- Complex compounds based on 1-isopropenylimidazoles and -pyrazole
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With respect to Co2+, Ni2+, Zn2+,Cd 2+, Cu2+, Pd2+, and Sn4+ salts, 1-isopropenyl-substituted imidazole, 2-methylimidazole, and pyrazole behave as monodentate ligands with only one coordination center on the N1 and N2 atoms, respectively; 1-isopropenylpyrazole under complex-formation conditions is dealkylated to form pyrazole complexes. The reaction with HCl leaves the unsaturated substituent in 1-isopropenylimidazole intact and yields corresponding hydrochlorides by the N3 atom of the heterocycle. The least basic 1-isopropenylpyrazole takes up HCl also by the double bond of the alkenyl group.
- Zyryanova,Baikalova,Tarasova,Afonin,Kukhareva,Maksimova,Trofimov
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- Coordination chemistry in the solid state: Synthesis and interconversion of pyrazolium salts, pyrazole complexes, and pyrazolate MOFs
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Solid pyrazole reacts with HCl gas to form pyrazolium chloride [H 2pz]Cl, which reacts in the solid state, under grinding, with metal chlorides MCl2 (M = Co, Zn, Cu) to form the pyrazolium tetrachlorometallate salts [H2pz]2[MCl4] (M = Co 1, Zn 3, Cu 5). Salt 5 cannot be made in solution, and upon standing at room temperature spontaneously emits HCl to give the coordination compound [CuCl 2(Hpz)2] (6). Compounds 1 and 3 do not exhibit this behaviour, but can be ground together with bases such as KOH or K 2CO3 to effect the elimination of HCl and afford their respective [MCl2(Hpz)2] compounds (M = Co 2, Zn 4). 2, 4 and 6 can also be synthesised in the solid-state by direct reaction of the appropriate metal chloride with pyrazole, or by reaction of a basic metal salt such as the carbonate or hydroxide with pyrazolium chloride. 4 and 6 {and their nickel analogue [NiCl2(Hpz)2]} can be ground with a further two equivalents of base to make the known polymeric metal pyrazolates [M(pz)2]n (M = Ni 7, Cu 8, Zn 9); the same reaction appears to work for the cobalt analogue 2, but the presumed product [Co(pz) 2]n10 then decomposes by oxidation. The imidazolate complexes [M(im)2] (M = Ni, 11; Cu, 12; Zn, 13; Co, 14) were similarly prepared by grinding the appropriate [M(Him)2Cl 2] precursor with KOH. The Royal Society of Chemistry 2010.
- Adams, Christopher J.,Kurawa, Mukhtar A.,Orpen, A. Guy
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- Pyrazolium Phase-Change Materials for Solar-Thermal Energy Storage
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Thermal energy storage technology utilizing phase-change materials (PCMs) can be a promising solution for the intermittency of renewable energy sources. This work describes a novel family of PCMs based on the pyrazolium cation, that operate in the 100–200
- Matuszek, Karolina,Vijayaraghavan,Forsyth, Craig M.,Mahadevan, Surianarayanan,Kar, Mega,MacFarlane, Douglas R.
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- Anti-inflammator 1,n-diarylpyrazol-3-amines
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There are described compounds of formula I, STR1 in which either R2 represents hydrogen, alkyl or Ar2, and R3 represents hydrogen, alkyl or alkyl substituted by Ar3 ; or R2 and R3 together
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