Publications by authors named "Gabino A Carriedo"

Article Synopsis
  • Researchers successfully synthesized highly polarized lithium phosphides (LiPR) using deep eutectic solvents, showcasing a sustainable method at room temperature without a protective atmosphere.
  • The process involved the reaction of aliphatic and aromatic secondary phosphines (HPR) with n-BuLi, which allowed for rapid generation of LiPR.
  • The resulting LiPR was then quickly and selectively added to aldehydes or epoxides, producing α- or β-hydroxy phosphine oxides under standard air conditions, challenging traditional limitations in polar organometallic chemistry.
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During the last number of years a variety of crystallization-driven self-assembly (CDSA) processes based on semicrystalline block copolymers have been developed to prepare a number of different nanomorphologies in solution (micelles). We herein present a convenient synthetic methodology combining: (i) The anionic polymerization of 2-vinylpyridine initiated by organolithium functionalized phosphane initiators; (ii) the cationic polymerization of iminophosphoranes initiated by -PRCl; and (iii) a macromolecular nucleophilic substitution step, to prepare the novel block copolymers poly(bistrifluoroethoxy phosphazene)--poly(2-vinylpyridine) (PTFEP--P2VP), having semicrystalline PTFEP core forming blocks. The self-assembly of these materials in mixtures of THF (tetrahydrofuran) and 2-propanol (selective solvent to P2VP), lead to a variety of cylindrical micelles of different lengths depending on the amount of 2-propanol added.

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Article Synopsis
  • - The use of polar organolithium reagents in synthesis is challenging for sustainable chemistry due to their high reactivity, which necessitates strict conditions like low temperatures and inert atmospheres.
  • - A new method utilizing deep eutectic solvents (DESs) has been developed, allowing anionic polymerization of olefins (like styrenes and vinylpyridines) under more environmentally friendly conditions without needing a protective atmosphere.
  • - The process yields high-quality polymers (up to 90% yield and low polydispersities) and shows that the polystyryl lithium intermediates remain stable in the DES medium, making it possible to produce well-defined block-copolymers.
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The direct chemical functionalization of poly(spirophosphazene) [NP(O C H )] (1) can be performed by the lithiation of the aromatic rings at low temperature using Schlosser's base (Li Bu/KO Bu or "superbase"), and the subsequent reaction with various electrophiles such as ClSiMe , ClPPh , or MeOB(O C H ) (MeOBpin). The functionalized polymers, isolated in very high yields (>90%) and without degradation of the polymeric chains, have an average degree of substitution per repeat unit ranging from 0.3 (random copolymers) to a maximum of 1.

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We herein report the formation of two complex nanostructures, toroidal micelles and bicontinuous nanospheres, by the self-assembly of the single structurally simple crystalline-b-coil diblock copolymer poly[bis(trifluoroethoxy)phosphazene]-b-poly(styrene), PTFEP-b-PS, in one solvent (THF) and without additives. The nature of these nanostructures in solution was confirmed by DLS and cryo-TEM experiments. The two morphologies are related by means of a new type of reversible morphological evolution, bicontinuous-to-toroidal, triggered by changes in the polymer concentration.

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The self-assembly in thin films of polyphosphazene block copolymers [N = P(O2C12H8)]n-b-[N = PMePh]m (O2C12H8 = 2,2'-dioxy-1,1'-biphenyl; : n = 50, m = 35; : n = 20, m = 70, and : n = 245, m = 60), having different volume fractions of the rigid [N = P(O2C12H8)]n block, has been studied. BCP spontaneously self-assembled into well-defined round-shaped macroporous films, observing also, as a minor morphology, spherical vesicles in regions where the film was not formed. A detailed study by SEM, TEM and AFM of the structure of the vesicles, the morphology of the pores (inverted mushroom-shaped), and the behaviour of the copolymers with shorter () and longer () [N = P(O2C12H8)]n rigid blocks provided sufficient experimental evidence to propose a vesicle-to-pore morphological evolution as the most likely mechanism to explain the pore formation during the self-assembly of .

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The preparation of long-term-stable giant unilamellar vesicles (GUVs, diameter ≥ 1000 nm) and large vesicles (diameter ≥ 500 nm) by self-assembly in THF of the crystalline-b-coil polyphosphazene block copolymers [N=P(OCH2CF3)2 ]n-b-[N=PMePh]m (4 a: n=30, m=20; 4 b: n=90, m=20; 4 c: n=200, m=85), which combine crystalline [N=P(OCH2CF3)2] and amorphous [N=PMePh] blocks, both of which are flexible, is reported. SEM, TEM, and wide-angle X-ray scattering experiments demonstrated that the stability of these GUVs is induced by crystallization of the [N=P(OCH2CF3)2] blocks at the capsule wall of the GUVS, with the [N=PMePh] blocks at the corona. Higher degrees of crystallinity of the capsule wall are found in the bigger vesicles, which suggests that the crystallinity of the [N=P(OCH2CF3)2] block facilitates the formation of large vesicles.

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A random phosphazene copolymer {[N = P((CH2)7-Br)Ph]0.5[N = PMePh]0.5}n (2) and a block copolyphosphazene {[N = P((CH2)7-Br)Ph]0.

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New advances into the chirality effect in the self-assembly of block copolymers (BCPs) have been achieved by tuning the helicity of the chiral-core-forming blocks. The chiral BCPs {[N=P(R)-O2C20H12](200-x)[N=P(OC5H4N)2](x)}-b-[N=PMePh]50 ((R)-O2C20H12 = (R)-1,1'-binaphthyl-2,2'-dioxy, OC5H4N = 4-pyridinoxy (OPy); x = 10, 30, 60, 100 for 3 a-d, respectively), in which the [N=P(OPy)2] units are randomly distributed within the chiral block, have been synthesised. The chiroptical properties of the BCPs ([α]D vs.

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We describe a new and very versatile method to place chosen chemical functionalities at the edge of the pores of macroporous materials. The method is based on the synthesis and self-assembly of inorganic block copolymers (BCPs) having chiral rigid segments bearing controllable quantities of randomly distributed functional groups. The synthesis of a series of optically active block copolyphosphazenes (PP) with the general formula [N=P(R-O2C20H12)(0.

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Growing complex metallic crystals, supported high index facet nanocrystal composites and tunable porosity metals, and exploiting factors that influence shape and morphology is crucial in many exciting developments in chemistry, catalysis, biotechnology and nanoscience. Assembly, organization and ordered crystallization of nanostructures into complex shapes requires understanding of the building blocks and their association, and this relationship can define the many physical properties of crystals and their assemblies. Understanding crystal evolution pathways is required for controlled deposition onto surfaces.

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A series of optically active helical polyphosphazene block copolymers of general formula R-[N=P(O2C20H12)]n-b-[N=PMePh]m (R-7 a-c) was synthesized and characterized. The polymers were prepared by sequential living cationic polycondensation of N-silylphosphoranimines using the mono-end-capped initiator [Ph3 P=N=PCl3][PCl6] (5) and exhibit a low polydispersity index (ca. 1.

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The intrachain conformation, molecular structure and interchain assembly of isotactic (R)-poly(2,2'-dioxy-1,1'-binaphthyl)phosphazene (P-DBNP) both in the bulk state (I) and in the cast film (II) were studied by molecular dynamics (MD) simulations of models, as implemented by a bias potential for the analysis of the radial distribution function (RDF) obtained from large-angle X-ray scattering (LAXS) data. The microscopic structure and order extension of the polymer changed from I to II, as qualitatively shown in the shapes of their experimentally measured RDF curves. With the use of a bias potential, the MD simulations provided a much more accurate analysis of the models, as seen in the reproduction of the RDFs.

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Stable cyclotriphosphazenes 5 and 6, with three and four carbon radical centers, have been prepared by condensation of (4-hydroxy-2,6-dichlorophenyl)bis(2,4,6-trichlorophenyl)methyl radical (4) with tetrachloro-2,2'-dioxybiphenylcyclotriphosphazene (7). EPR studies of both polyradicals in fluid solution suggest an electronic communication through the PN multiple bonds of the cycle. EPR spectral results in frozen solutions and magnetic susceptibility measurements in the solid are consistent with very weak electron-electron dipolar interactions.

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A simple and convenient one-pot synthesis of THF solutions of high molecular weight poly(dichlorophosphazene) [NPCl(2)](n), or the (15)N isotopomer [(15)NPCl(2)](n), starting directly from PCl(5) and NH(4)Cl or (15)NH(4)Cl in a solution of 1,2,4-trichlorobenzene in the presence of sulfamic acid and calcium sulfate dihydrate, is described. The solutions of [NPCl(2)](n) in THF, which are obtained free of poly(tetrahydrofuran) by preparing them in the presence of K(2)CO(3), can be reacted directly with phenols, biphenols, or even HO-CH(2)CF(3) in the presence of K(2)CO(3) or Cs(2)CO(3) to obtain, after a very simple workup, the corresponding polyphosphazene derivatives almost free of chlorine.

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