Synthesis of new rhodium complexes with a hemilabile nitrogen-containing bis(phosphinite) or bis(phosphine) ligand. Application to hydroformylation of styrene
摘要:
Two new cationic rhodium(I) complexes with a hemilabile nitrogen-containing bis(phosphinite) or bis(phosphine) ligand have been prepared. P-31-NMR studies provide evidence that the Ligands are coordinated to the metal in P,P-bidentate mode, whereas for the bis(phoshine)-based ligand, a P,N,P-tridentate mode is also possible to be found at low temperatures. The complexes were applied to the hydroformylation of styrene and displayed a high chemoselectivity for aldehydes with a very good branched/linear ratio. (C) 2001 Elsevier Science B.V. All rights reserved.
Synthesis of new rhodium complexes with a hemilabile nitrogen-containing bis(phosphinite) or bis(phosphine) ligand. Application to hydroformylation of styrene
摘要:
Two new cationic rhodium(I) complexes with a hemilabile nitrogen-containing bis(phosphinite) or bis(phosphine) ligand have been prepared. P-31-NMR studies provide evidence that the Ligands are coordinated to the metal in P,P-bidentate mode, whereas for the bis(phoshine)-based ligand, a P,N,P-tridentate mode is also possible to be found at low temperatures. The complexes were applied to the hydroformylation of styrene and displayed a high chemoselectivity for aldehydes with a very good branched/linear ratio. (C) 2001 Elsevier Science B.V. All rights reserved.
Platinum complexes of P,N- and P,N,P-ligands and their application in the hydroformylation of styrene
作者:Péter Pongrácz、Ioannis D. Kostas、László Kollár
DOI:10.1016/j.jorganchem.2012.10.018
日期:2013.1
Neutral complexes of the formula PtCl2(L) (where L - ortho-diphenylphosphino-N-(2-hydroxyethyl)-N-methylaniline (1), ortho-diphenylphosphino-N-2-(diphenylphoshinoxy)-ethyl)-N-methylaniline (2) and N,N-bis(2-(diphenylphoshinoxy) ethyl) aniline (3)) were prepared. Various binding modes, such as P, Nand P, P-bidentate and monodentate coordinations were observed with these hemilabile ligands in the parent complexes and in the triphenylphosphine-added systems. P-31 NMR studies on the 'in situ' systems revealed the hemilabile character of the ligands.The platinum complexes proved to be precursors to catalysts of low activity for the hydroformylation of styrene in platinum-ligand (1, 2 or 3)-tin(II) chloride system. High chemoselectivities (up to 82%) were obtained, while the two aldehyde regioisomers were formed in almost equimolar ratio with the slight preference of the branched aldehyde, 2-phenylpropanal. Remarkable increase in regioselectivity was observed in the presence of para-toluenesulfonic acid additive using platinum-ligand (1) systems. (C) 2012 Elsevier B. V. All rights reserved.