Polycarboxylate ligands

Polycarboxylate ligands, 24 768-769 Polycarboxylates, water-soluble, 24 171 Polycarboxylic-acid-containing dyes, 9 480-481... 

In the presence of anions such as phosphate and oxalate, the relaxivity of [Gd(Tex)]2+ is considerably reduced revealing that these anions compete with water for binding to the Gd3+ ion [167,171]. Most likely, texaphyrin complexes self-associate due to strong van der Waals interactions. UV-VIS studies suggest that the aggregates dissociate upon interaction with polyuronides (pectate, alginate), which probably act as polydentate polycarboxylate ligands for the [Gd(Tex)]2+ complexes [173]. 

V in recent and -0.24 V for two-year-old needles, V. myrtillus -0.26 and D.flexuosa -0.165 V), similar to values for polycarboxylate ligands rather than amino acids. This suggests that, for a variety of only loosely related plant species which in addition are supported by quite unlike kinds of mykorrhiza, sigifificant parts of transport and metal fractionation occur beyond the roots (where the doubly labeled C- + N-glycine was recovered (Nasholm et al. 1998)), with the root/shoot interfacial region being the most probable bottleneck or site of control. 

R48 A. Bianchi, L. Calabi, F. Corana, S. Fontana, P. Losi, A. Maiocchi, L. Paleari and B. Valtancoli, Thermodynamic and Stmctural Properties of Gd(III) Complexes with Polyamino-Polycarboxylic Ligands Basic Compounds for the Development of MRI Contrast Agents , p. 309... 

This example emphasizes the potentiality of the benzene polycarboxylate ligands. However some other coordination polymers containing transition metal ions deserve to be highlighted. 

List of lanthanide based coordination polymers with benzene polycarboxylate ligands. Only structurally characterized... 

The reaction of ciprofloxacin (cfH) with metal salts in the presence of aromatic polycarboxylate ligands (or under basic conditions) has been found to give original metal-cfH complexes, for example, [Ba2(cf)2(l,4-bdc)(H20)2] H20 and [Mn(cfH) (1,3-bdc)] (bdc=benzenedicarboxylate). The structure of [Ba2(cf)2(l,4-bdc)(H20)2]-H2O consists of unique two-dimensional arm-shaped layers (Fig. 6), while the second complex contains double-chain-Uke ribbons constructed from [Mn2(cfH)2(C02)2] dimers and 1,3-bdc (Fig. 7) [369],... 

Karuehanon et al. (2012) reported the microwave-assisted S Ar reaction of 2,4,6-trichloro-l,3,5-triazine with various unprotected amino acids for the synthesis of Cj-symmetrical polycarboxylate ligand. These products can be used as structural directing units in metal-organic frameworks. A domestic microwave oven was used as the heating device and the reactions were performed in water. Comparison between the reactions performed under conventional heating and microwave irradiation was made. It was observed that the microwave method takes 20 minutes less time to afford the desired ligands than the conventional method. 

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