The face-to-face stacking interaction between phenyl and perfluorophenyl groups is emerging as a common noncovalent interaction. To explore the generality of this supramolecular synthon, the solid-state packing structure and reactivity of several monoolefins and diolefins substituted with phenyl and perfluorophenyl groups was investigated. Of the seven crystalline or cocrystalline materials investigated, six were found to undergo a photochemically induced [2+2] reaction in the solid state. By determining the stereochemistry of the photoproduct and/or X-ray structural analysis of the olefinic precursors, the stacked interaction between phenyl and perfluorophenyl groups in the photoactive crystals were revealed.

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Crystal Size: 0.10 x 0.11 x 0.23 mm pcj. = 2.57 g cm Crystal System: Orthorhombic Space group: Cm a = 17.669(5) A b = 9.081(2) A c = 6.804(2) A V = 1091.7(5) A 3 Z=4 Lattice parameters: 29 reflections 9.50 <0 < 10.50 p. = 134.5 cm-1 Tansmission co Variable-temperature P! diffractometer 0-20 scan MoKa, A = 0.7107A Graphite mono 20 range: 20-600-24 < h < 21,-T = 294K Number of reflections measured: 6993 Number of idei Number with FO > 0: 868 Number with F. Standard reflections: 3 every 97 data Variation: within GOFmerge: 1.06 for 877 multiples Rmerge: 0.018 fo

The structure was solved with SHELXS-86 using direct methods.The hydrogen atoms were originally placed at calculated positions. Eventually the coordinates of all but two (H38a and H38b, see below) were refined, with Uio's fixed at 1.2 times the Ue of the attached atom. Refinement was full-matrix least-squares using SHELXL-93.Definitions

S1 S2 EXPERIMENTAL SECTION Synthesis of N-formyl-4-bromo-2,6-diisopropylaniline. Acetic anhydride (40 mL, 422.7 mmol) was cooled to 0 °C and formic acid (20 mL, 530.1 mmol) was added via syringe over 10 minutes. The colorless solution was allowed to warm to room temperature, then heated at 50 °C for 2 hours. The solution was then allowed to cool to room temperature and then cooled to 0 °C. 4-bromo-2,6-diisopropylaniline was added via syringe, and the mixture was then allowed to warm to room temperature. The mixture was allowed to stir for 30 minutes, then cooled to 0 °C, followed by the addition of 0 °C H2O (ca. 300 mL), resulting in the formation of a light pink suspension. The mixture was filtered, and the precipitate was washed with H2O (ca. 1 L). The white precipitate was dried in vacuo overnight to give N-formyl-4-bromo-2,6diisopropylaniline (5.05 g, 76%) as a white solid. Mixture of isomers 1 H NMR (CDCl3): 1.16 [d, 3 JH-H = 7 Hz, 12H,

Dinickel bisphenoxyiminato complexes based on highly substituted p- and m-terphenyl backbones were synthesized, and the corresponding atropisomers were isolated. In the presence of a phosphine scavenger, Ni(COD)2, the phosphine-ligated syn-dinickel complexes copolymerized α-olefins and ethylene in the presence of amines to afford 0.2–1.3% α-olefin incorporation and copolymerized amino olefins and ethylene with a similar range of incorporation (0.1–0.8%). The present rigid catalysts provide a bimetallic strategy for insertion polymerization of polar monomers without masking of the heteroatom group. The effects of the catalyst structure on the reactivity were studied by comparisons of the syn and anti atropisomers and the p- and m-terphenyl systems.

Ruthenium alkylidenes 6 and 7 bearing cationically functionalized phosphine ligands are soluble and stable in protic solvents and initiate olefin metathesis reactions in methanol, water, and aqueous emulsions. NMR spectroscopy data and X-ray diffraction analyses of alkylidene 6 suggested that these new alkylidenes were structurally similar to previously reported complexes of the type (PR 3 ) 2 Cl 2 RudCHR, in which the alkylidene substituents lie in the Cl-Ru-Cl plane. The anionic chloride ligands of complexes 6 and 7 were found to undergo facile ligand exchange reactions with other anions in protic solution. Both alkylidenes initiate the ring-opening metathesis polymerization (ROMP) of strained, cyclic olefins in water. However, the propagating species in these reactions decompose prior to complete consumption of monomer. These complexes initiate the quantitative, living polymerization of functionalized monomers in water in the presence of a Brønsted acid. Both chain termination and chain transfer reactions were experimentally demonstrated to be absent on the time scale of these acid-activated polymerizations. Alkylidenes 6 and 7 react readily with acyclic olefins: alkylidene 6 reacted with trans-2-butene to yield a new ethylidene complex in either methanol or water, and the treatment of 6 with tri(ethylene glycol) methyl vinyl ether in water yielded water-soluble Fischer-carbene complex 16.

A series of second-generation ruthenium olefin metathesis catalysts was investigated using a combination of reaction kinetics, X-ray crystallography, NMR spectroscopy, and DFT calculations in order to determine the relationship between the structure of the chelating oalkoxybenzylidene and the observed initiation rate. Included in this series were previously reported catalysts containing a variety of benzylidene modifications as well as four new catalysts containing cyclopropoxy, neopentyloxy, 1-adamantyloxy, and 2-adamantyloxy groups. The initiation rates of this series of catalysts were determined using a UV/vis assay. All four new catalysts were observed to be faster-initiating than the corresponding isopropoxy control, and the 2-adamantyloxy catalyst was found to be among the fastest-initiating Hoveyda-type catalysts reported to date. Analysis of the X-ray crystal structures and computed energy-minimized structures of these catalysts revealed no correlation between the Ru−O bond length and Ru−O bond strength. On the other hand, the initiation rate was found to correlate strongly with the computed Ru−O bond strength. This latter finding enables both the rationalization and prediction of catalyst initiation through the calculation of a single thermodynamic parameter in which no assumptions about the mechanism of the initiation step are made.