribution α-olefins than the parent methyl substituted Fe(II) complex 1. Noticeably, the complexes functionalized with a para-nitrilo group 9-13 tend to make α-olefins with higher K values of the Schultz-Flory distribution, more ideal distributions, and less of the heavier insoluble fractions of α-olefins than corresponding nonsymmetrically substituted complexes without para-nitrilo groups 2-6. Statistically significant correlations were obtained between % solids of total α-olefins and the blocked solid angle fraction in the +z hemisphere ($ R_{{\rm adj}}^2 $= 51.3%, p = 0.012) and between catalyst productivity and total blocked solid angle fraction ($ R_{{\rm adj}}^2 $= 43.5%, p = 0.023). The modest values of $ R_{{\rm adj}}^2 $show that, while steric effects are significant, they are not the sole factor determining catalyst performance. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 585-611, 2008