LBNL Catalysis Program Project Description
Synthetic chemistry has reached the level of sophistication at
which it is possible to plan and execute the creation of new structures
following the principles of molecular architecture. This project
has targeted for synthesis polyorganometallics, because they have
great potential as catalysts for known or new organic transformations,
and as building blocks for novel materials. Classical routes toward
their assembly lack specificity and predictability, and their
chemistry is complicated by dissociation into smaller fragments.
The research follows an interdisciplinary approach to the designed
construction of polymetallic arrays, anchored rigidly on novel
p-ligands that enforce hitherto unprecedented
metallic topologies. For this purpose, new synthetic organic methodology
has been developed that allows the stepwise chemo-, regio-, and
loco- (i.e., identity of the metal sequence in heterometallic
systems) specific building-up of strain and/or electronically
activated p-systems and attached cluster-chains.
The physical and chemical properties of the resulting molecules
are unparalleled and include: extreme ligand deformations, highly
strained metal-metal bonds, intramolecular organic fragment migrations,
new organic reactions, intrachain electron transfers, and thermally
reversible photochemical storage processes.
Specific current projects involve:
- The chemistry of fulvalene dimetals (Ru, Re, Ir, Rh), especially
in Si-H and C-H activations, C-C bond formations by oligomerization
of alkenes and alkynes, sulfidation, and hydrogenation.
- The development of new methodology to effect cyclopentadienylations
of organometallic substrates on route to oligocyclopentadienylmetals
as novel clusters with "unnatural" connectivities.
- The kinetics and mechanism of intramolecular electron transfer
in tercyclopentadienyltrimetals.
- The exploration of the scope and mechanism of a novel synthesis
of metal-encapsulating carbon nanotubes.
- Potential catalytic applications of metal crystallites embedded
in multiwalled carbon tubes and onions, especially in shape-,
chemo-, regio-, and stereospecific carbon- carbon bond formations
and related transformations.
