Search results for "Polyamin"

Polyaminoazide mixtures for the synthesis of pH-responsive calixarene nanosponges

2019

Two mixtures of polyaminoazides were synthesized by a nucleophilic displacement strategy providing no separation of the components. The mixtures were adequately characterized by means of combined HR-ESIMS, FTIR and NMR techniques and, despite their complexity, they were successfully used to accomplish the subsequent preparation of pH-sensitive calixarene hyper-reticulated nanosponge materials. The desired responsivity to pH variations of the nanosponges obtained was verified by means of absorption tests on a set of organic pollutant model molecules.

Polyaminocyclodextrin nanosponges: synthesis, characterization and pH-responsive sequestration abilities

2016

New pH-responsive nanosponges were obtained by reacting four different polyaminocyclodextrins with heptakis-(6-bromo)-(6-deoxy)-β-cyclodextrin. The materials obtained were characterized by various techniques (FT-IR, potentiometric titration, differential scanning calorimetry (DSC), porosimetry (BET), 13C{1H} CP-MAS NMR). Their adsorption abilities at different pH values were verified towards a suitable set of model guests, and seem mainly controlled by electrostatic interactions, as a function of the protonation/charge status of the polymer matrix. By contrast, data positively point out a lesser importance assumed by the induced-fit effect, important in affecting the formation of host–guest…

Cross-Linked Polyamine from Imidazolium-Based Materials: A Simple Route to Useful Catalytic Materials

2018

Synthesis and protonation behaviour of the macrocycle 2,6,10,13,17,21-hexaaza[22]metacyclophane. Thermodynamic and NMR studies on the interaction of …

1996

Abstract The novel cyclophane receptor 2,6,10,13,17,21-hexaaza[22]metacyclophane (L) has been synthesised and characterised. The acid-base behaviour and interaction with ATP, ADP and AMP have been studied by potentiometry in 0.15 mol dm−3 at 298.1 K and multinuclear NMR. L presents in its protonated forms a molecular organization which enables its multipoint binding with nucleotides. Salt-bridge formation occur between the polyammonium sites of L and the phosphate chain of the nucleotides while π-stacking between the meta-phenylene subunit incorporated in the receptor and the adenine ring of the nucleotides.

Spermidine and morphogenesis in single cell cultures of Sideritis angustifolia lag.

1990

Abstract Single cells from hypocotyl-derived callus of Sideritis angustifolia were evaluated for morphogenesis when cultured in either solidifier or liquid Murashige and Skoog medium supplemented with various concentrations of spermidine, naphthaeneacetic acid (NAA), benzyladenine (BA) and dicyclohexylamine (DCHA). Spermidine (Spd) did not replace the hormonal requirements for cell division and callus formation, but affected growth induced by NAA or BA. This polyamine increased the plating efficiency of cells cultured in the presence of NAA (0.05, 0.54 and 5.40 μM) or BA (0.40, 4.40 and 8.80 μM). In contrast, Spd reduced growth induced by 10.80 μM NAA, optimal auxin concentration for callus…

Cu2+ Coordination Properties of a 2-Pyridine Heptaamine Tripod: Characterization and Binding Mechanism

2009

The synthesis, protonation, and Cu(2+) coordination chemistry of a tripodal heptaamine ligand (L(1)) functionalized with 2-pyridine fragments at the ends of its three branches are reported. L(1) presents six relatively high protonation constants followed by much more reduced constant that as indicated by the UV-vis and NMR data, occur on the pyridine fragments. p[H]-metric, ESI/MS(+), EPR and UV-vis data show that L(1) is able to form mono-, di-, and trinuclear Cu(2+) complexes. Slippage movements and molecular reorganizations have been observed to occur as a function of p[H] in the 1:1 Cu(2+) complexes. The kinetic studies showed that the complex formation is fast and proceeds through a di…

Hydrophilic and hydrophobic copolymers of a polyasparthylhydrazide bearing positive charges as vector for gene therapy

2008

BACKGROUND: The design of polymeric vectors for gene delivery provided with specific properties is one of the most critical aspects for a successful gene therapy. These polymers should be biocompatible as well as able to carry efficiently DNA to target tissues and to transfect it into cells. RESULTS: The formation of complexes of poly[(α,β-asparthylhydrazide)–poly(ethylene glycol)] and poly[(α,β-asparthylhydrazide)–hexadecylamine] copolymers functionalised with glycidyltrimethylammonium chloride (PAHy–PEG-GTA and PAHy–C16-GTA, respectively) with DNA was studied. The effects of the introduction of hydrophilic (PEG) or hydrophobic (C16) moieties on the chains of PAHy–GTA copolymers, such as t…

Synthetic methods for the preparation of polystyrene resins containing chiral polyamine chains

1998

Abstract The preparation of functionalized polystyrene-divinylbenzene resins containing functional groups derived from polyamine aliphatic chains has been studied. Best results are always obtained by direct alkylation of the polyamine with Merrifield's polymers, but double alkylation at both end of the polyamine is observed. The procedure is useful for the preparation of polymer containing different chiral and non-chiral polyamine functionalities.

Binding of acrylic and sulphonic polyanions by open-chain polyammonium cations

2000

Abstract The interactions between some acrylic and sulphonic polyanions and some protonated amines (diamines NH 2 -(CH 2 ) x -NH 2 , x =2,…,10; linear tri-, tetra-, penta- and hexa-amines) were studied potentiometrically in aqueous solution, at 25°C. For both types of polyanions AL 2 H i (L − , monomer of polyanion, A, amine) species are formed, with i =1,…, n ( n =number of amino groups in the amine). The stability of these species is strictly dependent on the polyammonium cation charge, and fairly independent of the type of amine (in diamine species maximum stability is observed for x =4, 5). Acrylic and sulphonic polyanion complexes are considerably stronger than analogous species formed…

Fluorescent Type II Materials from Naphthylmethyl Polyamine Precursors

2004

Speciation studies in aqueous solution on the interaction of Cu2+ and Zn2+ with a series of polyaminic ligands N-naphthalen-1-ylmethyl-N′-{2-[(naphthalen-1-ylmethyl)-amino]-ethyl}-ethane-1,2-diamine (Ll), N-naphthalen-1-ylmethyl-N′-(2-{2-[(naphthalen-1-ylmethyl)-amino]-ethylamino}-ethyl)-ethane-1,2-diamine (L2) and N-naphthalen-1-ylmethyl-N′-[2-(2-{2-[(naphthalen-1-ylmethyl)-amino]-ethylamino}-ethylamino)-ethyl]-ethane-1,2-diamine (L3) containing two naphthylmethyl groups at their termini and N 1-(2-{2-[(naphthalen-1-ylmethyl)-amino]-ethylamino}-ethyl)-ethane-1,2-diamine (L4) containing just one naphthylmethyl group have been carried out at 298.1 K in 0.15 mol dm−3 NaCl. In the case of the …