- Spin-transition behaviour in chains of FeII bridged by 4-substituted 1,2,4-triazoles carrying alkyl tails
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A family of polymeric 1-dimensional chains of iron(II) species showing the spin-crossover phenomenon has been synthesized using 4-n-alkyl-1,2,4-triazoles as bridging ligands. The influence of the length of the alkyl tails on the triazole ligands on characteristic features of the spin transition was studied, showing degrading of steepness with increasing length. A set of four counter ions has been used to access a wider range of transition temperatures. Large hysteresis loops are detected with small tails, mainly for the methyl and ethyl substituted products. In most cases longer tails weaken co-operativity and hysteresis gradually decreases to zero. However it is shown that with certain anions hysteresis remains, even with very long tails on the triazoles. Weakening of the co-operativity mainly arises from a diminution of the length of the polymeric chains with increasing alkyl tails on the triazole. This effect is anion dependent. A strong interaction along the polymeric chains is confirmed.
- Roubeau,Alcazar Gomez,Balskus,Kolnaar,Haasnoot,Reedijk
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- Azacyclo-dicarbene subunit borane ionic liquid and preparation method thereof
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The invention relates to an azacyclo-dicarbene subunit borane ionic liquid and a preparation method thereof. The azacyclo-dicarbene subunit borane ionic liquid has a structural formula I as shown in the specification. A method for preparing the compound of formula I comprises the following main steps: performing an alkylation reaction on 1,2,4-triazole and a carbonic ester compound, further performing a quaternary amination reaction with halogenated hydrocarbon, and finally performing a reaction with sodium borohydride, thereby obtaining a target product. The ionic liquid provided by the invention can be used as a self-combustion type green rocket propellant, and has the advantages of being short in ignition delay time, good in water stability, large in density ratio impact value, and thelike. In the formula I, R1 is selected from any one of alkyl, and R2 is selected from any one of hydrocarbyl substituent groups.
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Paragraph 0025; 0028
(2018/07/30)
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- Dipalladium complexes with triazolidin-diylidene bridges and their catalytic activities
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The 1,2,4-trimethyltriazolidin-3,5-diylidene (ditz) bridged dipalladium heterotetracarbene complex [PdBr2(iPr2-bimy)] 2(μ-ditz) (3) (iPr2-bimy = 1,3-diisopropylbenzimidazolin-2-ylidene) was prepared by Ag-carbene transfer involving the 1,2,4-trimethyltriazolium dication (C), Ag2O, and the precursor complex (iPr2-bimyH)[PdBr3( iPr2-bimy)] (2). Bromido substitution of 3 with AgO 2CCH3 and AgO2CCF3afforded the carboxylato complexes [Pd(O2CCH3)2( iPr2-bimy)]2(μ-ditz) (4) and [Pd(O 2CCF3)2(iPr2-bimy)] 2(μ-ditz) (5). Multinuclei NMR spectroscopies and X-ray diffraction analyses showed that the all-trans isomers of 3, 4, and 5 are the predominant products in all three cases. In addition, the decomposition product of complex 4, trans-[Pd(O2CCH3)2( iPr2-bimy)2] (trans-6) was structurally determined by X-ray crystallography. A comparative catalytic study revealed the superiority of complexes 3, 4, and 5 over the previously reported mononuclear bis(benzimidazolin-2-ylidine) complexes without ditz bridges in the Mizoroki-Heck coupling reaction. Overall, complex 4 bearing acetato coligands showed the best catalytic performance.
- Guo, Shuai,Huynh, Han Vinh
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experimental part
p. 4565 - 4573
(2012/07/27)
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- Radical deoxygenation of xanthates and related functional groups with new minimalist N-heterocyclic carbene boranes
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Minimalist N-heterocyclic carbene boranes 1,3-dimethylimidazol-2- ylideneborane and 2,4-dimethyl-1,2,4-triazol-3-ylideneborane are readily available and have low molecular weights. They exhibit superior performance to first-generation NHC-boranes, providi
- Ueng, Shau-Hua,Fensterbank, Louis,Lacote, Emmanuel,Malacria, Max,Curran, Dennis P.
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supporting information; experimental part
p. 3002 - 3005
(2010/08/20)
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- An investigation into the alkylation of 1,2,4-triazole
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The alkylation of 1,2,4-triazole with 4-nitrobenzyl halides and a variety of bases afforded the 1- and 4-alkylated isomers with a consistent regioselectivity of 90:10. Previously reported regiospecific alkylations of 1,2,4-triazole were re-examined and the quoted isomer ratios were shown to depend on the isolation procedure. The use of DBU as base in the alkylation of 1,2,4-triazole allows for a convenient and high yielding synthesis of 1- substituted-1,2,4-triazoles. (C) 2000 Elsevier Science Ltd.
- Bulger, Paul G.,Cottrell, Ian F.,Cowden, Cameron J.,Davies, Antony J.,Dolling, Ulf-H.
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p. 1297 - 1301
(2007/10/03)
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- 1,2,3-Benzothiadiazole derivatives
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Novel 1,2,3-benzothiadiazole derivatives of the formula STR1 in which Het has the meanings set forth in the specification, and addition products thereof with an acid or metal salt are very effective for the control of undesired microorganisms. Novel intermediates of the formulae STR2 in which Het1 and R5 have the meanings given in the specification.
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- Novel Type Elimination Reactions of Sulfoxides Bearing Several Heteroaromatics: Trapping of Sulfines with 2,3-Dimethyl-1,3-butadiene
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Previously we reported the novel thioaldehydes generation via thermolyses of phenacyl sulfoxides bearing some heteroaromatics. Thermolysis of sulfoxides (1a,b and 2a-4a) bearing other heterocycles such as thiadiazole, triazole, and tetrazole in the presence of 2,3-dimethyl-1,3-butadiene in dioxane at 100 °C led to the unexpected products 6-substituted-5,6-dihydro-3,4-dimethyl-2H-thiapyran 1-oxide (5a,b). These products were considered to be formed by the Diels-Alder reaction of the diene with the sulfines formed initially by the thermal decomposition of the sulfoxides. The rate acceleration and the improvement of the yield by addition of 1.5 equiv of triethylamine, especially in the case of ethoxycabonylmethyl sulfoxide 1c, was observed. The cis-trans selectivity for sulfine cycloadducts was also studied by NMR spectrometry. The reactions of α-substituted phenacyl sulfoxides 1d-f bearing a phenyl-substituted tetrazolyl group in the presence of the same diene were also studied.
- Morita, Hiroyuki,Takeda, Masahiro,Yoshimura, Toshiaki,Fujii, Takayoshi,Ono, Shin,Shimasaki, Choichiro
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p. 6730 - 6737
(2007/10/03)
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- Oxidative Alkylation of Azoles. III. Reaction of N-Chloro-1,2,4-triazole with Methyl Iodide
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Reaction of 1-chloro-1,2,4-triazole with methyl iodide in methylene chloride or chloroform at 20-40 deg C results in formation of products of mono- and dialkylation of the ring at positions 1 and 4.Under the same conditions, the 1,4-dimethyltriazolium salt gives rise to 5-iodo derivative.
- Kurenkov, A. A.,Pevzner, M. S.
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p. 1118 - 1121
(2007/10/03)
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- Alkylation, Acylation and Silylation of Azoles
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Performing alkylation, acylation and silylation reactions in separate deprotonation and nucleophilic displacement steps allows for better control of reaction conditions and facilitates problem handling in these processes.In the alkylation of azoles the alkylating agents and solvents possess individual reaction capabilities which seem to be approximately additive.Monoalkylation occurs if the sum of the normalized reaction potentials is equal or larger than the pKa value of the azole.Dialkylation is avoided by keeping the sum of the normalized reaction potentials below the pKa value of the alkylazole.The applicability of these principles is demonstrated by the development of effective procedures for the methylation, benzylation, acetylation, methoxycarbonylation and trimethylsilylation of azoles.
- Begtrup, Mikael,Larsen, Peter
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p. 1050 - 1057
(2007/10/02)
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- INTRODUCTION OF SUBSTITUENTS INTO 5-MEMBERED AZA-HETEROAROMATICS
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With emphasis on mono- and regio-selectively, methods for introduction of substituents at nitrogen and carbon atoms of 5-membered aza-heteroaromatics have been developed.The methods involve application of activation and of assistant groups for direction and protection.Activation has been achieved by the use of quaternary azolium ions and azol-N-oxides as reactive intermediates.If necessary, the N-oxides were further activated by alkylation or acylation.
- Begtrup, Mikael
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p. 573 - 598
(2007/10/02)
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