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ABSTRACT: A new perylene diimide (PDI) ligand (1) functionalized with a dipicolylethylenediamine (DPEN) moiety was synthesized and first
used as a colorimetric and fluorometric dual-channel sensor to specifically detect the presence of Cu2+ over a wide range of other cations. The solution of 1 (10 μmol/L) upon addition of Cu2+ displayed distinguishing pink color compared with other cations including K+, Ni2+, Ca2+, Mn2+, Na+, Sr2+, Zn2+, Co2+, Cd2+, Mg2+, Cr3+, Ag+, and Ba2+, indicating the sensitivity and selectivity of 1 to Cu2+. Thus, the advantage of this assay is that naked-eye detection of Cu2+ becomes possible. Moreover, among these metal ions investigated, only Cu2+ quenched more than half fluorescent intensity of 1. The ESI-TOF spectrum of a mixture of 1 and CuCl2 in combination of the fluorescence titration spectra of 1 (10 μmol/L) upon addition of various amounts of Cu2+ revealed the formation of a 2:1 metal-ligand complex through the metal coordination interaction.
Science in China Series B Chemistry 04/2012; 52(4):518-522. · 1.20 Impact Factor
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ABSTRACT: We have developed a synthetic strategy to selectively incorporate the imidazole ring into the 1,1'-bi-2-naphthol (BINOL) skeleton at the different position. The resulting conformationally rigid BINOL-based diimidazolyl ligands bearing both hydrogen-bond-acceptors and -donators can self-assemble into homochiral channel-like mono-component organic frameworks via intermolecular O-H···N hydrogen bonds between the phenolic hydroxyl group and the N2 or N4 atom of the imidazole ring.
Organic & Biomolecular Chemistry 03/2011; 9(8):2618-21. · 3.70 Impact Factor
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ABSTRACT: Self-assembly of the conformationally flexible bismethylimidazolyl ligands with Pd(OAc)(2) is described. Depending on whether the ligands provide the hydrogen bonding donor, a switching of metal-organic vesicles to globular networks gelating solvents is achieved. The metallogels exhibit catalytic activity for the cross-coupling of indole with phenyl boronic acid.
Chemical Communications 06/2010; 46(22):3938-40. · 6.17 Impact Factor
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ABSTRACT: A type of 1,1'-binaphthyl-based imidazolium chemosensor module has been synthesized for the highly selective recognition of tryptophan (Trp) among the eleven alpha-amino acids investigated in aqueous solutions via synergistic effects of multiple hydrogen bonding and electrostatic interactions. These results have demonstrated that the C-2 hydrogen atom of the imidazolium ring plays a key role as a hydrogen bond donor. The UV/vis, fluorescence and mass spectral studies have indicated that a 1 : 1 complex is formed between the host and tryptophan. The binding affinity and selectivity of the cleft-like receptor (R)- with l-Trp are superior to those of (R)-. In spite of an inferior selectivity towards various aromatic amino acids, the macrocyclic (R)- displays a remarkable enantiodiscrimination for the two enantiomers of tryptophan with a K(D)/K(L) value as high as 6.2.
Organic & Biomolecular Chemistry 01/2010; 8(2):339-48. · 3.70 Impact Factor
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Angewandte Chemie International Edition 07/2009; 48(27):4884. · 13.45 Impact Factor
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Angewandte Chemie International Edition 02/2008; 47(30):5646-9. · 13.45 Impact Factor
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ABSTRACT: A monometallic bifunctional catalyst, in which only one imidazolyl moiety is directly attached at the 3-position of a binaphthol moiety, has been developed. The ligand (R)-1, which lacks C2-symmetry and flexible linkers, in combination with Ti(OiPr)4, has been demonstrated to promote the enantioselective cyanation of aldehydes with trimethylsilylcyanide (TMSCN), giving excellent enantioselectivities of up to 98 % ee and high yields of up to 99 %. The use of this bifunctional catalytic system obviates the need for additives and is extremely simple as the reagents are added in one portion at the beginning of the reaction. The protocol has been found to tolerate a relatively wide range of aldehydes when 10 mol % of the (R)-1/Ti(OiPr)4 complex is deployed in CH2Cl2 at -40 degrees C, the conditions which proved most practical and effective. The asymmetric cyanations also proceeded with lower catalyst loadings (5 mol %, or even 2 mol %), still giving satisfactory enantiomeric excesses and yields. Interestingly, the use of freshly distilled TMSCN dried over CaH2 gave a low enantioselectivity and only a moderate yield of the adduct as compared with direct use of the commercial reagent. The results of 13C NMR spectroscopic studies implicate HCN as the actual reactive nucleophile.
Chemistry 02/2008; 14(7):2223-31. · 5.93 Impact Factor
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Chemistry 01/2008; 14(7):2223 - 2231. · 5.93 Impact Factor
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ABSTRACT: The dual Lewis acid/base catalytic system, generated from N-methylimidazole (NMI), (R)-1,1'-bi-2-naphthol [(R)-BINOL], and Ti(OiPr)4, effectively catalyzes the enantioselective alkynylation of aldehydes in the presence of Et2Zn in good yields and excellent enantioselectivities of up to 94% ee at room temperature. The mild reaction conditions make it possible to use functional alkynes in this asymmetric addition.
The Journal of Organic Chemistry 08/2007; 72(14):5457-60. · 4.45 Impact Factor
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Annalen der Chemie und Pharmacie 01/2006; 2006(5):1109 - 1112. · 3.10 Impact Factor
