Synthesis of ruthenium carbonyl complexes with phosphine or substituted Cp ligands, and their activity in the catalytic deoxygenation of 1,2-propanediol.

A ruthenium hydride with a bulky tetra-substituted Cp ligand, (Cp(i)(Pr(4)))Ru(CO)(2)H (Cp(i)(Pr(4)) = C(5)(i-C(3)H(7))(4)H) was prepared from the reaction of Ru(3)(CO)(12) with 1,2,3,4-tetraisopropylcyclopentadiene. The molecular structure of (Cp(i)(Pr(4)))Ru(CO)(2)H was determined by X-ray crystallography. The ruthenium hydride complex (C(5)Bz(5))Ru(CO)(2)H (Bz = CH(2)Ph) was similarly prepared. The Ru-Ru bonded dimer, [(1,2,3-trimethylindenyl)Ru(CO)(2)](2), was produced from the reaction of 1,2,3-trimethylindene with Ru(3)(CO)(12), and protonation of this dimer with HOTf gives {[(1,2,3-trimethylindenyl)Ru(CO)(2)](2)-(mu-H)}(+)OTf (-). A series of ruthenium hydride complexes CpRu(CO)(L)H [L = P(OPh)(3), PCy(3), PMe(3), P(p-C(6)H(4)F)(3)] were prepared by reaction of Cp(CO)(2)RuH with added L. Protonation of (Cp(i)(Pr(4)))Ru(CO)(2)H, Cp*Ru(CO)(2)H, or CpRu(CO)[P-(OPh)(3)]H by HOTf at -80 degrees C led to equilibria with the cationic dihydrogen complexes, but H(2) was released at higher temperatures. Protonation of CpRu[P(OPh)(3)](2)H with HOTf gave an observable dihydrogen complex, {CpRu[P-(OPh)(3)](2)(eta(2)-H(2))}(+)OTf (-) that was converted at -20 degrees C to the dihydride complex {CpRu[P(OPh)(3)](2)(H)(2)}(+)OTf (-). These Ru complexes serve as catalyst precursors for the catalytic deoxygenation of 1,2-propanediol to give n-propanol. The catalytic reactions were carried out in sulfolane solvent with added HOTf under H(2) (750 psi) at 110 degrees C.

Estimation of atmospheric lifetimes of hydrofluorocarbons, hydrofluoroethers, and olefins by chlorine photolysis using gas-phase NMR spectroscopy.

An empirical correlation has been derived between accepted atmospheric lifetimes of a set of hydrofluorocarbons and hydrofluoroethers and relative rates of reaction with photolyzed chlorine in excess at ambient temperature. These kinetic systems were studied by nuclear magnetic resonance (NMR) spectroscopy in the gas phase, marking the first application of NMR spectroscopy to this field. The square of the Pearson coefficient R for the linear correlation between observed reaction rates and accepted atmospheric lifetimes was 0.87 for compounds of lifetime less than 20 years. The method was extended to the study of ethene and propene; the rate of reaction of propene was found to be 1.25 times that of ethene at 23 degrees C. The chief advantage of this method is its simplicity and reliance only on common tools and techniques of an industrial chemical laboratory.

Solvent-free ketone hydrogenations catalyzed by molybdenum complexes.

Et2C=O is hydrogenated under solvent-free conditions using a catalyst prepared by hydride abstraction from HMo(CO)2[eta5:eta1-C5H4(CH2)(2)PCy2]; the catalyst functions at low catalyst loadings (< 0.4 mol%).

Metal-Catalyzed Selective Deoxygenation of Diols to Alcohols.

The internal OH group of 1,2-propanediol is selectively removed in the deoxygenation catalyzed by [{Cp*Ru(CO)2 }2 (µ-H)]+ OTf- (1, Cp*=C3 Me5 , OTf=trifluoromethanesulfonate; see scheme). This reaction provides a model for deoxygenation of polyols derived from carbohydrates, for use in alternative, biomass-based feedstock applications. An ionic mechanism is proposed that involves the dihydrogen complex [Cp*Ru(CO)2 (η2 -H2 )]+ .

Quantum interference of large organic molecules.

The wave nature of matter is a key ingredient of quantum physics and yet it defies our classical intuition. First proposed by Louis de Broglie a century ago, it has since been confirmed with a variety of particles from electrons up to molecules. Here we demonstrate new high-contrast quantum experiments with large and massive tailor-made organic molecules in a near-field interferometer. Our experiments prove the quantum wave nature and delocalization of compounds composed of up to 430 atoms, with a maximal size of up to 60 Å, masses up to m=6,910 AMU and de Broglie wavelengths down to λ(dB)=h/mv≃1 pm. We show that even complex systems, with more than 1,000 internal degrees of freedom, can be prepared in quantum states that are sufficiently well isolated from their environment to avoid decoherence and to show almost perfect coherence.