- Role of hydrophobicity on structure of polymer-metal complexes
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Metal complexation of a series of polymeric gels, with different degrees of ionization, prepared from acrylic acid and acryloyl amino acid monomers (CH2=CHCONH(CH2)nCOOH, where n = 4, 6 and 8), were investigated. The binding of Cu(II) ions to the gels was studied by means of swelling, quantitative determination of the amount of "bound" or complexed Cu(II), and EPR spectroscopy of Cu(II) complexes. Both the amount of Cu(II) and the structure of polymer-Cu(II) complex were influenced by the length of the pendent chain, i.e., "hydrophobicity" of the polymer gels. The metal uptake by the gels increases with increasing "hydrophobicity". Two types of polymer-Cu(II) complexes (monomer and dimer, respectively) were identified by EPR spectroscopy, their concentrations were found to be a function of hydrophilic-hydrophobic balance of the polymer gels.
- Varghese, Shyni,Lele, Ashish K.,Srinivas,Mashelkar, Raghunath A.
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p. 5368 - 5373
(2007/10/03)
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- Synthesis of new cotelomers derived from tris(hydroxymethyl) aminomethane bearing arabinofuranosylcytosine moieties. Preliminary results on their in vitro and in vivo antitumoral activities
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As an approach to the development of drug delivery systems, a new class of low macromolecular carriers called telomers bearing both antitumor agent such as arabinofuranosylcytosine (Ara-C) and galactose moieties were synthesized. These compounds were prep
- Contino, Christiane,Maurizis, Jean-Claude,Ollier, Monique,Rapp, Maryse,Lacombe, Jean-Michel,Pucci, Bernard
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p. 809 - 816
(2007/10/03)
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- Molecular tailoring of thermoreversible copolymer gels: Some new mechanistic insights
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We earlier reported the role of hydrophobic and hydrogen bonding interactions on the transition temperatures of thermoreversible copolymer gels. We show here that the chemical structure of the hydrophobe and its concentration determine the transition temperatures [lower critical solution temperature (LCST)] and the heat of transition of new hydrophobically modified poly(N-isopropyl acrylamide) [PNIPAm] copolymer gels. The gels, prepared by copolymerizing NIPAm monomer with hydrophobic comonomers containing increasing lengths of alkyl side groups and a terminal carboxyl acid group, showed lower LCST and lower heat of transition when compared to pure PNIPAm gel. The experimental results were also compared with theoretical calculations based on a lattice-fluid-hydrogen-bond [LFHB] model. We show experimentally and theoretically that a linear correlation exists between the transition temperature and length of the hydrophobic alkyl side group. Also, in apparent contradiction to previous work, we found a reduction in the heat of transition with increasing hydrophobicity. We propose that the presence of the terminal carboxyl acid group on the hydrophobic side chain of the comonomer prevents the association of water molecules around the hydrophobe, thereby causing a reduction in the heat of transition. The LFHB model supports this argument.
- Badiger,Lele,Bhalerao,Varghese,Mashelkar
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p. 1175 - 1184
(2007/10/03)
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- Synthesis of cotelomers derived from tris(hydroxymethyl)acrylamidomethane (THAM) bearing cytosine arabinoside moieties. Preliminary investigation of their biological activity
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The telomerization of tris(hydroxymethyl)acrylamidomethane (THAM) and cytosine arabinoside (Ara-C) polymerizable derivatives in the presence of transfer reagent such as alkane or perfluoroalkane thiol is described. The cytotoxic activities of these differ
- Contino, Christiane,Ollier, Monique,Maurizis, Jean Claude,Lacombe, Jean Michel,Pucci, Bernard
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p. 9049 - 9052
(2007/10/03)
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