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1.
ACS Appl Mater Interfaces ; 14(48): 53936-53946, 2022 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-36417669

RESUMO

The enantioselective discrimination of racemic compounds can be achieved through the design and preparation of a new family of chiral conjugated BINOL-porous polymers (CBPPs) from enantiopure (R)- or (S)-BINOL derivatives and 1,3,5-tris(4-phenylboronic acid)benzene or 1,3,5-tris(4-ethynylphenyl)benzene, 1,3,5-triethynyl-2,4,6-trifluorobenzene, and tetra(4-ethynylphenyl)methane as comonomers following Suzuki-Miyaura and Sonogashira-Hagihara carbon-carbon coupling approaches. The obtained CBPPs show high thermal stability, a good specific surface area, and a robust framework and can be applied successfully in the fluorescence recognition of enantiomers of terpenes (limonene and α-pinene) and 1-phenylethylamine. Fluorescence titration of CBPPs-OH in acetonitrile shows that all Sonogashira hosts exhibit a preference for the (R)-enantiomer over the (S)-enantiomer of 1-phenylethylamine, the selectivity being much higher than that of the corresponding BINOL-based soluble system used as a reference. However, the Suzuki host reveals a preference toward (S)-phenylethylamine. Regarding the sensing of terpenes, only Sonogashira hosts show enantiodifferentiation with an almost total preference for the (S)-enantiomer of limonene and α-pinene. Based on the computational simulations and the experimental data, with 1-phenylethylamine as the analyte, chiral recognition is due to the distinctive binding affinities resulting from N···H-O hydrogen bonds and the π-π interaction between the host and the guest. However, for limonene, the geometry of the adsorption complex is mostly governed by the interaction between the hydroxyl group of the BINOL unit and the C═C bond of the iso-propenyl fragment. The synthetic strategy used to prepare CBPPs opens many possibilities to place chiral centers such as BINOL in porous polymers for different chiral applications such as enantiomer recognition.

2.
Dalton Trans ; 40(37): 9589-600, 2011 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-21853185

RESUMO

Chiral compounds prepared from proton sponge building block 8-((2R,5R)-2,5-dimethylpyrrolidin-1-yl)naphthalen-1-amine were found to be effective chiral ligands for obtaining complexes of rhodium(I) and palladium(II) by reaction with [RhCl(cod)](2), PdCl(2)(cod) or Pd(OAc)(2). The complexes bearing triethoxysilane groups were immobilized on mesoporous MCM-41 in order to obtain new heterogeneous catalysts. Both materials are active in the hydrogenation of alkenes and could be recycled without loss of activity or enantioselectivity.

3.
Chem Commun (Camb) ; 46(17): 3001-3, 2010 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-20386848

RESUMO

Biscarbene ligands with two imidazolin-2-ylidene moieties at a chiral dioxolane backbone were used as ligands for gold, rhodium and palladium complexes. All new complexes showed varying degrees of enantioselectivity toward hydrogenation of prochiral alkenes with ees up to 95%.

4.
Dalton Trans ; (1): 168-76, 2009 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-19081986

RESUMO

The oxidative coupling of 2-[Co(2)(CO)(4)(micro-X){micro(2)-eta(2)-(SiMe(3)C(2))}]-5-(C[triple bond]CH)C(4)H(2)S (X = dppa (1), dppm (2)) and 3-[Co(2)(CO)(4)(micro-dmpm){micro(2)-eta(2)-(SiMe(3)C(2))}]-4-(C[triple bond]CH)C(4)H(2)S (3) using standard Eglinton-Glaser conditions yielded 2,2'-[Co(2)(CO)(4)(micro-X){micro(2)-eta(2)-(SiMe(3)C(2))}C(4)H(2)S](2)-5,5'-(C[triple bond]C)(2) (X = dppa (4), dppm (5)) and 3,3'-[Co(2)(CO)(4)(micro-dmpm){micro(2)-eta(2)-(SiMe(3)C(2))}C(4)H(2)S](2)-4,4'-(C[triple bond]C)(2) (6), respectively (dppa = (Ph(2)P)(2)NH; dmpm = (Me(2)P)(2)CH(2); dppm = (Ph(2)P)(2)CH(2)). The reaction of 5 with [Os(3)(CO)(11)(CH(3)CN)] afforded 2,2'-[Co(2)(CO)(4)(micro-dppm){micro(2)-eta(2)-(SiMe(3)C(2))}C(4)H(2)S](2)-5,5'-[Os(3)(CO)(11)(micro(3)-eta(4)-(C[triple bond]C)(2)] (7), where the triosmium cluster is open and coordinated as a linear chain to both triple bonds. The electrochemical study of 7 shows that the "Os(3)" unit significantly enhances the electronic communication between the "Co(2)" redox centres as compared with 5. Complex 6 was characterized by single-crystal X-ray diffraction analyses.

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