Synthesis and Characterization of Novel Inorganic-Organic Hybrid Ru(II) Complexes and Their Application in Selective Hydrogenation

Abstract

Novel Ru(II) complex-based hybrid inorganic-organic materials immobilized via a diamine co-ligand site instead of the conventional diphosphine ligand have been prepared. The complexes were prepared by two different methods: sol-gel and surface modification techniques. The structures of the desired materials were deduced by several available physical measurements like elemental analyses, infrared, FAB-MS and 1H-, 13C- and 31P-NMR spectroscopy. Due to a lack of solubility the structures of xerogel 3 and modified 4 were studied by solid state 13C-, 29Si- and 31P-NMR spectroscopy, infrared spectroscopy and EXAFS. These materials were stable enough to serve as hydrogenation catalysts. Selective hydrogenation of functionalized carbonyls in α,β-unsaturated compounds was successfully carried out under mild conditions in a basic medium using these complexes as catalysts.

Supported and Non-Supported Ruthenium(II)/Phosphine/[3-(2-Aminoethyl)aminopropyl]trimethoxysilane Complexes and Their Activities in the Chemoselective Hydrogenation of trans-4-Phenyl-3-butene-2-al

“…Preferential reduction of a C=O function over a coexisting C=C linkage is an important and difficult task. Although there are many examples of highly efficient catalysts for olefin and ketone reduction, imine hydrogenation is still a challenge in terms of both the turnover frequency and the lifespan of the active catalyst [ 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 ]. One of the best transition-metal complexes for ketone hydrogenation that has been discovered is the chiral Ru(II)–diphosphine/1,2-diamine complex, which was developed by Noyori [ 3 ].…”

“…By the introduction of T-functionalized into the diamine ligands coordinated complexes, these complexes can be easily immobilized as atypical interphase to a polysiloxane matrix by sol-gel process [ 9 , 10 , 17 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 ]. In such interphases the stationary phase (comprising active centers, polymer and spacer) and a mobile component (gas, liquid or dissolved reactants) penetrate each other on a molecular scale without forming a homogeneous phase [ 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 ].…”

“…In such interphases the stationary phase (comprising active centers, polymer and spacer) and a mobile component (gas, liquid or dissolved reactants) penetrate each other on a molecular scale without forming a homogeneous phase [ 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 ]. When such interphases are provided with a swellable polymer, they may imitate homogeneous conditions as the active centers become highly mobile, simulating the properties of a solution [ 9 , 10 , 17 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 ].…”

“…Recently we have synthesized a number of ruthenium(II) complexes of the [RuCl 2 (P) 2 (N) 2 ] type using both mondentate or bidentate phodsphine and amine ligands, and these complexes were tested as hydrogenation catalysts for functionalized carbonyl compounds. Our ongoing research interest is in synthesizing supported and non-supported phosphine/diamine Ru(II) complexes, then examining their activity for catalytic hydrogenation in both homogenous and heterogeneous phase [ 9 , 10 , 17 ].…”

Kinetics and Mechanism of Oxidation of L‐Cysteine by Bis‐3‐di‐2‐pyridylketone‐2‐thiophenylhydrazone‐iron(III) Complex in Acidic Medium

“…Transition metals in a higher oxidation state can generally be stabilized by suitable chelation of polydentate ligands to establish the proper complexes. Such of these complexes with ligand systems containing multidentate nitrogen or/ and phosphine-donor atoms have been used successfully to promote the transformation of organic compounds [3][4][5][6][7][8] . As oxidizing reagents metal chelates complexes such as hexacyanoferrate(III), dihydroxydiperdatonickelate(IV), bisenylendiamine-cobalt(II), chloramines-B and biphenyl-diamineruthenium(II) [9][10][11][12] have been used to oxidize cysteine in a medium with an appropriate pH value.…”