- Substituent Effects on Exchange Coupling and Magnetic Relaxation in 2,2′-Bipyrimidine Radical-Bridged Dilanthanide Complexes
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Systematic analysis of related compounds is crucial to the design of single-molecule magnets with improved properties, yet such studies on multinuclear lanthanide complexes with strong magnetic coupling remain rare. Herein, we present the synthesis and magnetic characterization of the series of radical-bridged dilanthanide complex salts [(Cp*2Ln)2(μ-5,5′-R2bpym)](BPh4) (Ln = Gd, Dy; R = NMe2 (1), OEt (2), Me (3), F (4); bpym = 2,2′-bipyrimidine). Modification of the substituent on the bridging 5,5′-R2bpym radical anion allows the magnetic exchange coupling constant, JGd-rad, for the gadolinium compounds in this series to be tuned over a range from -2.7 cm-1 (1) to -11.1 cm-1 (4), with electron-withdrawing or -donating substituents increasing or decreasing the strength of exchange coupling, respectively. Modulation of the exchange coupling interaction has a significant impact on the magnetic relaxation dynamics of the single-molecule magnets 1-Dy through 4-Dy, where stronger JGd-rad for the corresponding Gd3+ compounds is associated with larger thermal barriers to magnetic relaxation (Ueff), open magnetic hysteresis at higher temperatures, and slower magnetic relaxation rates for through-barrier processes. Further, we derive an empirical linear correlation between the experimental Ueff values for 1-Dy through 4-Dy and the magnitude of JGd-rad for the corresponding gadolinium derivatives that provides insight into the electronic structure of these complexes. This simple model applies to other organic radical-bridged dysprosium complexes in the literature, and it establishes clear design criteria for increasing magnetic operating temperatures in radical-bridged molecules.
- Gould, Colin A.,Mu, Edward,Vieru, Veacheslav,Darago, Lucy E.,Chakarawet, Khetpakorn,Gonzalez, Miguel I.,Demir, Selvan,Long, Jeffrey R.
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p. 21197 - 21209
(2020/12/22)
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- NOVEL 1-(BIPHENYL-4-YL-METHYL)-1H-IMIDAZOLE DERIVATIVE AND PHARMACEUTICAL PRODUCT CONTAINING SAME
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Disclosed is a novel 1-(biphenyl-4-yl-methyl)-1H-imidazole derivative represented by general formula (I), which has both angiotensin II receptor antagonist activity and PPAR-γ activating activity and is useful as a prophylactic and/or therapeutic agent fo
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Page/Page column 14
(2012/10/23)
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- NOVEL PYRROLOY2,3-d¨PYRIMIDINE COMPOUND
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Disclosed is a novel pyrrolo[2,3-d]pyrimidine compound represented by formula [I] or a pharmacologically acceptable salt thereof, which has a GPR119 receptor agonistic activity and is useful for a pharmaceutical. In formula [I], E represents a group repre
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Page/Page column 62
(2011/12/12)
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- TYROSINE KINASE INHIBITORS
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The present invention relates to pyridazin-4(1H)-one derivatives, that are useful for treating cellular proliferative diseases, for treating disorders associated with MET activity, and for inhibiting the receptor tyrosine kinase MET. The invention also related to compositions which comprise these compounds, and methods of using them to treat cancer in mammals.
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Page/Page column 154
(2011/08/03)
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