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21.
Matrab T Chehimi MM Perruchot C Adenier A Guillez A Save M Charleux B Cabet-Deliry E Pinson J 《Langmuir : the ACS journal of surfaces and colloids》2005,21(10):4686-4694
This paper reports on the preparation of poly(methyl methacrylate) (PMMA), poly(n-butyl acrylate) (PBA), and polystyrene (PS) brushes at the surface of conducting materials that were modified by the electrochemical reduction of a brominated aryl diazonium salt BF4-, +N2-C6H4-CH(CH3)-Br (D1). The grafted organic species -C6H4-CH(CH3)-Br was found to be very effective in initiating atom transfer radical polymerization (ATRP) of vinyl monomers. This novel approach combining diazonium salts and ATRP allowed PMMA, PBA, and PS brushes to be grown from the surface of iron electrodes. The polymer films were characterized in terms of their chemical structure by infrared reflection absorption spectroscopy and X-ray photoelectron spectroscopy. Atomic force microscopy studies indicated that the polymer brushes are densely packed. Contact angle measurements of water drops on PS and PMMA brushes were 88.1 +/- 2.0 and 70.3 +/- 2.1 degrees, respectively, which is consistent with the published wettability data for the corresponding polymer sheets. 相似文献
22.
Dr. Siddhartha De Dr. Alexandrine Flambard Buqin Xu Lise-Marie Chamoreau Geoffrey Gontard Dr. Laurent Lisnard Dr. Yanling Li Dr. Marie-Laure Boillot Prof. Rodrigue Lescouëzec 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(50):e202200783
The cyanidocobaltate of formula fac-PPh4[CoIII(Me2Tp)(CN)3] ⋅ CH3CN ( 1 ) has been used as a metalloligand to prepare polynuclear magnetic complexes (Me2Tp=hydrotris(3,5-dimethylpyrazol-1-yl)borate). The association of 1 with in situ prepared [FeII(bik)2(MeCN)2](OTf)2 (bik=bis(1-methylimidazol-2-yl)ketone) leads to a molecular square of formula {[CoIII{(Me2Tp)}(CN)3]2[FeII(bik)2]2}(OTf)2 ⋅ 4MeCN ⋅ 2H2O ( 2 ), whereas the self-assembly of 1 with preformed cluster [CoII2(OH2)(piv)4(Hpiv)4] in MeCN leads to the two-dimensional network of formula {[CoII2(piv)3]2[CoIII(Me2Tp)(CN)3]2 ⋅ 2CH3CN}∞ ( 3 ). These compounds were structurally characterized via single crystal X-ray analysis and their spectroscopic (FTIR, UV-Vis and 59Co NMR) properties and magnetic behaviours were also investigated. Bulk magnetic susceptibility measurements reveal that 1 is diamagnetic and 3 is paramagnetic throughout the explored temperature range, whereas 2 exhibits sharp spin transition centered at ca. 292 K. Compound 2 also exhibits photomagnetic effects at low temperature, selective light irradiations allowing to promote reversibly and repeatedly low-spin⇔high-spin conversion. Besides, the diamagnetic nature of the Co(III) building block allows us studying these compounds by means of 59Co NMR spectroscopy. Herein, a 59Co chemical shift has been used as a magnetic probe to corroborate experimental magnetic data obtained from bulk magnetic susceptibility measurements. An influence of the magnetic state of the neighbouring atoms is observed on the 59Co NMR signals. Moreover, for the very first time, 59Co NMR technique has been successfully introduced to investigate molecular materials with distinct magnetic properties. 相似文献
23.
Algraveain Igau Alexandrine Maraval Jean-Pierre Majoral 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1)
Abstract lmines are important classes of compounds in chemistry. In our continued investigation in the studies of the interactions betwcen group 4 (Zr, Ti) elements and main group elements we recently developped a new methodology for the preparation of various σ3, λ3 phospha-imines. Extension of this work allowed us to prepare unprecedented 8-π electron 6-membered phosphorus heterocycles; 1, 4 σ3, λ3 diphospha-2,6-diazines. The formation of these diazines involved for the first time the use of phosphorus derivatives as cyclization promoted reagents in zirconocene chemistry. 相似文献