Insights into functional-group-tolerant polymerization catalysis with phosphine-sulfonamide palladium (II) complexes
Type
ArticleAuthors
Jian, ZhongbaoFalivene, Laura

Wucher, Philipp
Roesle, Philipp
Caporaso, Lucia

Cavallo, Luigi

Gçttker-Schnetmann, Inigo
Mecking, Stefan
KAUST Department
Chemical Science ProgramKAUST Catalysis Center (KCC)
Physical Science and Engineering (PSE) Division
Date
2014-12-09Online Publication Date
2014-12-08Print Publication Date
2015-01-26Embargo End Date
2015-12-09Permanent link to this record
http://hdl.handle.net/10754/563915
Metadata
Show full item recordAbstract
Two series of cationic palladium(II) methyl complexes {[(2-MeOC6H4)2PC6H4SO2NHC6H3(2,6-R1,R2)]PdMe}2[A]2 (X1+-A: R1=R2=H: H1+-A; R1=R2=CH(CH3)2: DIPP1+-A; R1=H, R2=CF3: CF31+-A; A=BF4 or SbF6) and neutral palladium(II) methyl complexes {[(2-MeOC6H4)2PC6H4SO2NC6H3(2,6-R1,R2)]PdMe(L)} (X1-acetone: L=acetone; X1-dmso: L=dimethyl sulfoxide; X1-pyr: L=pyridine) chelated by a phosphine-sulfonamide were synthesized and fully characterized. Stoichiometric insertion of methyl acrylate (MA) into all complexes revealed that a 2,1 regiochemistry dominates in the first insertion of MA. Subsequently, for the cationic complexes X1+-A, β-H elimination from the 2,1-insertion product X2+-AMA-2,1 is overwhelmingly favored over a second MA insertion to yield two major products X4+-AMA-1,2 and X5+-AMA. By contrast, for the weakly coordinated neutral complexes X1-acetone and X1-dmso, a second MA insertion of the 2,1-insertion product X2MA-2,1 is faster than β-H elimination and gives X3MA as major products. For the strongly coordinated neutral complexes X1-pyr, no second MA insertion and no β-H elimination (except for DIPP2-pyrMA-2,1) were observed for the 2,1-insertion product X2-pyrMA-2,1. The cationic complexes X1+-A exhibited high catalytic activities for ethylene dimerization, affording butenes (C4) with a high selectivity of up to 97.7% (1-butene: 99.3%). Differences in activities and selectivities suggest that the phosphine-sulfonamide ligands remain coordinated to the metal center in a bidentate fashion in the catalytically active species. By comparison, the neutral complexes X1-acetone, X1-dmso, and X1-pyr showed very low activity towards ethylene to give traces of oligomers. DFT analyses taking into account the two possible coordination modes (O or N) of the sulfonamide ligand for the cationic system CF31+ suggested that the experimentally observed high activity in ethylene dimerization is the result of a facile first ethylene insertion into the O-coordinated PdMe isomer and a subsequent favored β-H elimination from the N-coordinated isomer formed by isomerization of the insertion product. Steric hindrance by the N-aryl substituent in the neutral systems CF31 and H1 appears to contribute significantly to a higher barrier of insertion, which accounts for the experimentally observed low activity towards ethylene oligomerization. Coordination switch: Analysis and comparison of the reactivity of new neutral and cationic PdII phosphine-sulfonamide complexes towards olefins in stoichiometric insertion and pressure-reactor experiments, complemented by DFT studies, elucidated the decisive factors for their catalytic behavior, including N versus O coordination modes (see figure).Sponsors
Z.J. is grateful to the Alexander von Humboldt Foundation for a postdoctoral research fellowship and to the University of Konstanz for a EU FP7 Marie Curie Zukunftskolleg Incoming Fellowship Programme (grant no. 291784).Publisher
WileyJournal
Chemistry - A European JournalRelations
Is Supplemented By:- [Dataset]
Jian, Z., Falivene, L., Wucher, P., Roesle, P., Caporaso, L., Cavallo, L., … Mecking, S. (2014). CCDC 973617: Experimental Crystal Structure Determination [Data set]. Cambridge Crystallographic Data Centre. https://doi.org/10.5517/cc11p40w. DOI: 10.5517/cc11p40w HANDLE: 10754/624288 - [Dataset]
Jian, Z., Falivene, L., Wucher, P., Roesle, P., Caporaso, L., Cavallo, L., … Mecking, S. (2014). CCDC 973618: Experimental Crystal Structure Determination [Data set]. Cambridge Crystallographic Data Centre. https://doi.org/10.5517/cc11p41x. DOI: 10.5517/cc11p41x HANDLE: 10754/624289 - [Dataset]
Jian, Z., Falivene, L., Wucher, P., Roesle, P., Caporaso, L., Cavallo, L., … Mecking, S. (2014). CCDC 973619: Experimental Crystal Structure Determination [Data set]. Cambridge Crystallographic Data Centre. https://doi.org/10.5517/cc11p42y. DOI: 10.5517/cc11p42y HANDLE: 10754/624290 - [Dataset]
Jian, Z., Falivene, L., Wucher, P., Roesle, P., Caporaso, L., Cavallo, L., … Mecking, S. (2014). CCDC 973620: Experimental Crystal Structure Determination [Data set]. Cambridge Crystallographic Data Centre. https://doi.org/10.5517/cc11p43z. DOI: 10.5517/cc11p43z HANDLE: 10754/624291 - [Dataset]
Jian, Z., Falivene, L., Wucher, P., Roesle, P., Caporaso, L., Cavallo, L., … Mecking, S. (2014). CCDC 973621: Experimental Crystal Structure Determination [Data set]. Cambridge Crystallographic Data Centre. https://doi.org/10.5517/cc11p440. DOI: 10.5517/cc11p440 HANDLE: 10754/624292 - [Dataset]
Jian, Z., Falivene, L., Wucher, P., Roesle, P., Caporaso, L., Cavallo, L., … Mecking, S. (2014). CCDC 973622: Experimental Crystal Structure Determination [Data set]. Cambridge Crystallographic Data Centre. https://doi.org/10.5517/cc11p451. DOI: 10.5517/cc11p451 HANDLE: 10754/624293 - [Dataset]
Jian, Z., Falivene, L., Wucher, P., Roesle, P., Caporaso, L., Cavallo, L., … Mecking, S. (2014). CCDC 977700: Experimental Crystal Structure Determination [Data set]. Cambridge Crystallographic Data Centre. https://doi.org/10.5517/cc11tcqy. DOI: 10.5517/cc11tcqy HANDLE: 10754/624299 - [Dataset]
Jian, Z., Falivene, L., Wucher, P., Roesle, P., Caporaso, L., Cavallo, L., … Mecking, S. (2014). CCDC 977701: Experimental Crystal Structure Determination [Data set]. Cambridge Crystallographic Data Centre. https://doi.org/10.5517/cc11tcrz. DOI: 10.5517/cc11tcrz HANDLE: 10754/624300
ae974a485f413a2113503eed53cd6c53
10.1002/chem.201404856