The development of an efficient catalytic process that mimics the enzymatic function of alcohol dehydrogenase is critical for using biomass alcohols for both the production of H2 as a chemical energy carrier and fine chemicals under waste-free conditions. Dehydrogenation of alcohol-water mixtures into their corresponding acids with molecular hydrogen as the sole by-product from the reaction can be catalysed by a ruthenium complex with a chelating bis(olefin) diazadiene ligand. This complex, [K(dme)2][Ru(H)(trop2dad)], stores up to two equivalents of hydrogen intramolecularly, and catalyses the production of H2 from alcohols in the presence of water and a base under homogeneous conditions. The conversion of a MeOH-H2O mixture proceeds selectively to CO2/H2 gas formation under neutral conditions, thereby allowing the use of the entire hydrogen content (12% by weight). Isolation and characterization of the ruthenium complexes from these reactions suggested a mechanistic scenario in which the trop2dad ligand behaves as a chemically 'non-innocent' co-operative ligand.

The oxazoline moiety is a ubiquitous, privileged structural element of chiral ligands.[1] The rigid nature of the fivemembered oxazoline ring, the ease of synthesis and the ready availability of many differently substituted derivatives add to their attractiveness. The most well-known oxazoline ligands are bisoxazolines (BOX) [2] and phosphine-oxazolines (PHOX), [3] but many more heterobidentate oxazoline ligands, such as phosphinites, [4] phosphites, [5] pyridines, [6] phosphoramidates, [7] phenols, [8] alcohols, [9] sulfoxides, [10] sulfonamides, [11] thioethers, [12] and N-heterocyclic carbenes [13] have been successfully applied in asymmetric catalysis. Despite the structural diversity of these systems, only h 1 -binding, singledonor-atom ligands have been combined with the oxazoline fragment. Inspired by the recent success of chiral olefin ligands in asymmetric catalysis, [14] we reasoned that the combination of h 2 -binding olefins with oxazolines would allow new coordination geometries and possibilities. We present herein the ready synthesis of modular and easily tunable olefin-oxazoline ligands (OlefOx) and their successful application in asymmetric catalysis. We began with the preparation of a series of electronically and sterically varied olefin-oxazolines (Scheme 1).In each case, olefin and oxazoline were attached to a benzene ring (internal ring) in a 1,2-fashion. As an illustrative example, the highly modular three-step synthesis of ligand 5 is discussed (Schemes 2 and 3). Starting from commercially available 2-methyl benzaldehyde, the oxazoline ring was Scheme 1. Olefin-oxazoline ligands prepared in this study.Scheme 2. Synthesis of olefin-oxazoline ligand 5.[16] Reagents and conditions: a) (S)-phenylalaninol, CH 2 Cl 2 , room temperature, 16 h; then N-bromosuccinimide (NBS), room temperature, 30 min, 75 %; b) tBuLi, LiNCy 2 (Cy = cyclohexyl), ClPO(OEt) 2 , THF, À78 8C to room temperature, 16 h, 47 %; c) KOtBu, toluene, 3,4-dimethoxybenzaldehyde, room temperature, 15 h, 74 %.

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Copolymers of 2,3,4,5,6‐pentafluorostyrene (PFS) having a combination of high hydrophobicity and high glass transition temperature (Tg) are reported here for the first time. The copolymerization was carried out using N‐phenylmaleimide (NPM) as the comonomer and azobisisobutyronitrile (AIBN) as the initiator under both conventional thermal heating and microwave heating. The initial copolymerization rate was found to be higher under microwave heating than under thermal heating. The copolymerization parameters were determined using the Fineman–Ross method and were found to be r1 (NPM) = 0.28 and r2 (PFS) = 0.86. Increased incorporation of NPM in the copolymers led to an increase in Tg of the copolymers without significantly affecting the hydrophobicity of poly(2,3,4,5,6‐pentafluorostyrene). Thermal stability of the copolymers is also reported. Copyright © 2005 Society of Chemical Industry

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