Paul J. Fagan

The Chemical Nature of Buckminsterfullerene (C60) and the Characterization of a Platinum Derivative

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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 λdB=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.

Production of Perfluoroalkylated Nanospheres from Buckminsterfullerene

Perfluoroalkylated nanospheres have been prepared by reaction of fullerenes with a variety of fluoroalkyl radicals. The latter are generated by thermal or photochemical decomposition of fluoroalkyl iodides or fluorodiacyl peroxides. Up to 16 radicals add to C60 to afford easily isolable fluoroalkylated derivatives. The monosubstituted radical adducts were detected by electron spin resonance in the early stages of the fluoroalkylation reactions. These spheroidal molecules are thermally quite stable, soluble in fluoroorganic solvents, chemically resistant to corrosive aqueous solutions, and more volatile than the parent fullerenes. Films of the sublimed material display properties typical for a perfluoroalkylated material.

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 )]+ .

Molecular Structure of an Unusual Organoactinide Hydride Complex Determined Solely by Neutron Diffraction

The structure of an unusual organometallic complex, {Th[(CH3)5C5]2 H(�-H)}2 � C6H5CH3, has been determined from neutron diffraction data, using only the direct-methods program MULTAN. Besides providing accurate metrical information on the first organometallic actinide hydride complex, these results have general and far-reaching implications concerning the complexity and size of crystal structures that can be elucidated solely on the basis of neutron diffraction data.

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.

Slow beams of massive molecules

Abstract.Slow beams of neutral molecules are of great interest for a wide range of applications, from cold chemistry through precision measurements to tests of the foundations of quantum mechanics. We report on the quantitative observation of thermal beams of perfluorinated macromolecules with masses up to 6000 amu, reaching velocities down to 11 m/s. Such slow, heavy and neutral molecular beams are of importance for a new class of experiments in matter-wave interferometry and we also discuss the requirements for further manipulation and cooling schemes with molecules in this unprecedented mass range.

Some well characterized chemical reactivities of buckminsterfullerene (C60)

Abstract The metalation, halogenation and free radical addition chemistry of C 60 is described. Vibrational spectroscopy is a useful tool in assigning the structures of the products. Several underlying principles emerge for C 60 chemistry, some of which are supported by molecular orbital calculations.

Coexistence of fcc and hcp phases of C60. Microstructural characterization of C60 and metal complexes of C60

Abstract Direct high resolution transmission electron microscopy (HRTEM) imaging of sublimed C 60 provides good evidence for the coexistence of relatively defect-free fcc and hcp phases in sublimed C 60 . In addition, some previously unobserved defects have been found in C 60 grown from solution. Preliminary results on imaging crystalline metal derivatives of C 60 by TEM are also presented.

Radiative lifetimes of confined excitations in sigma-conjugated silane oligomers

Abstract Emission studies of polysilanes of well-defined length are used to deduce the chain length necessary to support delocalized excitations. The chemical conditions necessary for interruption of extended sigma-conjugation are also described.