- Towards the Molecular Design of Spin-Crossover Complexes of 2,6-Bis(pyrazol-3-yl)pyridines
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The molecular design of spin-crossover complexes relies on controlling the spin state of a transition metal ion by proper chemical modifications of the ligands. Herein, the first N,N’-disubstituted 2,6-bis(pyrazol-3-yl)pyridines (3-bpp) are reported that, against the common wisdom, induce a spin-crossover in otherwise high-spin iron(II) complexes by increasing the steric demand of a bulky substituent, an ortho-functionalized phenyl group. As N,N’-disubstituted 3-bpp complexes have no pendant NH groups that make their spin state extremely sensitive to the environment, the proposed ligand design, which may be applicable to isomeric 1-bpp or other families of popular bi-, tri- and higher denticity ligands, opens the way for their molecular design as spin-crossover compounds for future breakthrough applications.
- Nikovskiy, Igor,Polezhaev, Alexander,Novikov, Valentin,Aleshin, Dmitry,Pavlov, Alexander,Saffiulina, Elnara,Aysin, Rinat,Dorovatovskii, Pavel,Nodaraki, Lydia,Tuna, Floriana,Nelyubina, Yulia
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- Synthesis and Spin State of the Iron(II) Complex with the N,N'-Disubstituted 2,6-Bis(pyrazol-3-yl)pyridine Ligand
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Abstract: The reaction of a new tridentate ligand 2,6-bis(5-tert-butyl-1-(2,6-difluorophenyl)-1H-pyrazol-3-yl)pyridine (L) with the divalent iron salt affords the iron(II) complex [Fe(L)2](BF4)2 (I), which is isolated in the individual state and characterized by elemental analysis, NMR spectroscopy, and X-ray diffraction analysis. According to the X-ray diffraction results and data of the Evans method, which makes it possible to determine the spin state of paramagnetic compounds in a solution from the NMR spectra, the iron(II) ion in complex I exists in the high-spin state (S = 2 for Fe(II)) and undergoes no temperature-induced spin transition in a range of 120–345 K.
- Aleshin, D. Yu.,Mel’nikova, E. K.,Nelyubina, Yu. V.,Nikovskii, I. A.,Polezhaev, A. V.
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- Synthesis, insecticidal activities, and structure-activity relationship of phenylpyrazole derivatives containing a fluoro-substituted benzene moiety
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Fluorinated organic compounds represent a growing and important family of commercial chemicals. Introduction of fluorine into active ingredients has become an effective way to develop modern crop protection products. Given the particular properties of fluorine and high efficiency and selectivity of diamide insecticides, we designed and synthesized 27 anthranilic diamides analogues containing fluoro-sustituted phenylpyrazole. A preliminary bioassay indicated that most target compounds exhibited good biological activity against Mythimna separata and Plutella xylostella. Compound IIIf containing a 2,4,6-trifluoro-substituted benzene ring showed 43% insecticidal activity against M. separata at 0.1 mg L-1, while the control chlorantraniliprole was 36%. The activity of IIIe against P. xylostella at 10-5 mg L-1 was 94%, compared with that of the control being 70%. Thus, introduction of fluorine into diamide insecticides was useful for increasing activity. Insect electrophysiology studies showed that the calcium concentration in the nerve cells of third M. separata larvae was elevated by IIIf, which further confirmed that ryanodine receptor (RyR) was its potential target.
- Gao, Li,Li, Huangong,Li, Yuxin,Li, Zhengming,Ma, Yi,Meng, Fanfei,Sun, Binqiao,Sun, Pengwei,Xie, Yongtao,Xiong, Lixia,Yang, Na,Zhang, Yan,Zhao, Yangyang,Zhou, Sha
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p. 11282 - 11289
(2020/11/09)
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