Carbon dioxide fixation: bifunctional complexes containing acidic and basic sites working as reversible carriers

Journal Article · Wed Sep 22 00:00:00 EDT 1982 · J. Am. Chem. Soc.; (United States)

DOI:https://doi.org/10.1021/ja00383a015· OSTI ID:6235329

Gambarotta, S ^[1]

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1. Universita' di Pisa, Italy

Carbon dioxide fixation in its intact form is achieved from ''bifunctional'' complexes containing in their structure a nucleophilic cobalt(I) and an alkali cation: Co(R-salen)M (R-salen = substituted salen ligand; salen = N,N'-ethylenebis(salicylideneaminato); M = Li, Na, K, Cs). The fixation of CO/sub 2/ by such systems displays different degrees of reversibility depending on the reaction solvent and the nature of the alkali cation. The X-ray analysis carried out on (Co(n-Pr-salen)K-(CO)/sub 2/(THF)) shows carbon dioxide anchored to the cobalt through a Co-C sigma bond, while the oxygens interact with the alkali cation, in a polymeric structure. IR spectra are diagnostic for the presence of CO/sub 2/ bonded as a bent molecule in a reduced form displaying three strong bands in the following ranges: 1700-1650, 1300-1250, and 1250-1200 cm/sup -1/. The binding of CO/sub 2/ is partially prevented in the presence of a crown ether, which can complex the alkali cation. The reaction of (Co(salen)Na(CO/sub 2/)) and (Co(salen)Na(THF)) with dicyclohexano-18 crown-6(DCHC) gave a complex, (Co(salen)Na)/sub 2/(DCHC), whose structure shows the presence of the intact bifunctional unit where, however, all the coordination sites around the alkali cation are filled by the oxygens from salen and DCHC and are not further available for binding the oxygen atoms of the CO/sub 2/ molecule. Crystallographic details and the final R factor for specific observed reflections are given for (Co(n-Pr-salen)K(CO/sub 2/)(THF))/sub n/, (CO(n-Pr-salen)K(CO/sub 2/)(THF))/sub n/, (Co(salen)Na)/sub 2/(DCHC).

• OSTI ID: 6235329
• Journal Information: J. Am. Chem. Soc.; (United States), Vol. 104:19
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
CARBON DIOXIDE
CHEMICAL ACTIVATION
COBALT COMPLEXES
STRUCTURAL CHEMICAL ANALYSIS
BOND ANGLE
BOND LENGTHS
CARRIERS
ETHYLENE
INFRARED SPECTRA
ORGANIC NITROGEN COMPOUNDS
TETRAHYDROFURAN
ALKENES
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
COMPLEXES
DIMENSIONS
FURANS
HETEROCYCLIC COMPOUNDS
HYDROCARBONS
LENGTH
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
SPECTRA
TRANSITION ELEMENT COMPLEXES
400201* - Chemical & Physicochemical Properties