- An acetoxy functionalized Al(iii) based metal-organic framework showing selective "turn on" detection of perborate in environmental samples
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Here, we have described the design, preparation and detailed characterization of a new acetoxy functionalized aluminium based metal-organic framework (MOF) called CAU-10-OCOCH3 (1) (CAU stands for Christian-Albrechts-University). The desolvated compound was employed for the detection of perborate in a pure aqueous environment. The presented MOF based perborate sensing probe (1) was synthesized by employing 5-acetoxyisophthalic acid and AlCl3·6H2O as the linker molecule and metal salt source, respectively, in DMF/H2O medium at 120 °C for 12 h. The material (1′) showed a very selective fluorescent turn-on response towards perborate in aqueous medium with the coexistence of several competitive analytes. A dramatic increment (65 fold) in emission intensity of the probe was observed within 5 min of the addition of perborate. A chemo-selective reaction between perborate and the acetoxy functionality and subsequent hydrolysis of the acetoxy group to the hydroxy group is the main cause of the turn-on nature of detection. The material showed a detection limit of 1.19 μM. The probe was also applied for the recognition of perborate in several environmental water samples. The material is the first ever MOF based probe for selective detection of perborate. This journal is
- Nandi, Soutick,Reinsch, Helge,Biswas, Shyam
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- Supramolecular self-organization of "janus-like" diblock codendrimers: Synthesis, thermal behavior, and phase structure modeling
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We report on the design and synthesis of three series of segmented amphiphilic block codendrimers. and on their self-organizing behavior in liquid-crystalline mesophases. Connecting two prefunctionalized monodendrons, each differing in their chemical cons
- Bury, Izabela,Heinrich, Benoit,Bourgogne, Cyril,Guillon, Daniel,Donnio, Bertrand
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p. 8396 - 8413
(2007/10/03)
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- Dendrimers with alternating amine and ether generations
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Dendrimers having alternating aryl benzyl ether and tertiary amine generations and up to 16 bis-(2-methoxyethyl)amine end groups and four internal tertiary amines were synthesized by sequential etherification, amidation of secondary amines, and LiAlH
- Pan, Yijun,Ford, Warren T.
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p. 8588 - 8593
(2007/10/03)
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- Process for preparing substituted aryls
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The present invention provides a novel one-step process for preparing substituted aryls which can be used as end-capping monomers for preparing highly branched macromolecule polymers that have highly controlled molecular architectures. The process compris
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- Hyperbranched polymers
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The present invention provides novel highly branched macromolecule polymers that have highly controlled molecular architectures, and having the formula: STR1 wherein R4, R5, and R6 are defined herein.
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- Polyelectrolyte-Catalyzed Acetyl Transfer Reactions. Structure-Reactivity Relationships in the Aminolysis of Phenyl Acetates by Poly(ethyleneimine) and Glycylglycine.
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The aminolysis of a wide series of substituted phenyl acetates by poly(ethyleneimine) (PEI) is studied.Saturation kinetics are observed and the ester-polyamine association equilibrium constants, as well as the rates of decomposition of the resulting intracomplexes, are determined.Unlike the association constants, the rate constants for the reaction of the intracomplex are found to depend on the acidity of the leaving groups.Two Broensted-type relationships are found for anionic and neutral esters having different intercepts but proximate slopes -0.73 and -0.77 respectively, which decrease to lower values with very reactive phenyl acetates.Only one broken Broensted relationship is found for the bimolecular aminolysis by glycylglycine.The results are consistent with the formation of a tetrahedral intermediate by the amino groups of PEI, with a change in the rate-determining step for very reactive esters from the breakdown to the formation of the tetrahedral intermediate.The higher reactivity of PEI, which is more relevant with substrates containing anionic groups, is principally ascribed to the electrostatic polyelectrolyte-substrate binding.A minor role is played by the increase in the acidity of the conjugate acid of the leaving group, i.e. of its leaving ability, caused by the association of the ester with PEI: values of effective molarity in the range of 10 to 15 mol cm-3 are found.
- Arcelli, Antonio,Concilio, Carlo
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p. 201 - 226
(2007/10/02)
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- Effect of Substituents at the 5-Position on the First and Second Dissociation Constants of Isophthalic Acid
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The dissociation constants of benzoic acid and 20 of its meta- or para-substituted derivatives and of isophthalic acid and ten of its 5-substituted derivatives have been measured in 50 wtpercent aqueous methanol.The Hammett ρ value for benzoic acid is 1.28; for isophthalic acid the ρ values are 1.21 (pK1) and 1.20 (pK2).The ?meta values for hydroxy and acetoxy are -0.01 and +0.29, respectively, in this system.Values for ?meta for CO2H and CO2- are calculated to be +0.28 and -0.20, respectively; however there are indications that these values are not completely structure-independent.
- Gumbley, Stewart J.,Stewart, Ross
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p. 529 - 532
(2007/10/02)
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