A variety of popular ionic liquids have been synthesized and characterized, including by optimized (14)N NMR spectroscopy of the neat and dissolved ionic liquids. Ionic liquids incorporating Si(OEt)(3) groups have been immobilized on silica in a well-defined manner with the imidazolium moiety remaining intact. This has been proved by optimized one- and two-dimensional (1)H and (13)C HRMAS NMR spectroscopy of the materials suspended in suitable solvents.

The title technique, high-resolution magic angle spinning NMR of suspensions, constitutes a powerful new tool for investigating the structures and mobilities of immobilized species and, thus, for optimizing heterobimetallic catalyst systems, such as the Sonogashira coupling of terminal alkynes and aryl halides.

A new chelate phosphine linker and its Pd and Cu complexes have been synthesized and immobilized. The solvent impact on these immobilized species, their mobility, and coordination preferences have been studied in situ by HRMAS (High-Resolution Magic Angle Spinning) NMR. The catalyst recycling characteristics match the HRMAS results.

A new bisphosphinoamine linker with ethoxysilyl group has been synthesized and applied for anchoring nickel catalysts to alumina and silica. Side reactions occurred, and the reactions of various bisphosphinoamine ligands with silica were studied by 31 P CP/MAS and suspension HR-MAS NMR. Besides the desired immobilization, two main side reactions have been found. The phosphine moieties of the linkers can be quaternized by ethyl groups from the ethoxysilyl functions. Furthermore, the bisphosphinoamine group can rearrange to the corresponding phosphinimine unit that is subsequently hydrolyzed, resulting in the amine and tetraphenyldiphosphine oxide. The latter is bound firmly to the silica surface.

Vertical and adiabatic electron attachment to carbon dioxide clusters (CO2)N (N=2–5) is studied at high ab initio levels of theory. As a first step the geometries of neutral and anionic CO2 clusters are reexamined. The potential energy surfaces of both neutral and anionic CO2 clusters show many minima, and several isomers have been reported so far. Here we present new lowest-energy isomers for the tetramer and pentamer anion clusters, as well as high-level results for relative and CO2 evaporation energies. Electron correlation is crucial for the computed properties, and since we had to make certain compromises about the theoretical level in order to include larger clusters, a thorough investigation of different ab initio methods is performed for the dimer. The vertical affinities of the investigated (CO2)N clusters are found to be clearly negative; i.e., vertical attachment into valence orbitals leads to temporary anion states. The energies of these resonances as well as the associated autodetachment lifetimes are computed using complex absorbing potentials at the frozen-orbital and correlated second-order Green’s function levels. Whereas the cluster environment has a surprisingly weak influence on the negative vertical affinities, solvation has a strong effect on the adiabatic electron affinities. The computed trends suggest that the tetramer is at the brink of stability and that the pentamer cluster is the smallest species possessing an appreciable positive electron affinity. Our findings have profound implications for the interpretation of the low-energy electron attachment experiments and provide a basis for the discussion and modeling the attachment process.