- The effect of 4-halogenobenzoate ligands on luminescent and structural properties of lanthanide complexes: Experimental and theoretical approaches
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The ligands 4-fluorobenzoate (4-fba), 4-chlorobenzoate (4-cba), 4-bromobenzoate (4-bba) and 4-iodobenzoate (4-iba) were chosen in order to synthesize europium(iii), gadolinium(iii) and terbium(iii) complexes and compare the effect of halogens on their phy
- Monteiro, Jorge H. S. K.,De Bettencourt-Dias, Ana,Mazali, Italo O.,Sigoli, Fernando A.
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- Synthesis and characterization of new tetra-substituted porphyrins with exo-donor carboxylic groups as building blocks for supramolecular architectures. Catalytic and structural studies of their metalated derivatives
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We report herein the synthesis of the porphyrins 5,10,15,20-tetrakis(4- carboxybiphenyl)-porphyrin (H2TCBP) and 5,10,15,20-tetrakis(4- carboxy-2,6-dimethylbiphenyl)porphyrin (H2TCDMBP) bearing diphenyl units on meso-positions, and of
- Carlucci, Lucia,Ciani, Gianfranco,Maggini, Simona,Proserpio, Davide M.,Ragaini, Fabio,Gallo, Emma,Ranocchiari, Marco,Caselli, Alessandro
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experimental part
p. 804 - 814
(2011/09/15)
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- Electronic and steric effects: How do they work in ionic liquids? the case of benzoic acid dissociation
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(Figure Presented) The need to have a measure of the strength of some substituted benzoic acids in ionic liquid solution led us to use the protonation equilibrium of sodium p-nitrophenolate as a probe reaction, which was studied by means of spectrophotometric titration at 298 K. In order to evaluate the importance of electronic effect of the substituents present on the aromatic ring, both electron-withdrawing and -donor substituents were taken into account. Furthermore, to have a measure of the importance of the steric effect of the substituents both para- and ortho-substituted benzoic acids were analyzed. The probe reaction was studied in two ionic liquids differing for the ability of the cation to give hydrogen bond and π-π interactions, namely [bm 2im][NTf2] and [bmpyrr][NTf2]. Data collected show that benzoic acids are less dissociated in ionic liquid than in water solution. Furthermore, the equilibrium constant values seem to be significantly affected by both the nature of ionic liquid cation and the structure of the acid. In particular, the ortho-steric effect seems to operate differently in water and in the aromatic ionic liquid, determining in this solvent medium a particular behavior for ortho-substituted benzoic acids.
- D'Anna, Francesca,Marullo, Salvatore,Vitale, Paola,Noto, Renato
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experimental part
p. 4828 - 4834
(2010/10/04)
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- CLEAVAGE OF THE PHENACYL ESTERS OF CARBOXYLIC AND THIOCARBOXYLIC ACIDS BY METAL ALKOXIDES
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During the cleavage of phenacyl esters with general formula XC6H4COCH2OCOR by metal alkoxides in alcohols and in ether-alcohol solutions the acids, esters, and ethers are formed as a result of cleavage of the C-C bond.The solvent participates in the formation of the ether and gives rise to transesterification of RCOOCH3 with catalytic participation of the metal alkoxide.The reactivity of the phenacyl esters of the thio acids is much higher.Before dissociation the esters of substituted benzoins C6H5COCH(OCOCH3).C6H4X-4 undergo irreversible rearrangement with the formation of isomeric products.
- Morozov, A. A.
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p. 1138 - 1143
(2007/10/02)
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