Control of donor-acceptor interactions in organoalkaline-earth-transition-metal complexes. Crystallographic characterization of (Me{sub 5}C{sub 5}){sub 2}HfCl({mu}-Cl)Ca(Me{sub 5}C{sub 5}){sub 2}
- Vanderbilt Univ., Nashville, TN (United States)
The problem of ligand exchange or loss in the formation of organometallic alkaline-earth-transition-metal complexes can be minimized by ensuring that any exchange would be degenerate or would require an unfavorable transfer of ligands. This approach is illustrated in the formation of chloride-bridged calcium-group 4 dimers and in an isocarbonyl-linked calcium-chromium dimer. Bis(pentamethylcyclopentadienyl)calcium Cp*{sub 2}Ca, reacts with Cp*{sub 2}ZrCl{sub 2}, Cp*{sub 2}HfCl{sub 2}, and Cp*{sub 2}ThCl{sub 2} in toluene to yield 1:1 adducts. Orange-yellow crystals of Cp*{sub 2}HfCl({mu}-Cl)CaCp* grown from toluene are triclinic, space group P{bar 1}, with a = 11.146 (4) {angstrom}, b = 16.942 (6) {angstrom}, c = 11.109 (3) {angstrom}, {alpha} = 103.34 (3){degrees}, {beta} = 94.89 (3){degrees}, {gamma} = 102.50 (3){degrees}, and D(calcd) = 1.398 g cm{sup -3} for Z = 2. The structure consists of two bent metallocene units with a single {mu}-Cl and a terminal Cl on hafnium: Ca-{mu}-Cl = 2.864 (3) {angstrom}, Hf-{mu}-Cl = 2.463 (3) {angstrom}, Hf-Cl(t) = 2.383 (3) {angstrom}, and Ca-Cl-Hf = 161.3 (1){degrees}. Cp*{sub 2}Ca reacts with Cp*{sub 2}Zr(CO){sub 2} and mesitylene chromium tricarbonyl in toluene in yield 1:1 adducts. In the solid state, the calcium-chromium adduct exists as a tetranuclear species, constructed around a 12-membered ring consisting of two Ca and Cr atoms and four carbonyl groups. 39 refs., 2 figs., 4 figs.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 567348
- Journal Information:
- Organometallics, Journal Name: Organometallics Journal Issue: 7 Vol. 11; ISSN 0276-7333; ISSN ORGND7
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
40 CHEMISTRY
ADDUCTS
ALKALINE EARTH METAL COMPLEXES
ALKYNES
ALLOYS
BARIUM
CALCIUM
CATALYSTS
CHEMICAL PROPERTIES
CHEMICAL REACTION YIELD
CHEMICAL REACTIONS
CHROMIUM
CRYSTAL STRUCTURE
DIELECTRIC MATERIALS
DIMERS
HAFNIUM
LIGANDS
MESITYLENE
MOLECULAR STRUCTURE
ORGANIC SEMICONDUCTORS
ORGANOMETALLIC COMPOUNDS
STRONTIUM
STRUCTURAL CHEMICAL ANALYSIS
SYNTHESIS
TOLUENE
TRANSITION ELEMENTS