title: Structure of zirconocene complexes relevant for olefin catalysis: infrared fingerprint of the Zr(C(5)H(5))(2)(OH)(CH(3)CN)(+) cation in the gas phase.
abstract: Cationic zirconocene complexes are active species in Ziegler-Natta catalysis for olefin polymerization. Their structure and metal-ligand bond strength strongly influence their activity. In the present work, the infrared multiphoton dissociation (IRMPD) spectrum of mass selected Zr(C(5)H(5))(2)(OH)(CH(3)CN)(+) cations was obtained in the 300-1500 cm(-1) fingerprint range by coupling a Fourier-transform ion cyclotron resonance (FT-ICR) mass spectrometer equipped with an electrospray ionization (ESI) source and the infrared free electron laser (IR-FEL) at the Centre Laser Infrarouge d'Orsay (CLIO). The experimental efforts are complemented by quantum chemical calculations at the MP2 and B3LYP levels using the 6-311G* basis set. Vibrational assignments of transitions observed in the IRMPD spectra to modes of the Zr-O-H, C(5)H(5), and CH(3)CN moieties are based on comparison to calculated linear absorption spectra. Both the experimental data and the calculations provide unprecedented information about structure, metal-ligand bonding, charge distribution, and binding energy of the complex.
authors.affiliation: Institut für Optik und Atomare Physik, Technische Universität Berlin, Hardenbergstrasse 36, 10623 Berlin, Germany.
authors.forename: Anita
authors.initials: A
authors.lastname: Lagutschenkov
authors.forename: Andreas
authors.initials: A
authors.lastname: Springer
authors.forename: Ulrich Joseph
authors.initials: UJ
authors.lastname: Lorenz
authors.forename: Philippe
authors.initials: P
authors.lastname: Maitre
authors.forename: Otto
authors.initials: O
authors.lastname: Dopfer
mesh_terms: D000475:Alkenes / Q000737:chemistry*; D002384:Catalysis; D002412:Cations / Q000737:chemistry; D003198:Computer Simulation; D005740:Gases / Q000737:chemistry; D008024:Ligands; D008956:Models, Chemical; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000737:chemistry*; D011789:Quantum Theory; D014732:Vibration; D015040:Zirconium / Q000737:chemistry*
chemical_list: D000475:Alkenes; D002412:Cations; D005740:Gases; D008024:Ligands; D009942:Organometallic Compounds; C023398:Zirconocene dichloride; D015040:Zirconium