16227-12-6Relevant articles and documents
BENZOXAZOLE DERIVATIVES AND FLUORESCENT MATERIAL COMPRISING THE SAME
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Paragraph 0204-0208, (2021/07/13)
A benzoxazole derivative represented by Structural Formula 1 is provided. Thus, the present invention is not limited thereto. A fluorescent material is provided to remarkably improve fluorescence yield, to have excellent dyeing property and dispersibility, to minimize environmental pollution and to improve economic feasibility. Structural 1.
Spin Crossover in Dinuclear N4S2 Iron(II) Thioether-Triazole Complexes: Access to [HS-HS], [HS-LS], and [LS-LS] States
Hogue, Ross W.,Feltham, Humphrey L. C.,Miller, Reece G.,Brooker, Sally
, p. 4152 - 4165 (2016/05/24)
Access to a new family of thioether-linked PSRT ligands, 4-substituted-3,5-bis{[(2-pyridylmethyl)sulfanyl]methyl}-4H-1,2,4-triazoles (analogues of the previously studied amino-linked PMRT ligands), has been established. Four such ligands have been prepared, PSPhT, PSiBuT, PSt-BuPhT, and PSMePhT, with R = Ph, iBu, t-BuPh, and MePh, respectively. Three dinuclear colorless to pale green iron(II) complexes, [FeII2(PSRT)2](BF4)4·solvent, featuring N4S2 donor sets, were prepared. Single-crystal structure determinations on [FeII2(PSPhT)2](BF4)4·2MeCN·H2O, [FeII2(PSPhT)2](BF4)4·21/2MeCN·1/2H2O·THF, [FeII2(PSMePhT)2](BF4)4·2MeCN, and [FeII2(PSiBuT)2](BF4)4·4MeCN reveal that all four are stabilized in the [HS-HS] state to 100 K and that both possible binding modes of the bis-terdentate ligands, cis- and trans-axial, are observed. Variable-temperature magnetic susceptibility studies of air-dried crystals (solvatomorphs of the single crystal samples) reveal the first examples of spin crossover (SCO) for a dinuclear iron(II) complex with N4S2 coordination. Specifically, [FeII2(PSPhT)2](BF4)4·21/2H2O undergoes a multistep but complete SCO from [HS-HS] to [LS-LS], whereas [FeII2(PSMePhT)2](BF4)4·11/2MeCN·2H2O exhibits a half-SCO from [HS-HS] to [HS-LS]. In contrast, [FeII2(PSiBuT)2](BF4)4·MeCN·H2O remains [HS-HS] down to 50 K. The reflectance spectrum of pale green [FeII2(PSPhT)2](BF4)4·1/2CHCl3·21/2H2O (solvatomorph A) reveals a trace of LS character (572 nm band 1A1g → 1T1g). Evans' 1H NMR method and UV-vis spectroscopy studies revealed that on cooling dark green acetonitrile solutions of these complexes from 313 to 233 K, all three undergo SCO centered at or near room temperature. The tendency of the complexes to go LS in solution reflects the electronic impact of R on the σ-donor strength of the PSRT ligand, whereas the opposite trend in stabilization of the LS state is seen in the solid state, where crystal packing effects, of the R group and solvent content, dominate the SCO behavior.
Syntheses, structural variation, and characterization of a series of crystalline coordination compounds with 4-benzene-1,2,4-triazole: Polymorph, incomplete spin transition, and single crystal-to-single crystal transformation
Wu, Xiang Xia,Wang, You You,Yang, Pan,Xu, Yao Yao,Huo, Jian Zhong,Ding, Bin,Wang, Ying,Wang, Xiuguang
, p. 477 - 490 (2014/03/21)
Based on the 4-substituted 1,2,4-triazole derivate ligand 4-benzene-1,2,4-triazole (L), a series of crystalline coordination complexes varying from mononuclear to trinuclear species, namely, [Zn(L) 2Br2] (1), [Zn(L)2Br2] (2), [Fe(L)4(NCS)2]2 (3), [Fe2(μ 2-L)3(L)2(NCS)4]·CH 3OH·CH3CH2OH (4), [Fe 2(μ2-L)3(L)2(NCS) 4]·2CH3CH2OH (5), [Fe 2(μ2-L)3(L)2(NCS) 4]·2CH3CH2OH·1.5H2O (6), and [Ni3(μ2-L)6(L)4(H 2O)2](NO3)6·15.5H 2O (7), have been isolated. 1 and 2 present a temperature-induced polymorphic phenomenon of two zinc(II) coordination complexes with L. The solvent effect plays the key role for the self-assembly of these Fe(II) complexes 3-6: 3 contains mononuclear Fe(L)4(NCS)2 units without spin-transition behavior, whereas both 4 and 5 present binuclear Fe(II) complexes with three N1,N2-1,2,4-triazole bridges exhibiting incomplete spin-transition behavior. The low-temperature X-ray structural analysis (100 K) of 4 also confirms that one of the Fe(II) centers is located at the low-spin (LS) state and the other Fe(II) center is located at the high-spin (HS) state. Interestingly, when the binuclear Fe(II) complex 5 was exposed in the water atmosphere, solvent-induced single crystal-to-single crystal transformation can be observed, and the binuclear Fe(II) complex 6 exhibiting antiferromagnetic interactions can be isolated. Further, a trinuclear crystalline compound is isolated when Ni(II) salts were used to react with L. Variable-temperature magnetic susceptibility measurement (2-300 K) reveals antiferromagnetic interactions in 7. The polymorphic phenomenon (1 and 2), incomplete spin-transition phenomenon (4 and 5), and single crystal-to-single crystal transformation (from 5 to 6) also reveal great potential in the construction of these novel functional materials with L.