Browsing by Author "Jessop, Ignacio A."

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    A new porous organic polymer containing Troger's base units: Evaluation of the catalytic activity in Knoevenagel condensation reaction
    (2021) Rodriguez-Gonzalez, Fidel E.; Niebla, Vladimir; Velazquez-Tundidor, M. V.; Tagle, Luis H.; Martin-Trasanco, Rudy; Coll, Deysma; Ortiz, Pablo A.; Escalona, Nestor; Perez, Edwin; Jessop, Ignacio A.; Terraza, Claudio A.; Tundidor-Camba, Alain
    The classic Tro center dot ger's base polymerization of a diamine and dimethoxymethane with trifluoroacetic acid as catalyst generated a Tro center dot ger's base-type polymer (TBP), which exhibited the absolute insolubility in a variety of organic solvents because of its highly aggregated model. A new porous organic polymer was obtained by a simple Tro center dot ger's base polymerization reaction between a diamine and formaldehyde in the form of acetal in the presence of trifluoroacetic acid as catalyst. Tro center dot ger's base-type polymer (TBP) resulted insoluble in a wide range of organic solvents due to its rigid and aromatic structure. TBP was characterized spectroscopically (FT-IR), thermally and morphologically. As result, a thermostable and amorphous polymer bearing pores ranging between 50 and 300 nm and macro-voids of up to 12 mu m was obtained. Due to the insolubility of the TBP, it was tested as a metal-free heterogeneous catalyst in the Knoevenagel condensation reaction, showing a high efficiency. For this, the optimal catalyst load, reaction time and reuse of the catalyst were studied using benzaldehyde and malononitrile as substrates. Furthermore, aldehydes with variable chain sizes and ethyl cyanoacetate replacing malononitrile were tested as substrate with a high percent of conversion (97-99%).
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    Comparison between poly(azomethine)s and poly(p-phenylvinylene)s containing a di-R-diphenylsilane (R = methyl or phenyl) moiety. Optical, electronic and thermal properties
    (2021) Sobarzo, Patricio A.; Mariman, Andrea P.; Sanchez, Christian O.; Hauyon, Rene A.; Rodriguez-Gonzalez, Fidel E.; Medina, Jean; Jessop, Ignacio A.; Recabarren-Gajardo, Gonzalo; Tundidor-Camba, Alain; Terraza, Claudio A.
    Two new silicon-containing poly(azomethine)s (PAzM-Me and PAzM-Ph) and two new silicon-containing poly(pphenylvinylene)s (PPVSi-Me and PPVSi-Ph) were obtained from 4',4'''-(dimethylsilanediyl)bis([1,1 '-biphenyl]-4-carbaldehyde) and 4',4'''-(diphenyl silanediyl)bis([1,1 '-biphenyl]-4-carbaldehyde) with p-phenylendiamine for PAzMs or phenylenebis(methylene))bis(triphenylphosphonium) bromide for PPVSis. All polymers were structurally characterized by FT-IR, NMR and elemental analysis. The materials showed a high thermal stability (501-538 degrees C) with the TPS-core increasing this parameter. The absorption and emission of PAzMs and PPVSis were closely related with the nature of the silane-core in the backbone. All samples showed wide-band gaps where the TPS-core-based materials evidenced the lower energy transitions; PAzM-Ph (2.83 eV) and PPVSi-Ph (2.81 eV). This work lay the groundwork for new architectures of silane-based poly(azomethine)s and poly(p- phenylvinylene)s derivatives for potential optoelectronic applications.
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    Computational chemistry advances on benzodithiophene-based organic photovoltaic materials
    (TAYLOR & FRANCIS INC, 2022) Angel, Felipe A.; Camarada, Maria B.; Jessop, Ignacio A.
    Over the past years, highly efficient conjugated polymers and small molecules have led to the development of organic photovoltaics (OPVs) as a promising alternative to conventional solar cells. Among the many designs, benzodithiophene (BDT)-based systems have achieved outstanding power conversion efficiency (PCE), breaking the 10% PCE barrier in the single-junction OPV devices. However, the precise molecular design of BDT-based materials to tune optical and electrochemical properties, morphology, and interaction between layers remains a challenge. At this point, computational chemistry provides an excellent option to supplement traditional characterization methods and, as a vital tool for designing new systems, understanding their structure-property relationship, predicting their performance, and speeding up OPV research. Hence, this review focused on advances in theoretical simulations of BDT-based OPVs during the last decade. First, a brief introduction of theoretical methodologies, including molecular dynamics simulations and quantum-chemical methods, is given. Then, selected examples of BDT-based materials that have shown great potential to generate high-efficiency devices were reviewed, considering DFT, deterministic, and stochastic methods. Finally, prospects and challenges are pointed out for the future design of improved OPVs.
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    New Benzotriazole and Benzodithiophene-Based Conjugated Terpolymer Bearing a Fluorescein Derivative as Side-Group: In-Ternal Forster Resonance Energy Transfer to Improve Organic Solar Cells
    (MDPI, 2022) Jessop, Ignacio A.; Cutipa, Josefa; Perez, Yasmin; Saldias, Cesar; Fuentealba, Denis; Tundidor-Camba, Alain; Terraza, Claudio A.; Camarada, Maria B.; Angel, Felipe A.
    A new benzodithiophene and benzotriazole-based terpolymer bearing a fluorescein derivative as a side group was synthesized and studied for organic solar cell (OSC) applications. This side group was covalently bounded to the backbone through an n-hexyl chain to induce the intramolecular Forster Resonance Energy Transfer (FRET) process and thus improve the photovoltaic performance of the polymeric material. The polymer exhibited good solubility in common organic chlorinated solvents as well as thermal stability (TDT10% > 360 degrees C). Photophysical measurements demonstrated the occurrence of the FRET phenomenon between the lateral group and the terpolymer. The terpolymer exhibited an absorption band centered at 501 nm, an optical bandgap of 2.02 eV, and HOMO and LUMO energy levels of -5.30 eV and -3.28 eV, respectively. A preliminary study on terpolymer-based OSC devices showed a low power-conversion efficiency (PCE) but a higher performance than devices based on an analogous polymer without the fluorescein derivative. These results mean that the design presented here is a promising strategy to improve the performance of polymers used in OSCs.
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    New Hybrid Copper Nanoparticles/Conjugated Polyelectrolyte Composite with Antibacterial Activity
    (2021) Jessop, Ignacio A.; Perez, Yasmin P.; Jachura, Andrea; Nunez, Hipolito; Saldias, Cesar; Isaacs, Mauricio; Tundidor-Camba, Alain; Terraza, Claudio A.; Araya-Duran, Ingrid; Camarada, Maria B.; Carcamo-Vega, Jose J.
    In the search for new materials to fight against antibiotic-resistant bacteria, a hybrid composite from metallic copper nanoparticles (CuNPs) and a novel cationic pi-conjugated polyelectrolyte (CPE) were designed, synthesized, and characterized. The CuNPs were prepared by chemical reduction in the presence of CPE, which acts as a stabilizing agent. Spectroscopic analysis and electron microscopy showed the distinctive band of the metallic CuNP surface plasmon and their random distribution on the CPE laminar surface, respectively. Theoretical calculations on CuNP/CPE deposits suggest that the interaction between both materials occurs through polyelectrolyte side chains, with a small contribution of its backbone electron density. The CuNP/CPE composite showed antibacterial activity against Gram-positive (Staphylococcus aureus and Enterococcus faecalis) and Gram-negative (Escherichia coli and Salmonella enteritidis) bacteria, mainly attributed to the CuNPs' effect and, to a lesser extent, to the cationic CPE.
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    Synthesis of dimethyl- and diphenylsilane-based oligo(azine)s: Thermal, optical, electronic, and morphological properties
    (2022) Sobarzo, Patricio A.; Jessop, Ignacio A.; Perez, Yasmin; Hauyon, Rene A.; Velazquez-Tundidor, Maria V.; Medina, Jean; Gonzalez, Alexis; Garcia, Luis E.; Gonzalez-Henriquez, Carmen M.; Coll, Deysma; Ortiz, Pablo A.; Tundidor-Camba, Alain; Terraza, Claudio A.
    Four new oligo(azine)s were synthesized from dimethyldiphenylsilane and tetraphenylsilane core-based dialdehydes and hydrazine by high-temperature polycondesation and proposed as materials for optoelectronic applications. The oligo(azine)s were characterized by EA, FT-IR, and NMR. Although most of samples were poorly soluble, TPS-containing PAZ-4 was soluble in aprotic polar solvents. According to SEC and FT-IR studies, the samples were oligomers with up to five repeating units long. TGA showed highly stable samples with TDT10% over 420 degrees C except for PAZ-1 that contains a DMS core along with phenyl units, and thus, the lowest carbon content in the series. From DSC analysis, the substitution of phenyl groups in PAZ-1/3 by biphenyl moieties in PAZ-2/4 allowed to obtain oligo(azine)s with lower T-g values. PAZ-4 showed a UV-A absorption with optical band-gap values of 2.91 and 2.65 eV from UV-vis (solution) and DRS (films), respectively. PL analysis showed a violet emission. PAZ-4 showed resistivity of 29.24 omega cm, similar to wide-band gap materials. Their contact angle measurements showed a critical surface tension of 42.29 dynes/cm, revealing its hydrophobicity. AFM analysis indicated that the PAZ-4 films had homogeneous surfaces. Young's modulus close to 4.46 GPa was established by microindentation for the PAZ-4 thin-films.
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    Tetraphenylsilane-based oligo(azomethine)s containing 3,4-ethylenedioxy- thiophene units along their backbone: Optical, electronic, thermal properties and computational simulations
    (2022) Sobarzo, Patricio A.; Gonzalez, Alexis; Jessop, Ignacio A.; Hauyon, Rene A.; Medina, Jean; Garcia, Luis E.; Zarate, Ximena; Gonzalez-Henriquez, Carmen; Schott, Eduardo; Tundidor-Camba, Alain; Terraza, Claudio A.
    A series of three new oligo-poly(azomethine)s (o-PAzMs) were successfully synthesized, incorporating tetra-phenylsilane (TPS) and 3,4-ethylenedioxythiophene (EDOT) moieties with Mn and Mw between 3.9 and 5.4 kDa and 8.3-11.6 kDa, respectively. The silylated o-PAzMs were highly soluble in low-boiling point solvents such as CHCl3, THF, and CH2Cl2. All three materials are highly thermally stable, with onset temperatures of degradation of at least 250 degrees C and with TDT10% between 340 and 460 degrees C. The glass transition temperature values agree with the flexibility of the repetitive units and showed values between 125 and 155 degrees C. The absorption and emission of the o-PAzMs were observed in the blue-violet UV-vis region (350-550 nm) with moderate Stokes shifts (48-71 nm). The oligomers are it-conjugated wide-band gap materials (2.83-2.73 eV), where the high electronic tran-sitions would be associated with disruption of it-conjugation, which is promoted by the TPS core and (d-p)it orbital interactions. This disruption controls the effect from the EDOT unit rich donor on HOMO (-5.79 eV to-5.71 eV) and LUMO (-2.98 eV to-2.89 eV) energy values. Furthermore, DFT and TDDFT calculations were performed to theoretically characterize the observed UV-Vis transitions and frontier molecular orbitals (MOs) energies.
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    Thiophene- and bithiophene-based π-conjugated Schiff base oligomers containing binaphthalene moieties in the backbone. Properties and computational simulations
    (2024) Gonzalez, Alexis F.; Mariman, Andrea P.; Hauyon, Rene A.; Pavez-Lizana, Danitza; Saldias, Cesar; Schott, Eduardo; Zarate, Ximena; Garcia, Luis; Gonzalez-Henriquez, Carmen M.; Jessop, Ignacio A.; Tundidor-Camba, Alain; Sobarzo, Patricio A.; Terraza, Claudio A.
    New pi-conjugated Schiff base oligomers (o-AZdAN1Th and o-AZdAN2Th) based on a binaphthalene core and containing thiophene or bithiophene units in their backbone were synthesized from the reaction between [1,1 '-binaphthalene]-4,4 '-diamine with thiophene-2,5-dicarbaldehyde and [2,2 '-bithiophene]-5,5 '-dicarbaldehyde by a high-temperature polycondensation method. These new materials were slightly soluble in non-protic polar solvents, such as chloroform and dichloromethane. From GPC analysis of the CHCl3-soluble fraction, o-AZdAN1Th was found to be a tetramer, whereas o-AZdAN2Th was a trimer with 1.4 kDa and 1.3 kDa average molecular weight (Mn), respectively. Both samples exhibited high thermal stability with T5% values of 452 degrees C and 456 degrees C and relatively high Tg values of 346 degrees C and 384 degrees C, for o-AZdAN1Th and o-AZdAN2Th, respectively. The samples showed absorptions in the deep-blue (o-AZdAN1Th) and blue (o-AZdAN2Th) regions of the visible spectrum, and emission responses at 387 nm and 447 nm, respectively, with moderate Stokes shifts (77-95 nm). Their optical and electronic properties were similar to those described for thiophene-based materials, with optical bandgap values close to 2.4 eV. HOMO energy values of -5.98 and -5.95 eV and LUMO energy values of -3.87 eV and -3.84 eV were obtained for o-AZdAN1Th and o-AZdAN2Th, respectively. Theoretical DFT and TD-DFT calculations were used to compare the effect of increasing thiophene units along the backbone for the real and also theoretical o-AZdANxTh samples (x = 3 and 4 thiophene units). According to our study, these two new thiophene-based can be proposed for optoelectronic applications.