- New polynuclear compounds based on N-benzyliminodipropionic acid: solution studies, synthesis, and X-ray crystal structures
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Three new polynuclear compounds based on a dicarboxylic acid ligand are reported. In particular, two Cu(II) coordination compounds, [Cu2(H2O)6(Hbzlidp)2](CF3SO3)2·2H2O (1) and [Cu(NO3)(Hbzlidp)]∞ (2) (bzlidp2??=?N-benzyliminodipropionate anion), and a Ni(II) dinuclear compound, [Ni2(H2O)4(bzlidp)2] (3), were synthesized and characterized by IR spectroscopy, elemental analysis and single crystal X-ray diffraction. Different structures were obtained depending on the reaction conditions. The structural analyses reveal that 1 was formed by dinuclear [Cu2(H2O)6(Hbzlidp)2]2+ units built by two copper(II) ions joined through two Hbzlidp? ligands, while 2 was formed by pairs of Cu(II) centers bridged by four syn,syn carboxylate groups to generate “paddle wheel” units. The dinuclear copper units are arranged in a rhombus type grid, in a 2-D layer structure. In both cases, the N was protonated and not coordinated to the metal center. Compound 3 was formed by [Ni2(H2O)4(bzlidp)2] neutral dinuclear units, with octahedral Ni(II) centers. Solution studies of the ligand–M(II) systems (M(II)?=?Mn, Co, Ni, Cu, Zn, Cd, and Pb) were also carried out.
- Bra?a, Emiliano,Qui?one, Delfina,Martínez, Sebastián,Grassi, Joaquín,Carrera, Ignacio,Torres, Julia,González-Platas, Javier,Seoane, Gustavo,Kremer, Carlos,Mendoza, Carolina
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- Natural phosphate modified with lithium nitrate: A new efficient catalyst for the construction of carbon-carbon, carbon-sulfur, and carbon-nitrogen bonds
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The addition of small amounts of lithium nitrate to natural phosphate followed by calcination gives a new catalyst Li/NP (weight ratio LiNO3/NP = 1/15). This material showed catalytic activity in the Michael addition of amines, mercaptans, and active methylene compounds to chalcone derivatives with high yields under mild reaction conditions. Li/NP is used as the catalyst for a facile synthesis of -amino acids, -sulfur acids, and 4 H-chromenes under heterogeneous conditions. The usual, undesirable byproducts from the Michael condensation such as 1,2-addition, bis-addition, and polymerization compounds are not observed with this method. The work-up procedure is simplified by simple filtration with the use of Li/NP.
- Zahouily, Mohamed,Mounir, Bahija,Cherki, Hind,Bahlaouan, Bouchaib,Rayadh, Ahmed,Sebti, Said
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p. 1203 - 1217
(2008/02/02)
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- Natural phosphate and potassium fluoride doped natural phosphate: Efficient catalysts for the construction of a carbon-nitrogen bond
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The application of natural phosphates doped with potassium fluoride as heterogeneous catalysts for the Michael addition of aromatic and aliphatic amines to α,β-unsaturated carbonyl compounds is presented. The natural phosphate catalyst can be regenerated and reused without loss of activity, which makes it an attractive alternative to homogeneous basic reagents. Doping natural phosphate with potassium fluoride significantly enhances the rate and yield of the reaction.
- Zahouily, Mohamed,Bahlaouan, Bouchaib,Rayadh, Ahmed,Sebti, Sa?d
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p. 4135 - 4138
(2007/10/03)
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