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On-surface synthesis of covalent coordination polymers on micrometer scale

Nano Research 2017年第3期10卷 933-940页

作者： mathieu Koudia Elena Nardi Olivier Siri mathieu abel Aix Marseille UniversitY CNRS IM2NP UMR 7334 13397 Marseille France Aix Marseille UniversitY CNRS CINaM UMR 7325 13288 Marseille France

On-surface synthesis under ultrahigh vacuum provides a promising strategy to control matter at the atomic level, with important implications for the design of new two-dimensional materials having remarkable electronic, magnetic, or catalytic properties. This strategy must address the problem of limited extension of the domains due to the irreversible nature of covalent bonds, which prevents the ripening of defects. We show here that extended materials can be produced by a controlled co-deposition process. In particular, co-deposition of quinoid zwitterion molecules with iron atoms on a Ag（111） surface held at 570 K allows the formation of micrometer-sized domains based on covalent coordination bonds. This work opens up the construction of micrometer-scale single-layer covalent coordination materials under vacuum conditions.

关键词： on-surface synthesis scanning tunnelingmicroscopy (STM) two-dimensional polymer covalent organic frameworks

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Steric and electronic selectivity in the synthesis of Fe- 1,2,4,5-tetracyanobenzene （TCNB） complexes on Au（111）： From topological confinement to bond formation

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Nano Research 2014年第6期7卷 888-897页

作者： Shawulienu Kezilebieke Anis Amokrane Mauro Boero Sylvain Clai mathieu abel Jean-Pierre Bucher Institut de Physique et Chimie des Materiaux de Strasbourg CNRS UMR 7504 Universit~ de Strasbourg F-67034 Strasbourg France Universite Aix-Marseille IM2NP CNRS UMR 7334 Campus de Saint-Jereme Case 142 F- 13397 Marseille Cedex 20 France

A study of the surface assisted self-assembly of 1,2,4,5-tetracyanobenzene (TCNB) acceptor molecules and Fe atoms on an Au(111) surface is presented. While conditions to get the two-dimensional arrays of stable Fe(TCNB)4 complexes are clearly identified, ultrahigh vacuum scanning tunneling microscopy and spectroscopy (STM/STS) coupled with first-principles calculations reveals that situations may occur where Fe and TCNB survive on the surface (as Fe-4TCNB entities) at a higher density than the original molecular monolayer without forming coordination bonds with each other. It is found that the square planar coordination of the Fe(TCNB)4 monomer complexes cannot fully develop in the presence of lateral strain due to growth-induced confinement. A phenomenon similar to steric hindrance involving a strongly modified chirality with a Fe-N-C bond angle of 120° compared to the 180° for the stable complex may then explain why the Fe atom keeps its metallic bond with the surface. The competition between steric and electronic effects, not reported before, may arise elsewhere in surface chemistry involved in the synthesis of new and potentially useful organic nanomaterials.

关键词：空间位阻电子效应铁原子拓扑约束粘合合成 Au 氰基

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Epidemiological, Radio-Clinical and Histological Correlations of Breast Lesions ACR 3, ACR 4 and ACR 5 in the Ouagadougou’ City

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Open Journal of Radiology 2020年第3期10卷 184-192页

作者： Massara Koné-Sigué Aïscha Madina Napon Soré Moussa Zanga Glwadys Cherlyn Béréhoudougou Kaboré mathieu Kafando Pakisba Ali Ouédraogo abel Yomboué Bamouni Léonie Claudine Lougué-Sorgho Department of Radiology Pediatric University Hospital Center (CHUP) Charles De gaulles Ouagadougou Burkina Faso Department of Radiology University Hospital Center (CHU) Yalgado Ouédraogo Ouagadougou Burkina Faso

Objective: To correlate the epidemiological and histological data of breast le-sions ACR 3, ACR 4 and ACR 5 biopsied on ultrasound in the city of Ouaga-dougou. Materials and methods: This was a retrospective study of data for 02 years (2015-2017) in the city of Ouagadougou. With the approval of the Ethics Committee for Health Research, the study focused on the histological results and radiological reports of biopsied lesions. Results: A total of 150 patients files had been collected. Breast lesions classified as ACR 4 were 50%, ACR 3 40% and ACR 5 10%. The risk factors were related to the ACR class. Ultra-sound was performed in all patients. The masses were the most common ele-mentary lesions found in breast imaging. On histology 98 lesions were benign, 16 intermediate lesions and 36 malignant lesions. Fibroids were the most common benign lesions of the ACR 3 and ACR 4 classes. Invasive ductal car-cinoma was the most common histologic type among malignant lesions in all ACR classes. Conclusion: Cancerous lesions are discovered late in our context. The ACR classification must always take into account discriminative ele-ments.

关键词： Breast Cancer ACR Echo-Mammography Burkina Faso

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