David L. Thorn

Synthesis and Single-Crystal X-ray Structure of a Highly Symmetrical C60 Derivative, C60Br24

C60 and liquid bromine react to form C60Br24, a crystalline compound isolated as a bromine solvate, C60Br24(Br2)x, The x-ray crystal structure defines a new pattern of addition to the carbon skeleton that imparts a rare high symmetry. The parent C60 framework is recognizable in C60Br24, but sp3 carbons at sites of bromination distort the surface, affecting conformations of all of the hexagonal and pentagonal rings. Twenty-four bromine atoms envelop the carbon core, shielding the 18 remaining double bonds from addition. At 150� to 200�C there is effectively quantitative reversion of C60Br24 to C60 and Br2.

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.

Transition metal-organoindium chemistry. Reaction of trialkylindium compounds with (cyclopentadienyl)(tricarbonyl)metal radicals

Photolysis of [(CpMo(CO)3]2 with InR3 (R = ethyl, t-butyl, neopentyl) or ZnR2 (R = ethyl) efficiently forms CpMo(CO)3InR2 or [(CpMo(CO)3]2Zn as major products. The reaction is believed to proceed by bimolecular radical substitution and demonstrates substantial strenght for the MoIn bond. As a consequence of this bond strenght, [CpMo(CO)3]2 reacts photochemically and reversibly with indium metal to form [CpMo(CO)3]3In.

Electrophilic Stannylation of Arenes: A New SEAr Reaction

Electrophilic “trifluoroacetatotin(IV)” has been prepared by reaction of tin oxide with trifluoroperacetic acid/trifluoroacetic anhydride, and by reaction of tetraphenyltin with excess trifluoroacetic acid. The electrophilic tin(IV) material prepared by either route reacts reversibly with arenes to make aryl-tin compounds and trifluoroacetic acid. The compounds (C6H5)2Sn4O2(CF3COO)10 and (xylyl)2Sn4O2(CF3COO)10 have been obtained from the reactions with benzene and p-xylene, respectively, and their molecular structures determined by X-ray crystallography. Tin now joins Pb, Tl, and Hg in the list of main group metals whose trifluoroacetato complexes can metalate arenes by C−H activation.

Unsymmetrically substituted dimethylplatinum(II) complexes

cis-(Dimethyl)(tri-p-tolylphosphine)(ligand)platinum(II) complexes (ligand  substituted pyridine or amine) have been prepared from PtMe2(1,5-COD) (COD  cyclooctadiene), Ptol3 (tol  tolyl) and the N-donor ligand. For ligand  4-(5-phenyl-2-oxazolyl)pyridine the crystal and molecular structure has been determined: space group R3−, a  b  34.295(5), c  14.198(2) A (− 100°C), γ 120°, V 14459 A3, Z  18. For 379 variables and 4977 reflections with I > 2σ(I) R  0.034, Rw  0.042. PtC bond lengths are 2.082(7) (rans to P) and 2.059(8) A (trans to N). Amine ligands are displaced by ethylene to form an unstable ethylene adduct.

The Crystal Structures of Some New Forms of Aluminum Fluoride as Determined from their Synchrotron Powder Diffraction Patterns

@[Equation] Ok, but surely the phase diagram and the structural details were worked out years ago? As it turns out, until the recent effort to make Freon® substitutes, most of the purported AlF3 phases were known only from their x-ray powder diffraction signatures, very little had been done in the way of actually determining the structures of these materials or even to demonstrate that they actually were pure and unique phases. As the Freon® substitutes program geared up, all of the phases came under closer scrutiny. In addition, new methods of synthesis were yielding previously unknown phases of AIF3 but only in microcrystalline, “powder” form. It was then clear that detailed characterizations of these materials would require ab initio structure determinations from their powder diffraction patterns, the best of which could only be obtained from synchrotron sources. This chapter discusses some of our experiences with this technique and outlines the structural results which we have obtained on a number of aluminum fluoride compounds.