Binuclear Pd-methyl complexes of N,N′-{1, n}-alkanediyl- bis(pyridinyl-2-methanimine) ligands (n = 5, 8, 9, 10 and 12): Evaluation as catalysts precursors for phenylacetylene polymerization
Department of Chemistry, University of the Western Cape, Bellville, South Africa; Department of Chemistry and Polymer Science, Stellenbosch University, Private Bag 1, Matieland, 7601, Stellenbosch, South Africa
Sibanyoni, J.M., Department of Chemistry, University of the Western Cape, Bellville, South Africa; Bagihalli, G.B., Department of Chemistry and Polymer Science, Stellenbosch University, Private Bag 1, Matieland, 7601, Stellenbosch, South Africa; Mapolie, S.F., Department of Chemistry and Polymer Science, Stellenbosch University, Private Bag 1, Matieland, 7601, Stellenbosch, South Africa
A series of bifunctional ligands of the type N,N′-{1, n}-alkanediyl-bis(pyridinyl-2-methanimine) {n = 5, 8, 9, 10, 12}(L1-L5) were synthesized and fully characterized by IR, 1H NMR, and 13C NMR spectroscopy. Binuclear palladium-methylchloride complexes C1-C5 were formed by reacting the ligands with [(COD)Pd(CH 3)Cl]. The formed complexes were fully characterized by IR, 1H NMR, 13C NMR, spectroscopy, electrospray ionization mass spectrometry and elemental analysis. The synthesized complexes were evaluated as catalyst precursors for phenylacetylene polymerization after activation with AgBF 4, AgBPh 4 and NaB(Ar f) 4 (Sodium tetrakis[(3.5-trifluoromethyl)phenyl]borate) under various reaction conditions (solvent ratio, catalyst type, monomer/catalyst ratio, reaction time and nature of counterion). The cationic palladium-methyl catalyst precursors C1a-C5a were found to be active catalysts for phenylacetylene polymerization. The obtained polyphenylacetylene were analyzed by IR, 1H NMR and 13C NMR spectroscopy and gel permeation chromatography (GPC) and found to be largely cis-transoidal in nature. © 2011 Elsevier B.V. All rights reserved.
Diimine complexes; N,N′-{1,n}-alkanediyl-bis(pyridinyl-2-methanimine) ligands; Pd-methyl complexes; Phenylacetylene polymerization; Polyphenylacetylene
Active catalyst; Bifunctional ligand; Catalyst precursors; Catalysts precursors; Counterions; Diimine complexes; Electrospray ionization mass spectrometry; Pd-methyl complexes; Phenylacetylenes; Polyphenylacetylene; Reaction conditions; Tetrakis; Trifluoromethyl; Acetylene; Aromatic hydrocarbons; Catalysts; Cationic polymerization; Chlorine compounds; Electrospray ionization; Gel permeation chromatography; Ligands; Mass spectrometry; Nuclear magnetic resonance spectroscopy; Organic polymers; Palladium compounds