title: Anion exchange in [Ni(η(5)-C(5)H(4)R)(Cl)(NHC)]. Counterion effect on the structure and catalytic activity.
abstract: A series of novel complexes [Ni(η(5)-C5H4R)(L)(NHC)](+)A(-)2a-2j and [Ni(η(5)-C5H5)(A)(NHC)] 3a-3c has been obtained by anion metathesis from the corresponding chlorides 1a-1d, depending on the anion binding properties and reaction conditions. Solid-state structures of two cationic complexes (2c, 2j) and two complexes with a coordinated anion (3a, 3c) have been determined by X-ray diffraction revealing a trigonal planar geometry in all cases. Unexpectedly, 3c displayed unprecedented for this type of compounds temperature-dependent NMR spectra that were interpreted in terms of spin equilibrium. The cationic complexes 2 were less efficient in styrene polymerization than the parent chlorides 1. However, the activity of 2 and 3 in Suzuki cross-coupling did not depend considerably on the counterion.
authors.affiliation: Warsaw University of Technology, Faculty of Chemistry, Noakowskiego 3, 00-664 Warsaw, Poland. wbuch@ch.pw.edu.pl.
authors.forename: Włodzimierz
authors.initials: W
authors.lastname: Buchowicz
authors.forename: Łukasz
authors.initials: Ł
authors.lastname: Banach
authors.forename: Joanna
authors.initials: J
authors.lastname: Conder
authors.forename: Piotr A
authors.initials: PA
authors.lastname: Guńka
authors.forename: Dominik
authors.initials: D
authors.lastname: Kubicki
authors.forename: Piotr
authors.initials: P
authors.lastname: Buchalski