Kinetic Study of the Insertion of Norbornadiene into Palladium−Carbon Bonds of Complexes Containing the Rigid Bidentate Nitrogen Ligand Bis(arylimino)acenaphthene

Abstract

Kinetic study of the insertion of norbornadiene into palladium-carbon bonds of complexes containing the rigid bidentate nitrogen ligand Bis(arylimino)acenaphtene Groen, J.H.; Delis, J.G.P.; van Leeuwen, P.W.N.M.; Vrieze, K. Published in: Organometallics DOI:10.1021/om960789fLink to publication Citation for published version (APA):Groen, J. H., Delis, J. G. P., van Leeuwen, P. W. N. M., & Vrieze, K. (1997). Kinetic study of the insertion of norbornadiene into palladium-carbon bonds of complexes containing the rigid bidentate nitrogen ligand Bis(arylimino)acenaphtene. Organometallics, 16, 68-77. DOI: 10.1021/om960789f General rightsIt is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), other than for strictly personal, individual use, unless the work is under an open content license (like Creative Commons). Disclaimer/Complaints regulationsIf you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: http://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. complexes (1b-12b), bearing the bidentate nitrogen ligand bis(arylimino)acenaphthene (Ar-BIAN), have been synthesized via reaction of the corresponding neutral acylpalladium complexes Pd(C(O)R)X(Ar-BIAN) (1a-12a) with norbornadiene (nbd). For the first time, an extensive kinetic study of this migratory alkene insertion into acyl-palladium bonds of neutral complexes containing R-diimine ligands has been carried out. It has been found that under pseudo-first-order circumstances these reactions follow the rate law k obsd ) k 1 + k 2 [nbd], which shows that these reactions proceed via a pathway independent of alkene concentration (k 1 pathway) and a pathway dependent on alkene concentration (k 2 pathway). The dramatic decrease of the rate constants k 1 and k 2 upon increasing the steric bulk of the BIAN ligand and the large negative entropy of activation and low enthalpy of activation for both pathways indicate that the k 1 and k 2 pathways are closely related and involve associative processes. From the influence of solvent, X and C(O)R ligand, steric and electronic properties of the BIAN ligand, the presence of free halide and free BIAN, and the parameters of activation, mechanisms have been proposed for both pathways. The k 1 pathway may proceed via a rate-determining solvent-assisted halide or nitrogen dissociation, followed by alkene association and migratory insertion, while the k 2 pathway may occur via a rate-determining migratory alkene insertion in a contact ion pair intermediate. This species may be formed via alkene association followed by either halide or nitrogen dissociation.

Low‐Temperature Kinetic NMR Studies on the Insertion of a Single Olefin Molecule into a ZrC Bond: Assessing the Counterion–Solvent Interplay

“…A smaller amount of energy is required to displace the B(C 6 F 5 ) 4 À anion from the first coordination sphere but, because of the fact that the degrees of mobility of B(C 6 F 5 ) 4 À are similar in ISIPs and OSIPs, the recovery of entropy is smaller and approaches the typical value of DS°of an associative bimolecular process occurring in low polar solvents (around À50 cal mol À1 K À1 ). [36][37][38][39] Notably, almost the same recovery of entropy (DS°= À44 AE 5 cal mol À1 K À1 ) was observed for the sole olefin polymerization catalyst with the MeB(C 6 F 5 ) 3 À counterion in the second coordination sphere. [29] The insertion of 2 in 1a and 1b is around 3-5 and 50-100 times slower, respectively, in [D 8 ]toluene/[D 5 ]chlorobenzene than in [D 8 ]toluene (DDG°= 0.5-1.0 and 2.2-2.5 kcal mol À1 for 1a and 1b, respectively) and the anion has no effect on the insertion rate (Table 1, entries 9-16).…”

Synthesis, Characterization, and Protonation Reactions of Ar‐BIAN and Ar‐BICAT Diimine Platinum Diphenyl Complexes

“…[46] The Ar-BIAN system is a highly stable, rigid bidentate spectator ligand with interesting electronic properties. [47,48] Elsevier and co-workers suggested that Ar-BIAN ligands may act as stronger σ-donors toward the metal when compared to bpy, and also proposed that the rigid Ar-BIAN ligands are rather comparable to open chain R-DAB analogues in electronic properties, which would be the case if the diimine system in the Ar-BIAN ligands is electronically isolated from and has no conjugation with the naphthalene backbone.…”

Preparation and structural characterization of tetracoordinated tungsten(II) diazadiene complexes

“…As a result, the reaction chemistry of this class of diimine ligand with a variety of transition metals has become well established [1,[3][4][5][6][7][8]. Lately, the interest in early transition metal chemistry has focused on group 6 complexes that contain chelating diazadiene ligands [9][10][11][12][13][14][15].…”