Probing the effect of heterocycle-bonding in PNX-type ruthenium pre-catalysts for reactions involving H2.
A series of ruthenium(ii) complexes with three novel PNX-type pincer ligands is reported, in which X denotes a heterocyclic donor group (PNX = Ph2PCH2CH2N(H)CH2-X, X = 2-pyridyl, 2-furanyl, 2-thiophenyl or 2-pyrrolyl). The reaction of [(Ph3P)3RuCl2] with one equivalent of ligand leads to the trans-dichloro complexes [(PNX)RuCl2(PPh3)] (1-4) for all ligands, whereas the complexation of [(Ph3P)3Ru(H)(Cl)(CO)] results in different types of complexes. The variation of the heterocyclic donor group is in line with different binding properties and a labilization of this group. Investigations on the catalytic activity of different types of ruthenium(ii) complexes in hydrogenation and dehydrogenation reactions reveal that more labile bound heterocycle donors result in a decrease of catalytic productivity and activity.
Lehn Institute of Functional Materials (LIFM), Sun Yat-Sen University (SYSU), Xingang Road West, Guangzhou 510275, PR China.
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D002384:Catalysis; D018360:Crystallography, X-Ray; D006571:Heterocyclic Compounds / Q000737:chemistry*; D006859:Hydrogen / Q000737:chemistry*; D006865:Hydrogenation; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000737:chemistry*; D017975:Ruthenium Compounds / Q000737:chemistry*
D006571:Heterocyclic Compounds; D009942:Organometallic Compounds; D017975:Ruthenium Compounds; D006859:Hydrogen