Exploring structure based charge transport relationships in phenyl diketopyrrolopyrrole single crystals using a 2D π–π dimer model system

This document is the Accepted Manuscript version of the following article: Jesus Calvo-Castro, and Callum J. McHugh, ‘Exploring structure based charge transport relationships in phenyl diketopyrrolopyrrole single crystals using a 2D π–π dimer model system’, Journal of Materials Chemistry C, Issue 16, 2017, first published 28 March 2017. The version of record is available online at DOI: http://dx.doi.org/10.1039/C7TC00434F © Royal Society of Chemistry 2017Crystalline phenyl diketopyrrolopyrroles are often overlooked as charge transfer mediating materials in optoelectronic applications. We report an experimentally ratified two dimensional π–π model dimer system dispelling previous misconceptions regarding the potential of these materials as organic semiconductors and that will enable researchers to screen and predict charge transport potential solely on the basis of their single crystal derived π-stacking architectures. In testing our model system versus the available database of phenyl diketopyrrolopyrrole single crystal structures we reveal that these materials are characterised by intrinsically large thermal integrities and in many cases large charge transfer integrals, not solely restricted to dimeric interactions exhibiting close intermonomer arrangements and bearing low torsion of the core phenyl rings. This study will be of significant interest to the increasingly large community engaged in the quest to engineer π-conjugated organic based semiconducting devices and particularly those employing crystalline diketopyrrolopyrroles.Peer reviewe

Twist and shout: a surprising synergy between aryl and N-substituents defines the computed charge transport properties in a series of crystalline diketopyrrolopyrroles

This is the Accepted Manuscript version of an article accepted for publication in CyrstEngComm. Under embargo. Embargo end date: 22 November 2017. Jesus Calvo-Castrp, Sebastian Macza, Connor Thomson, Graeme Morris, Alan R. Kennedy and Callum J. McHugh, ‘Twist and shout: a surprising synergy between aryl and N-substituents defines the computed charge transport properties in a series of crystalline diketopyrrolopyrroles’, CrysEngComm, Vol 18(48): 9382-9390, first published online 22 November 2016, available at doi: 10.1039/C6CE02261HThe influence of systematic variation of aryl and N-substitution on predicted charge transport behaviour in a series of crystalline diketopyrrolopyrroles is evaluated. A correct combination of substituents is revealed to maximise those properties which dictate device performance in organic single crystals based upon this structural motif. For electron transport, furan and N-alkyl substitution emerge as optimal molecular design strategies, whilst phenyl structures bearing N-benzyl substituents are shown to offer the most significant promise as highly sought after crystalline hole transport materials.Peer reviewedFinal Accepted Versio

Luxación aislada del piramidal

ResumenAunque las luxaciones carpianas son lesiones relativamente frecuentes, la luxación aislada del piramidal es excepcional. Presentamos un caso aislado de luxación volar del hueso piramidal, revisando los casos similares publicados en la literatura y analizando los aspectos más importantes en relación con su diagnóstico y tratamiento.Varón de 38 años de edad, con caída sobre su mano derecha en hiperextensión. Inicialmente el diagnóstico pasó desapercibido. Al mes se realizó reducción abierta y estabilización con agujas de Kirchner.A los 4 años de la cirugía el paciente se encuentra asintomático y con la misma fuerza de agarre que la mano contralateral. Las radiografías postoperatorias muestran una buena reducción del carpo sin signos de inestabilidad.La falta de un diagnóstico inicial y en consecuencia un retraso en el tratamiento hacen más difícil el manejo de las lesiones, pero es una reducción inadecuada del carpo el factor pronóstico más negativo.AbstractAlthough carpal dislocations are a relatively common injury, isolated dislocation of the triquetrum is exceptional. The report of a new case is presented of isolated volar dislocation of the triquetrum, as well as an analysis of similar cases published in the literature. The main factors related to their diagnosis and treatment are also reviewed.A 38-year-old man fell and landed on his right hand in hyper-extension. Diagnosis was initially unnoticed. An open reduction and Kirchner wires stabilisation was performed one month later.Four years after surgery the patient was asymptomatic and with the same grip strength as contralateral hand. Post-operative X-rays were favourable with good carpal reduction and alignment and without carpal instability signs.The lack of an initial diagnosis and consequently a delayed treatment, make more difficult the injury management more difficult, but an inadequate carpal reduction the most negative prognostic factor

Impact of substituent effects on the Raman spectra of structurally related N-substituted diketopyrrolopyrroles

This document is the Accepted Manuscript version of the following article: Jesus Calvo-Castro, et al, ‘Impact of substituent effects on the Raman spectra of structurally related N-substituted diketopyrrolopyrroles’, Vibrational Spectroscopy, Vol. 83, pp. 8-16, March 2016, doi: https://doi.org/10.1016/j.vibspec.2015.12.004. This manuscript version is made available under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives License (http://creativecommons.org/licenses/by-nc-nd/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited, and is not altered, transformed, or built upon in any way.Control over vibrational frequency modes is important in optimising the performance and behaviour of conjugated organic materials employed as charge transfer mediators and optical components in optoelectronic devices. Raman spectroscopy represents a powerful technique that can be employed to determine the structural implications of molecular substitution on photophysical properties in such conjugated organic environments. Herein, we report for the first time, the optimised geometries for a series of eight systematically varied N-substituted diketopyrrolopyrroles as well as their experimental and computed Raman spectra, with special emphasis placed upon their spectral band assignments. Clear out-of-plane structural re-arrangements, including pyramidalisation of the lactam nitrogens arising from intramolecular H-bonding interactions were observed upon N-substitution in the reported systems, leading to significant vibrational frequency shifts for ν(Nsingle bondC) and ν(Cdouble bond; length as m-dashO) modes. In addition, mode scaling factors were determined and found to be comparable with those reported previously, employed using the same density functional. The following study addresses the implications of structural variation on the progression of those intense Raman modes which play a key role in tuning the photophysical properties of N-substituted diketopyrrolopyrrole systems and as such should be of broad interest to those developing functional materials based upon this molecular motifPeer reviewe

Fluorine Directed Two-Dimensional Cruciform π−π Stacking in Diketopyrrolopyrroles

This is the Accepted Manuscript Version of the following article: Jesus Calvo-Castro, Graeme Morris, Alan R. Kennedy, and Callum J. McHugh, “Fluorine Directed Two-Dimensional Cruciform π–π Stacking in Diketopyrrolopyrroles”, Crystal Growth and Design, Vol. 16 (9): 5385–5393, July 2016. Copyright © 2016 American Chemical Society.Enhanced bulk dimensionality in organic materials employed in optoelectronic devices is desirable and can overcome fabrication issues related to structural defects and grain boundaries. Herein, we report a novel fluorinated diketopyrrolopyrrole single crystal structure, which displays a unique, mutually orthogonal, 2-dimensional cruciform π−π stacking arrangement. The crystal structure is characterized by an unusually large number of nearest neighbor dimer pairs which contribute to a greater thermal integrity than structurally analogous equivalents. Binding energies and charge transfer integrals were computed for all of the crystal extracted dimer pairs by means of the M06-2X density functional at the 6- 311G(d) level. Although weak, a number of intermolecular interactions involving organic fluorine (C−F---H, πF---π, and C−F---πF) were identified to influence the supramolecular assembly of these dimer pairs. Charge transfer integrals for the two π−π stacking crystal dimers were determined using the energy splitting in dimer method. Ambipolar charge transport favoring electron transfer approaching that of rubrene is predicted in both of these π−π stacks, with a greater magnitude of coupling observed from those dimers perpetuating along the crystallographic a-axis. Charge transport behavior in the single crystal is greatly influenced by selective fluorination of the N-benzyl substituents and is consistent with the crystal extracted π−π stacking dimer geometries and their overall influence on wave function overlap. The reported structure is an interesting electron transport material that could be exploited, particularly in thin film based optoelectronic devices, where high bulk dimensionality is required.Peer reviewedFinal Accepted Versio

Effects of fluorine substitution on the intermolecular interactions, energetics and packing behaviour of N-benzyl substituted diketopyrrolopyrroles

This document is the Accepted Manuscript version of a Published Work that appeared in final form in Crystal Growth and Design, after peer review and technical editing by the publisher. To access the final edited and published work see doi: 10.1021/acs.cgd.6b00157.Rationalizing the effects of molecular substitution in π-conjugated organic materials arising from well-defined intermolecular interactions, which can influence the formation of predefined packing motifs and control the emergence of π–π stacking represents a current challenge in supramolecular design. Significant effort is potentially required to manage the impact on solid state packing behavior in materials that have been molecularly tuned to carry out specific photophysical and electrochemical functions. In this regard, fluorine substitution in π-conjugated systems has seen a recent surge of interest, primarily aimed toward the development of materials with enhanced optical and optoelectronic behavior. In light of this interest, in the following study, we report the synthesis and single crystal structures from a series of four novel and structurally related, symmetric, fluorinated N-benzyl substituted diketopyrrolopyrroles (DPPs). Two of the investigated series exhibit slipped cofacial π–π dimer pairs, which are consistent with those reported by us previously in halogenated DPPs. Significantly, this characteristic stacking motif of N-benzyl substituted DPPs can be carefully modified via the replacement of hydrogen atoms with trifluoromethyl and isosteric fluorine–hydrogen substituents. In the case of trifluoromethyl substitution, we identify a previously unobserved packing motif exhibiting a framework of well-defined channels propagating along the length of the crystallographic c-axis. In each of the reported systems, all of the nearest neighbor dimer pairs have been identified and their intermolecular interaction energies computed by means of the M06-2X density functional at the 6-311G(d) level. Through a detailed theoretical analysis involving the determination of cropped dimer energetics, organic fluorine is shown to play an active role in the stabilization of the crystal extracted dimer pairs through a number of additive and weak C–F---H, C–F---πF, and C–F---π intermolecular contacts. Contrary to recent reports, we demonstrate that substitution of hydrogen by fluorine can also lead to dramatic changes in solid state packing behavior as a consequence of these weak interactions. Given the importance of organic fluorine substitution in the construction of π-conjugated materials for optoelectronic materials, we feel that this work should be of interest to the wider community involved in supramolecular design of organic conjugated systems, and in particular to those investigating organic fluorine as well as diketopyrrolopyrrole containing architecturesPeer reviewedFinal Accepted Versio

Impact of systematic structural variation on the energetics of π−π stacking interactions and associated computed charge transfer integrals of crystalline diketopyrrolopyrroles

This document is the Accepted Manuscript version of a Published Work that appeared in final form in Crystal Growth & Design, copyright © 2014 American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see DOI: https://doi.org/10.1021/cg5010165, or ACS Articles on Request http://pubs.acs.org/page/policy/articlesonrequest/index.html/Control over solid state structure is critical for effective performance in optoelectronic devices bearing π-conjugated charge mediating organic materials. A series of five structurally related N-benzyl-substituted diketopyrrolopyrroles (DPPs) differing ... Novel crystal structures demonstrating long molecular axis, slipped, π−π cofacial stacking motifs and associated semiconductor bands in a series of N-benzylated diketopyrrolopyrroles are reported. Through variation of just 2 atoms from 60, clear crystal structure/(computed) charge transport activity interdependency is observed, with two structures exhibiting hole transport integrals comparable to Rubrene, a highly effective positive charge carrying, organic, crystalline materialPeer reviewedFinal Accepted Versio

Intermolecular interactions and energetics in the crystalline π–π stacks and associated model dimer systems of asymmetric halogenated diketopyrrolopyrroles

This document is the Accepted Manuscript version of a Published Work that appeared in final form in Crystal Growth & Design, © 2016 American Chemical Society, after peer review and technical editing by the publisher. To access the final edited and published work see DOI: 10.1021/acs.cgd.5b01656/Four novel structurally analogous asymmetric, halogenated N-benzyl substituted diketopyrrolopyrroles (DPP) have been synthesized, and their crystal structures obtained. All four crystal structures exhibit π–π stacks with very small displacements along their short molecular axes, which based upon our previous studies involving symmetrical DPPs is a characteristic of N-benzyl substitution. Intermolecular interaction energies were computed for extracted crystal π–π dimer pairs by means of M06-2X density functional at the 6-311G(d) level to investigate the most energetically favored position of the halogen atoms in FBDPP and ClBDPP structures. In addition, effective stabilization energies arising from both benzyl and halogen substitution in these derivatives and in BrBDPP and IBDPP π–π dimer pairs were determined in order to probe the impact of these groups on the resulting dimer stability. Effects of the intermonomer displacements along the long molecular axis, which have been shown by us previously to significantly influence wavefunction overlap and effective electronic coupling, were investigated in detail using aligned and anti-aligned model systems of ClDPP and BrDPP. The predictions of these model systems are remarkably consistent with the observed displacements in their crystal derived π–π dimer pair equivalents, offering insight into the effective role of intermolecular contacts in crystal structures involving this molecular motif, particularly with a view toward crystal engineering in these systems. As a result, we believe that this study should be of significant interest to the growing DPP based materials community and in general to those investigating the detailed manner by which substituents can be employed in the supramolecular design of crystalline molecular architectures.Peer reviewedFinal Accepted Versio

The wideband backend at the MDSCC in Robledo. A new facility for radio astronomy at Q- and K- bands

The antennas of NASA's Madrid Deep Space Communications Complex (MDSCC) in Robledo de Chavela are available as single-dish radio astronomical facilities during a significant percentage of their operational time. Current instrumentation includes two antennas of 70 and 34 m in diameter, equipped with dual-polarization receivers in K (18 - 26 GHz) and Q (38 - 50 GHz) bands, respectively. We have developed and built a new wideband backend for the Robledo antennas, with the objectives (1) to optimize the available time and enhance the efficiency of radio astronomy in MDSCC; and (2) to tackle new scientific cases impossible to that were investigated with the old, narrow-band autocorrelator. The backend consists of an IF processor, a FFT spectrometer (FFTS), and the software that interfaces and manages the events among the observing program, antenna control, the IF processor, the FFTS operation, and data recording. The whole system was end-to-end assembled in August 2011, at the start of commissioning activities, and the results are reported in this paper. Frequency tunings and line intensities are stable over hours, even when using different synthesizers and IF channels; no aliasing effects have been measured, and the rejection of the image sideband was characterized. The first setup provides 1.5 GHz of instantaneous bandwidth in a single polarization, using 8192 channels and a frequency resolution of 212 kHz; upgrades under way include a second FFTS card, and two high-resolution cores providing 100 MHz and 500 MHz of bandwidth, and 16384 channels. These upgrades will permit simultaneous observations of the two polarizations with instantaneous bandwidths from 100 MHz to 3 GHz, and spectral resolutions from 7 to 212 kHz.Comment: 9 pages, 8 figures. Accepted to Astronomy and Astrophysic

Verbal Memory and IQ Predict Adaptive Behavior in Children and Adolescents with High-Functioning Autism Spectrum Disorders

Adaptive deficits are commonly found in high functioning autism spectrum disorders (HF-ASD) despite of cognitive potential. Most studies have focused on the relationships between adaptive behavior and intellectual quotient (IQ) and have used correlations to study relationships between them. Few studies have analyzed cognitive variables other than IQ as potential predictors of adaptive behavior in HF-ASD using regression methods. This study aimed to analyze the impact of several cognitive variables on adaptive behavior in a sample of children and adolescents with HF-ASD. METHODS: Sample included 16 child and adolescent boys with HF-ASD (age between 7-17 years). Cognitive assessment included measures of general intelligence, visual memory, verbal memory, working memory and problem solving/flexibility tests. Vineland Adaptive Behavior Scales (VABS) was used to evaluate adaptive behavior. To establish the predictive capacity of the cognitive variables for adaptive functioning, linear regression models were fitted for each adaptive domain using a stepwise method. RESULTS: Verbal memory and IQ emerged as the main independent predictors for VABS adaptive scores. The 41% of the variance in Communication was predicted by IQ. The 35% of the variance in Daily Living Skills was predicted by verbal memory. Almost half of the variance in Socialization was predicted by both, verbal memory and IQ (49%). No other cognitive functions were associated with adaptive scores. CONCLUSIONS: The results highlight the strong impact of IQ and verbal memory on adaptive behavior in HF-ASD patients. These findings could contribute to identify potential targets of intervention