Sc(III) complexes with neutral N-3- and SNS-donor ligands - a spectroscopic study of the activation of ethene polymerisation catalysts

Scandium trichloride complexes with tridentate N3- and S2N-donor ligands (L3) have been synthesised and characterised by IR, 1H, 13C{1H} and 45Sc NMR spectroscopy, microanalysis, and solid state and solution XAFS spectroscopy. Catalytic testing of a subset of these complexes with ethene has been undertaken in chlorobenzene with MMAO-3A and PMAO-IP at 60 °C and 40 bar ethene, giving low activity ethene polymerisation. The reactions of these complexes with MeLi and AlMe3 were studied by 1H, 13C{1H}, 27Al and 45Sc NMR spectroscopy and in situ via Sc K-edge XAFS spectroscopy. Three or four mol. equivalents of MeLi react with [ScCl3(Me3-tacn)] in THF solution to form [ScMe3(Me3-tacn)] cleanly, while complexes of type [ScCl3(R-SNS)] {R-SNS = HN(CH2CH2SC10H21)2} form two different species proposed to be [ScMe3(R-SN(Li)S)] and [ScMe2(R-SN−S)]. In contrast, in situ45Sc NMR and Sc K-edge XAFS spectroscopic studies of the reaction of [ScCl3(Me3-tacn)] with 10 mol. equivalents of AlMe3 strongly suggest that alkylation at the Sc(III) centre does not occur, instead retaining the Cl3N3 coordination environment and most likely forming Sc−Cl−AlMe3 bridging interactions. Similar studies on [ScCl3(decyl-SNS)] with 10 mol. equivalents of AlMe3 are also consistent with this, indicating that alkylation at the Sc centre does not occur except in the presence of co-catalyst [Ph3C][Al{OC(CF3)3}4] and the α-alkene, hex-1-ene.     «

Scandium trichloride complexes with tridentate N3- and S2N-donor ligands (L3) have been synthesised and characterised by IR, 1H, 13C{1H} and 45Sc NMR spectroscopy, microanalysis, and solid state and solution XAFS spectroscopy. Catalytic testing of a subset of these complexes with ethene has been undertaken in chlorobenzene with MMAO-3A and PMAO-IP at 60 °C and 40 bar ethene, giving low activity ethene polymerisation. The reactions of these complexes with MeLi and AlMe3 were studied by 1H, 13C{1H...     »

ISI Document Delivery No.: 071TN Times Cited: 0 Cited Reference Count: 43 Bartlett, Stuart A. Cibin, Giannantonio Dent, Andrew J. Evans, John Hanton, Martin J. Reid, Gillian Tooze, Robert P. Tromp, Moniek Evans, John/A-4800-2013; Reid, Gillian/B-9110-2009 Evans, John/0000-0003-3290-7785; Epsrc [ep/032463/1] We thank the EPSRC (EP/032463/1) for support, and Diamond Light Source Ltd for access to the synchrotron facilities (under experiment SP7232-1). Sasol Technology Pty are thanked for permission to publish. 0 Royal soc chemistry Cambridge     «

ISI Document Delivery No.: 071TN Times Cited: 0 Cited Reference Count: 43 Bartlett, Stuart A. Cibin, Giannantonio Dent, Andrew J. Evans, John Hanton, Martin J. Reid, Gillian Tooze, Robert P. Tromp, Moniek Evans, John/A-4800-2013; Reid, Gillian/B-9110-2009 Evans, John/0000-0003-3290-7785; Epsrc [ep/032463/1] We thank the EPSRC (EP/032463/1) for support, and Diamond Light Source Ltd for access to the synchrotron facilities (under experiment SP7232-1). Sasol Technology Pty are thanked for permiss...     »