Incarcerated vermiform appendix in a left-sided inguinal hernia

We report here of a patient with an incarcerated vermiform appendix occurring in a left-sided indirect inguinal hernia. Occasionally, appendices are found in a hernial sac; however, the finding of an incarcerated vermiform appendix in an inguinal hernia on the left side is very unusual and has only been previously described once. The patient suffering this rare entity underwent appendectomy and repair of the hernia and experienced an uneventful postoperative recovery. The possibility of the presence of a situs inversus, or malrotation, as an underlying cause for the observed pathology was excluded by x-ray examinatio

Synthesis beyond the redox-active tetrathiafulvalene (TTF) molecule: From a topological control in TTF based macrocycles, towards functional chemical systems

Date du colloque&nbsp;: 05/2009</p

Bulk and surface switching in Mn-Fe-based Prussian Blue Analogues

Many Prussian Blue Analogues are known to show a thermally induced phase transition close to room temperature and a reversible, photo-induced phase transition at low temperatures. This work reports on magnetic measurements, X-ray photoemission and Raman spectroscopy on a particular class of these molecular heterobimetallic systems, specifically on Rb0.81Mn[Fe(CN)6]0.95_1.24H2O, Rb0.97Mn[Fe(CN)6]0.98_1.03H2O and Rb0.70Cu0.22Mn0.78[Fe(CN)6]0.86_2.05H2O, to investigate these transition phenomena both in the bulk of the material and at the sample surface. Results indicate a high degree of charge transfer in the bulk, while a substantially reduced conversion is found at the sample surface, even in case of a near perfect (Rb:Mn:Fe=1:1:1) stoichiometry. Thus, the intrinsic incompleteness of the charge transfer transition in these materials is found to be primarily due to surface reconstruction. Substitution of a large fraction of charge transfer active Mn ions by charge transfer inactive Cu ions leads to a proportional conversion reduction with respect to the maximum conversion that is still stoichiometrically possible and shows the charge transfer capability of metal centers to be quite robust upon inclusion of a neighboring impurity. Additionally, a 532 nm photo-induced metastable state, reminiscent of the high temperature Fe(III)Mn(II) ground state, is found at temperatures 50-100 K. The efficiency of photo-excitation to the metastable state is found to be maximized around 90 K. The photo-induced state is observed to relax to the low temperature Fe(II)Mn(III) ground state at a temperature of approximately 123 K.Comment: 12 pages, 8 figure

Novel mechanism of photoinduced reversible phase transitions in molecule-based magnets

A novel microscopic mechanism of bi-directional structural changes is proposed for the photo-induced magnetic phase transition in Co-Fe Prussian blue analogues on the basis of ab initio quantum chemical cluster calculations. It is shown that the local potential energies of various spin states of Co are sensitive to the number of nearest neighbor Fe vacancies. As a result, the forward and backward structural changes are most readily initiated by excitation of different local regions by different photons. This mechanism suggests an effective strategy to realize photoinduced reversible phase transitions in a general system consisting of two local components.Comment: 4 pages, LaTex, 3 figures, to appear in Phys. Rev. Let

Numerical Study of a Mixed Ising Ferrimagnetic System

We present a study of a classical ferrimagnetic model on a square lattice in which the two interpenetrating square sublattices have spins one-half and one. This model is relevant for understanding bimetallic molecular ferrimagnets that are currently being synthesized by several experimental groups. We perform exact ground-state calculations for the model and employ Monte Carlo and numerical transfer-matrix techniques to obtain the finite-temperature phase diagram for both the transition and compensation temperatures. When only nearest-neighbor interactions are included, our nonperturbative results indicate no compensation point or tricritical point at finite temperature, which contradicts earlier results obtained with mean-field analysis.Comment: Figures can be obtained by request to [email protected] or [email protected]

Cooperative thermal and optical switching of spin states in a new two-dimensional coordination polymer

{Fe(pmd)2[Cu(CN)2]2} (pmd = pyrimidine) displays a rigid two-dimensional structure and undergoes thermal- and optical-driven spin crossover behaviour; cooperative elastic coupling between iron(II) ions in the framework induces thermal hysteresis in the HS↔LS conversion and sigmoidal HS→LS relaxation of the photo-induced HS state at low temperatures.Niel, Virginie, [email protected] ; Galet Domingo, Ana Guadalupe, [email protected] ; Gaspar Pedros, Ana Belen, [email protected] ; Real Cabezos, Jose Antonio, [email protected]

On-Surface Synthesis and Characterization of Triply Fused Porphyrin–Graphene Nanoribbon Hybrids

This is the peer reviewed version of the following article: Angewandte Chemie - International Edition 59. 3 (2020): 1334-1339, which has been published in final form at https://doi.org/10.1002/anie.201913024. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived VersionsOn-surface synthesis offers a versatile approach to prepare novel carbon-based nanostructures that cannot be obtained by conventional solution chemistry. Graphene nanoribbons (GNRs) have potential for a variety of applications. A key issue for their application in molecular electronics is in the fine-tuning of their electronic properties through structural modifications, such as heteroatom doping or the incorporation of non-benzenoid rings. In this context, the covalent fusion of GNRs and porphyrins (Pors) is a highly appealing strategy. Herein we present the selective on-surface synthesis of a Por–GNR hybrid, which consists of two Pors connected by a short GNR segment. The atomically precise structure of the Por–GNR hybrid has been characterized by bond-resolved scanning tunneling microscopy (STM) and noncontact atomic force microscopy (nc-AFM). The electronic properties have been investigated by scanning tunneling spectroscopy (STS), in combination with DFT calculations, which reveals a low electronic gap of 0.4 eVFinancial support from Spanish MICINN (CTQ2017‐85393‐P) is acknowledged. IMDEA Nanociencia acknowledges support from the “Severo Ochoa” Programme for Centres of Excellence in R&D (MINECO, Grant SEV2016‐0686). This work was supported by the Swiss National Science Foundation (200020_182015, IZLCZ2_170184) and the NCCR MARVEL funded by the Swiss National Science Foundation (51NF40‐182892). Computational support from the Swiss Supercomputing Center (CSCS) under project ID s904 is gratefully acknowledged. Q.S. acknowledges the EMPAPOSTDOCS‐II programme under the Marie Sklodowska‐Curie grant agreement No 75436

Self-Assembled Molecular-Electronic Films Controlled by Room Temperature Quantum Interference

If single-molecule, room-temperature, quantum interference (QI) effects could be translated into massively parallel arrays of molecules located between planar electrodes, QI-controlled molecular transistors would become available as building blocks for future electronic devices. Here, we demonstrate unequivocal signatures of room-temperature QI in vertical tunneling transistors, formed from self-assembled monolayers (SAMs), with stable room-temperature switching operations. As a result of constructive QI effects, the conductances of the junctions formed from anthanthrene-based molecules with two different connectivities differ by a factor of 34, which can further increase to 173 by controlling the molecule-electrode interface with different terminal groups. Field-effect control is achieved using an ionic liquid gate, whose strong vertical electric field penetrates through the graphene layer and tunes the energy levels of the SAMs. The resulting room-temperature on-off current ratio of the lowest-conductance SAMs can reach up to 306, about one order of magnitude higher than that of the highest-conductance SAMs