Juan T. López Navarrete

University of Asia and the Pacific

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Co-Authors

Juan Casado

Universidad de Málaga

269

V. Hernández

Hartnell College

167

M. Carmen Ruiz Delgado

Universidad de Málaga

115

F. RAMIREZ

Universidad de Málaga

Rocío Ponce Ortiz

Universidad de Málaga

Paula Mayorga Burrezo

Institut de Ciència de Materials de Barcelona

Belén Nieto‐Ortega

Madrid Institute for Advanced Studies

María Moreno Oliva

Universidad de Málaga

J. Orduna

Universidad de Zaragoza

Ted M. Pappenfus

University of Minnesota Morris

Cooperative Institutions

Universidad de Málaga

140

Centre National de la Recherche Scientifique

Consejo Superior de Investigaciones Científicas

Universidad Complutense de Madrid

Northwestern University

Universidad Autónoma de Madrid

Universidad de Zaragoza

University of Castilla-La Mancha

Chinese Academy of Sciences

Universitat de València

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On the Origin of the Chiro-Optical Activity in Supramolecular Assemblies: A Quantum Chemical Study of C₃ Octopolar Systems

Journal of Chemical Theory and Computation (2011)

Belén Nieto‐Ortega Juan Casado Juan T. López Navarrete Gunther Hennrich F. RAMIREZ

First-principles quantum chemical approach has been used to understand the origin of the chiro-optical signal induced by the chiral aggregation of an achiral chromophore. The study was focused in predicting the circular dichroism (CD) spectra of different π-stacked columnar oligomers built with C3 star-shape molecular bricks. We studied the influence of the relevant structural self-assembly parameters on the CD spectra (i.e., the number of units, the rotation angle and the intermonomer distance). A detailed analysis was based on the MO topologies and the magnetic and electric transition dipole moments, the vectors which determine the CD intensities, has been conducted. We have rationalized the influence of the various structural factors of supramolecular self-assemblies in connection with the nature of their CD spectroscopic signal, which provides new avenues for structure-spectroscopic relationships.

Chromophore

Optical Rotation

10.1021/ct200505s

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Citations (5)

Force field and normal coordinate calculations for glutamic acid

Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy (1995)

F. RAMIREZ Juan T. López Navarrete

Force Field

MNDO

Harmonic

10.1016/0584-8539(94)00188-h

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Citations (36)

The Raman fingerprint of cyclic conjugation: the case of the stabilization of cations and dications in cycloparaphenylenes

Chemical Science (2016)

Miriam Peña‐Álvarez M. Carmen Ruiz Delgado Mercedes Taravillo Valentı́n G. Baonza Juan T. López Navarrete

Cyclic conjugation and Biradical formation in charged cycloparaphenylenes are described by Raman spectroscopy and DFT.

10.1039/c6sc00765a

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Citations (26)

On the problem of π electron delocalisation across sp3 carbon atoms introduced as defects in polyacetylene

Solid State Communications (1987)

Juan T. López Navarrete G. Zerbi

Polyacetylene

Quantum chemical

Carbon fibers

10.1016/0038-1098(87)90616-8

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Citations (14)

A molecular viewpoint of lattice dynamics and spectra of conducting polymers

Synthetic Metals (1989)

G. Zerbi Chiara Castiglioni Juan T. López Navarrete Bogang Tian M. Gussoni

Polyacetylene

Lattice (music)

10.1016/0379-6779(89)90715-7

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Citations (69)

Spectroscopic and DFT studies of donor–acceptor molecules containing phenylquinoline and phenothiazine moieties in various redox states

International Journal of Quantum Chemistry (2005)

Rocío Ponce Ortiz Reyes Malavé Osuna M. Carmen Ruiz Delgado Juan Casado Samson A. Jenekhe

Abstract We report the ultraviolet (UV)‐Vis, Fourier transform‐infrared (FT‐IR), and FT‐Raman spectroscopic study of an electrogenerated chemiluminescence (ECL) emitting compound containing two electron‐accepting phenylquinoline end groups covalently attached to an electron‐donating 10‐methylphenothiazine central moiety. The optimized molecular geometry of the neutral compound as determined from quantum chemical density functional theory (DFT)//B3LYP/3‐21G* calculations shows that the phenyl groups appended onto the quinolines are twisted by ≈62° from these moieties. The sulfur atom is also tilted with respect to the plane defined by the phenyl rings of the phenothiazine, in both the neutral and singly oxidized species. The highest occupied molecular orbitals (HOMO) and lowest unoccupied molecular orbitals (LUMO) of the neutral systems partially overlap, so that the lowest‐energy visible absorption band implies a certain degree of charge transfer from the phenothiazine toward the phenylquinolines. In contrast, the removal of the first electron mainly affects the structure and equilibrium charge distribution of the phenothiazine, and much less in those of the quinolines. In addition, the DFT//UB3LYP/3‐21G* topologies of the molecular orbitals around the bandgap region of the radical cation reveal no molecular orbital overlap between the two types of constituent building blocks, thus inhibiting the delocalization of the injected positive charge over the whole molecule. This feature could be in line with the ability of this system to generate localized radical ions capable of displaying chemiluminescence upon annihilation, as previously observed experimentally. The UV‐Vis and FT‐Raman spectra of the singly oxidized species generated upon treatment with FeCl 3 in CH 2 Cl 2 solution have also been recorded. The experimental data were interpreted with the help of DFT calculations. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005

HOMO/LUMO

Radical ion

Electron acceptor

10.1002/qua.20521

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Citations (6)

Electrochemical doping in a series of α, α′-dimethyl end-capped oligothienyls An FT-Raman confirmation of a radical cation generation

Optical Materials (1998)

Juan Casado Toribio F. Otero Shu Hotta V. Hemandez F. RAMIREZ

Radical ion

10.1016/s0925-3467(97)00152-3

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Citations (16)

Efficient π electrons delocalization in α,α′-dimethyl end-capped oligothiophenes: A vibrational spectroscopic study

The Journal of Chemical Physics (1996)

V. Hernández Juan Casado F. RAMIREZ Gianni Zotti Shu Hotta

α,α′-dimethyl substituted oligothiophenes with increasing chain length (from the dimer up to the hexamer) were recently synthesized by chemical methods. In this paper we have investigated the vibrational Fourier transform-IR and Fourier transform-Raman spectra of solid α,α′-dimethyl substituted oligothiophenes in the neutral state. The data are consistent with the existence of a chain-length dependent π electron delocalization: a large frequency dispersion with conjugation length is observed for some Raman and infrared active vibrational modes, particularly at the high-energy side of the aromatic C=C stretching region. Vibrational assignments are proposed for the main vibrational features in the whole spectral range. This vibrational spectroscopic analysis of the solid samples thus becomes a tool for deriving information on the structure of these neutral materials in solution and in the doped state.

10.1063/1.471674

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Citations (140)

Harmonic force field for the glycine molecule by semiempirical methods

Journal of Molecular Structure (1992)

Juan T. López Navarrete J.J. Quirante F. RAMIREZ

Force Field

Harmonic

10.1016/0022-2860(92)85075-r

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Citations (4)

Infrared and multi‐wavelength Raman spectroscopy of regio‐regular P3HT and its deutero derivatives

Journal of Raman Spectroscopy (2017)

Luigi Brambilla Cristina Capel Ferrón Matteo Tommasini Kunlun Hong Juan T. López Navarrete

Abstract The recently synthesized regio‐regular poly(3‐hexylthiophene‐2,5‐diyl) selectively deuterated on the main chain backbone and/or on the hexyl side chain have given the opportunity to record their infrared (IR) and Raman spectra, and to carry out a spectroscopic study supported by density functional theory calculations. The Effective Conjugation Coordinate associated with the collective C=C stretching mode, with Raman scattering and IR absorption near 1,450 cm −1 , is used as a probe of the electronic structure and the molecular conformation of the chain backbone. With the help of the data collected from the deuterated species, the vibrational assignment for the structurally relevant 1,600–1,300 cm −1 region has been clarified. The excitation‐dependent wavenumbers and intensities of the C=C stretching Raman modes are discussed. Raman spectra excited in‐resonance or off‐resonance show the existence of a multimodal distribution of effective conjugation lengths that are ascribed to a phase hairy‐A with a practically flat backbone chain, a phase hairy‐B where the conformation of the backbone is slightly distorted, and an amorphous phase. IR spectra provide additional information on the Effective Conjugation Coordinate.

Resonance Raman spectroscopy

10.1002/jrs.5301

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Citations (19)