The crystal structure of [4,4,4-trifluoro-3,3-dihydroxy-1-phenyl-1-butanonato(2–)-O,O',0'']tris(p-tolyl)antimony(V)–1,2-dichloroethane (2/1)

Ebina, Fujio; Ouchi, Akihiko; Yoshino, Yukichi; Sato, Shinya; Saitō, Yasushi

doi:10.1107/s0567740878006019

Cited by 10 publications

(3 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The Sb-O(1) distance is slightly longer than the Sb-O(acetylacetonate) bond of 2.117 (10)/~, (Kroom, Hulscher & Peerdeman, 1972), whereas the Sb-O(2) bond is unusually long [its value is similar to those observed in the two hydrated compounds, 2.534 (8) and 2.568 (2) A (Ebina et al, 1977(Ebina et al, , 1978]. The O(1)-C(2) distance is close to the values for coordinated C... O groups of trifluoroacetylacetonate and acetylacetonate (Kroom et al, 1972;Cotton & Winquist, 1969;Lingafelter & Braun, 1966) and, on the other hand, the O(2)-C(4) distance of 1.235 (6) ,/~ is typical for free C=O groups (International Tables for X-ray Crystallography, 1968).…”

Section: Ci(s)-c(s)-ci'(s) 1189 (16) Ci(s)-c(s)-ci"(s) 947 (13) Ci'supporting

confidence: 50%

“…The crystal structures of the two reaction products have already been determined (Ebina, Ouchi, Yoshino, Sato & Saito, 1977;Ebina, Ouchi, Yoshino, Sato & Saito, 1978). In the two products, the coordinated fl-diketonate is hydrated at the C...C group attached to the CF a group, to form a novel terdentate ligand: the fl, pdihydroxyketone dianion.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

The crystal structure of μ-oxo-bis[tris(p-chlorophenyl)(1,1,1-trifluoro-2,4-pentanedionato-O,O')-antimony(V)]–chloroform (1/2)

Ebina¹,

Ouchi²,

Yoshino³

et al. 1978

Acta Crystallogr Sect B

Self Cite

View full text Add to dashboard Cite

show abstract

Section: Ci(s)-c(s)-ci'(s) 1189 (16) Ci(s)-c(s)-ci"(s) 947 (13) Ci'supporting

confidence: 50%

Section: Introductionmentioning

confidence: 99%

The crystal structure of μ-oxo-bis[tris(p-chlorophenyl)(1,1,1-trifluoro-2,4-pentanedionato-O,O')-antimony(V)]–chloroform (1/2)

Ebina¹,

Ouchi²,

Yoshino³

et al. 1978

Acta Crystallogr Sect B

Self Cite

View full text Add to dashboard Cite

show abstract

“…However, coordinated aldehyde 11 can be in equilibrium with a metalloacetal-containing species 18. [49] This would force the salen ligand into the cis-b configuration [50] and account for the observed asymmetric induction. Although it has not proven possible to detect complex 18, the corresponding titanium-based complex has previously been detected.…”

Section: Cyclic Voltammetrymentioning

confidence: 99%

Mechanism‐Guided Development of VO(salen)X Complexes as Catalysts for the Asymmetric Synthesis of Cyanohydrin Trimethylsilyl Ethers

Belokoń

Clegg

Harrington

et al. 2009

Chemistry A European J

View full text Add to dashboard Cite

Catalyze this! Detailed study of the mechanism of asymmetric cyanohydrin synthesis catalyzed by VO(salen)X complexes (see figure) led to the development of VO(salen)NCS, as the most active vanadium-based catalyst yet developed for this reaction.The mechanism by which oxovanadium(V)(salen) complexes(1) VO(salen)X catalyze the asymmetric addition of trimethylsilyl cyanide to benzaldehyde has been studied. The reaction kinetics indicated that the structure of the counterion (X) had a significant influence on the rate, but not on the enantioselectivity of the reaction. The less coordinating the counterion, the lower the catalytic activity; a trend that was confirmed by a Hammett analysis. Variable temperature kinetics allowed the enthalpies and entropies of activation to be determined for some catalysts, and showed that, for others, the overall reaction order changes from second order to zero order as the temperature is reduced. The order with respect to the catalyst was determined for nine of the VO(salen)X complexes and showed that the less active catalysts were active predominantly as mononuclear species whilst the more active catalysts were active predominantly as dinuclear species. Mass spectrometry confirmed the formation of dinuclear species in situ from all of the VO(salen)X complexes and indicated that the dinuclear complexes contained one vanadium(V) and one vanadium(IV) ion. The latter conclusion was supported by cyclic voltammetry of the complexes, by fluorescence measurements and by the fact that catalyst deactivation occurs when reactions are carried out under an inert atmosphere. Based on this evidence, it has been deduced that the catalysis involves two catalytic cycles: one for catalysis by mononuclear VO(salen)X species and the other for catalysis by dinuclear species. The catalytic cycle involving dinuclear species involves activation of both the cyanide and aldehyde, whereas the catalytic cycle involving mononuclear species activates only the aldehyde, thus explaining the higher catalytic activity observed for catalysts which are predominantly active as dinuclear complexes. Based on these mechanistic results, two new VO(salen)X complexes (X=F and NCS) were predicted to form highly active catalysts for asymmetric cyanohydrin synthesis. VO(salen)NCS was indeed found to be the most active catalyst of this type and catalyzed the asymmetric addition of trimethylsilyl cyanide to thirteen aldehydes. In each case, high yields and enantioselectivities were obtained after a reaction time of two hours at room temperature using just 0.1 mol % of the catalyst.

show abstract

Organoantimony Compounds with Pentavalent Antimony

Wieber

1986

Sb Organoantimony Compounds Part 4

View full text Add to dashboard Cite

The crystal structure of [4,4,4-trifluoro-3,3-dihydroxy-1-phenyl-1-butanonato(2–)-O,O',0'']tris(p-tolyl)antimony(V)–1,2-dichloroethane (2/1)

Cited by 10 publications

References 1 publication

The crystal structure of μ-oxo-bis[tris(p-chlorophenyl)(1,1,1-trifluoro-2,4-pentanedionato-O,O')-antimony(V)]–chloroform (1/2)

The crystal structure of μ-oxo-bis[tris(p-chlorophenyl)(1,1,1-trifluoro-2,4-pentanedionato-O,O')-antimony(V)]–chloroform (1/2)

Mechanism‐Guided Development of VO(salen)X Complexes as Catalysts for the Asymmetric Synthesis of Cyanohydrin Trimethylsilyl Ethers

Organoantimony Compounds with Pentavalent Antimony

Contact Info

Product

Resources

About