Dendrimers, carboxylate-terminated

The use of unmodified LDH for direct anion exchange with polymeric materials has also been reported. For example, Yang and coworker [72] carried out intercalation of poly(ethylene oxide) sulfate and poly(ethylene glycol) within Mg - Al LDH by aging a polymer/LDH aqueous suspension at 65 °C for 4 days. Costa and coworkers [73] prepared nanocomposites through intercalation of dendrimers (carboxylate-terminated polyamidoamide) into LDH. 

Fig. 16.10 Reaction scheme for immobilization of DNA onto functionalized Si02 substrates. Plasma treated Si02 substrates are denoted as Si OH, APTMS functionalized substrates are denoted as Si NH2, dendrimer functionalized substrates are denoted as Si G(4.5)COOH, and substrates to which DNA capture probes have been immobilized are denoted as Si DNA. Inset Repeat unit of PAMAM dendrimer possessing terminal carboxylic acid functionality...

Amine-terminated, full-generation PAMAM and PPI dendrimers, as well as carboxylate-terminated half-generation PAMAM dendrimers, can directly bind metal ions to their surfaces via coordination to the amine or acid functionality. A partial hst of metal ions that have been bound to these dendrimers in this way includes Na+, K+, Cs+, Rb+, Fe +, Fe +, Gd +, Cu+, Cu +, Ag+, Mn +, Pd, Zn, Co, Rh+,Ru +,andPt + [18,19,27,36,54,82-96]. Tuxro et al.have also shown that the metal ion complexes, such as tris(2,2 -bipyridine)ruthenium (Rulbpylj), can be attached to PAMAM dendrimer surfaces by electrostatic attraction [97]. A wide variety of other famihes of dendrimers have also been prepared that bind metal ions to their periphery. These have recently been reviewed [3]. Such surface-bound metal ions can be used to probe dendrimer structure using optical spectroscopy, mass spectrometry, and electron paramagnetic resonance (EPR) [86-88,90,97-99]. 

Poly(3inido amine) (PAMAM) Dendrimers. These dendrimers have a hydro-phihc polyamide interior that is relatively open to solvent, in contrast to a micellar assembly. Yet, the picture of a unimolecular micelle also emerged for a generation 4.5 PAMAM dendrimers having sodium carboxylate terminal groups (Fig. 11.4). 

Figure 11.4 Generation 4.5 poly(amido amine) dendrimer having sodium carboxylate terminal groups.

In contrast, neutral hydroxy-terminated dendrimers generally exhibit hydrodynamic volumes that are invariant with pH (Young et al. 1994). The stmcture of carboxyl-terminated arborol dendrimers has been extensively characterized by... 

Huang QR, Dubin PL, Lai J, Moorefield CN, Newkome GR. SmaU-angle neutron scattering studies of charged carboxyl-terminated dendrimers in solutions. Langmuir 2005 21 2737-2742. 

Miura N, Dubin PL, Mooiefield CN, Newkome GR. Complex formation by electrostatic interaction between carboxyl-terminated dendrimers and oppositely charged polyelectrolytes. Langmuir 1999 15 4245-4250. 

Seyrek E, Dubin PL, Newkome GR. Effect of electric field on the mobility of carboxyl-terminated dendrimers. J Phys Chem B 2004 108 10168-10171. 

NaPGA) and amine-terminated PAMAM dendrimers [102-105], The flexible NaPGAs are possible to interact not only with protonated primary amines in the periphery of a dendrimer but also with tertiary amines in its interior. Opposite combination of the complex, which is stimulated by the electrostatic interaction, was formed between cationic synthetic polyelectrolyte, poly(dial-lyldimethylammonium chloride), and anionic carboxyl-terminated PAMAM dendrimers [106-109],... 

Wade. D.A. Torres. P.A. Tucker, S.A. Spectrochemical investigations in dendritic media Evaluation of nitrometh-ane as a selective fluorescence quenching agent in aqueous carboxylate-terminated polyamido amine (PAMAM) dendrimers. Anal. Chim. Acta 1999.397, 17-31. 

Fig. 26 The saturated-shell architecture approach to covalent megamer synthesis. All surface dendrimers are terminated with carboxylic acid [165]...

An interesting and novel potential use of dendrimers has been described by Menzel and co-workers who have developed photoluminescent dendrimers for fingerprint detection [101]. Amine terminated PAMAM dendrimer nanocomposites with cadmium sulfide were synthesised by the addition of methanolic solutions of cadmium nitrate and sodium sulfide to a methanolic solution of the dendrimer. Amine terminated dendrimers were selected so that they could form amide bonds with the carboxylic acids abundant in fingerprint residues. When bound to the fingerprint residues, the dendrimer composites serve as photoluminescent markers that aid detection. 

Huang, Q. R., P. L. Dubin, C. N. Moorefield, and G. R. Newkome. 2000. Counterion binding on charged spheres Effect of pH and ionic strength on the mobility of carboxyl-terminated dendrimers. Journal of Physical Chemistry B 104 (5) 898-904. 

Titration has been used to obtain information about carboxylic acid-terminated dendrimers. In one study of this type of dendrimer, the various generation... 

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