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Dalton Trans ; 47(2): 465-474, 2018 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-29226925


A trifunctional aromatic building block (H2L) containing three different types of functional groups (carboxyl C([double bond, length as m-dash]O)OH, aldehyde C([double bond, length as m-dash]O)H, and O-ether) was applied for the hydrothermal synthesis of two novel lanthanide 2D coordination polymers [Ln(µ-HL)(µ3-L)(phen)]n {Ln = Tb (1) and Eu (2); H2L = 5-methoxy-(4-benzaldehyde)-1,3-benzene dicarboxylic acid; phen = 1,10-phenanthroline}. Both compounds 1 and 2 are isostructural and reveal very complicated 2D metal-organic double layers with the 3,4L27 topology. The presence of free aldehyde groups positioned outside of the double layers opens up a possibility of using them as functional groups toward sensing amines and small organic molecules. The fluorescence measurements for the Tb derivative 1 reveal that it acts as an efficient fluorescence sensor for p-phenylenediamine, benzidine and acetone molecules via a luminescence quenching effect. A similar sensing behavior was observed for the Eu compound 2. Moreover, thin-films of 1-PEG on glass (1-PEG-glass thin-film material) were fabricated and investigated for the detection of amine vapors.

Soft Matter ; 10(31): 5715-23, 2014 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-24985608


Through the rational introduction of the multi self-assembly driving forces and F(-) sensing sites into a gelator molecule, low-molecular-weight organogelators L1 and L2 were designed and synthesized. L1 and L2 showed excellent gelation ability in DMF and DMSO. They could form stable organogels (OGL1 and OGL2) in DMF and DMSO with very low critical gelation concentrations. OGL1 and OGL2 could act as anion-responsive organogels (AROGs). Unlike most of the reported AROGs showing gel-sol phase transition according to the anions' stimulation, OGL1 could colorimetrically sense F(-) under gel-gel states. Upon addition of F(-), OGL1 showed dramatic color changes, while the color could be recovered by adding H(+). Moreover, OGL1 showed specific selectivity for F(-), other common anions and cations could not lead to any similar response. What deserves to be mentioned is that the report on specific sensing of anions under gel-gel states is very scarce. The gel-gel state recognition can endow the organogel OGL1 with the merits of facile and efficient properties for rapid detection of F(-). Therefore, OGL1 could act as a F(-) responsive smart material.

Dalton Trans ; 41(35): 10626-32, 2012 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-22836302


A new 1,3,4-oxadiazole-based fluorescence chemosensor 1, N-(2-ethoxy-2-oxoethyl)-N-(5-(2-hydroxy-3,5-di-tert-butylphenyl)-[1,3,4]oxadiazol-2-yl)glycine ethyl ester, has been designed and synthesized. Its fluorescence properties and selectivity for various metal ions were investigated in detail. A prominent fluorescence enhancement only for Zn(2+) was found in aqueous acetonitrile solution and the response mechanism of 1 was analyzed by time-resolved fluorescence decay and DFT calculations. Furthermore, the fluorescence imaging of Zn(2+) in living cells was successfully applied.

Corantes Fluorescentes/química , Oxidiazóis/química , Espectrometria de Fluorescência , Zinco/análise , Acetonitrilos/química , Células Hep G2 , Humanos , Microscopia de Fluorescência , Água/química
Dalton Trans ; 39(18): 4274-9, 2010 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-20422084


The enantiopure agents d- and l-leucine, selectively bind RR and SS enantiomers from a racemate [Ni(alpha-rac-L)](2+) to give {[Ni(RR-L)(d-HLeu)](ClO(4))(2)}(n) (Delta-) and {[Ni(SS-L)(l-HLeu)](ClO(4))(2)}(n) (Lambda-), respectively, and leave the corresponding uninteracted SS and RR enantiomers of [Ni(alpha-SS-L)](ClO(4))(2) (S-) and [Ni(alpha-RR-L)](ClO(4))(2) (R-). Occasionally, a few crystals of {[Ni(RR-L)(l-HLeu)](ClO(4))(2)}(n) (Delta-) and {[Ni(SS-L)(d-HLeu)](ClO(4))(2)}(n) (Lambda-) were found to have accreted with the crystals of Lambda-/R-, and Delta-/S-, respectively (the yields are less than 2%). The results of X-ray crystal structural analysis reveal that Delta- and Lambda-, S- and R-, and Delta- and Lambda- are enantiomers, in which Delta- and Delta- possess 1D right-handed helical chains, while Lambda- and Lambda- exhibit a motif of 1D left-handed helical chains. The results of DFT calculations reveal that the single-point energies of [Ni(RR-L)(d-HLeu)](2+)/[Ni(SS-L)(l-HLeu)](2+) in Delta-/Lambda- are 582 kJ mol(-1) lower than those of [Ni(RR-L)(l-HLeu)](2+)/[Ni(SS-L)(d-HLeu)](2+) in Delta-/Lambda-, demonstrating the favorable stereo-coordination environments of [Ni(alpha-RR-L)](2+) and [Ni(alpha-SS-L)](2+) towards d and l-HLeu, respectively.

Compostos Macrocíclicos/química , Dicroísmo Circular , Complexos de Coordenação/química , Cristalografia por Raios X , Ligantes , Conformação Molecular , Níquel/química , Estereoisomerismo
Chemistry ; 15(45): 12399-407, 2009 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-19810059


We previously reported that dinuclear copper(II) cryptate [Cu(2)L](4+) cleaves the C-C bond of acetonitrile at room temperature to produce a cyano-bridged dinuclear cryptate and methanol, whereby the reaction mechanism has not yet become clear. We have now systemically investigated this reaction, and four cryptates, [Cu(2)L](ClO(4))(4) (1), [Zn(2)L](ClO(4))(4) (2), [Cu(2)L(H(2)O)(2)](CF(3)SO(3))(4) (5), and [Cu(2)L(OH)(OH(2))](ClO(4))(3) (6) are reported here. Cryptates 1 and 2 can cleave the C--C bonds of acetonitrile, propionitrile, and benzonitrile at room temperature under open atmospheric conditions to give cyano-bridged cryptates [Cu(2)L(CN)](ClO(4))(3) (3) and [Zn(2)L(CN)](ClO(4))(3) (4), respectively, and the corresponding alcohol. In contrast, 5 and 6 do not show any C-C bond activation of nitriles, as the interior axial positions of Cu(II) in 5 and 6 are occupied by water/OH(-). The C-C bond cleavage of (S)-(+)-2-methylbutyronitrile by 2 produced (R)-(-)-2-butanol only; that is, the cleavage reaction proceeds through an S(N)2 pathway (Walden inversion).

Cobre/química , Éteres de Coroa/química , Metais/química , Nitrilos/química , Zinco/química , Cristalografia por Raios X , Estrutura Molecular
Inorg Chem ; 47(8): 3158-65, 2008 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-18318477


The crystal structures of [Co 2L(Cl)](ClO 4) 3 ( 1), [Co 2L(Br)](ClO 4) 3 ( 2), [Co 2L(OH)(OH 2)]I 3 ( 3), and [Co 2L (1)(Cl)](ClO 4) 3 ( 4), the density functional theory calculations, as well as the binding constants of [Co 2L] (4+) toward Cl (-) and Br (-) and of [Co 2L (1)] (4+) toward Cl (-), are reported in this paper (L = N[(CH 2) 2NHCH 2(C 6H 4- p)CH 2NH(CH 2) 2] 3N, L (1) = N[(CH 2) 2NHCH 2(C 6H 4- m)CH 2NH(CH 2) 2] 3N). The rigid dicobalt(II) cryptate [Co 2L] (4+) shows the recognition of Cl (-) and Br (-) but not of F (-) and I (-), because of the size matching to its rigid cavity. We also found that the relative rigid tripodal skeleton of L than that of L (1) results in the higher affinity of [Co 2L] (4+) toward Cl (-). Magnetic susceptibility measurements of 1 and 2 indicate that the two Co(II) atoms in the cryptates are antiferromagnetically coupled through the Cl (-)/Br (-) bridge, with g = 2.19, J = -13.7 cm (-1) for 1, and g = 2.22, J = -17.1 cm (-1) for 2.

Brometos/química , Cloretos/química , Cobalto/química , Éteres de Coroa/química , Ânions/química , Cristalografia por Raios X , Modelos Moleculares , Conformação Molecular , Termodinâmica