VI. Darstellung und Derivate des freien Pyrazols

Buchner,; Fritsch, M.

doi:10.1002/jlac.18932730212

Cited by 19 publications

(2 citation statements)

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“…All reagents were of analytical grade, being used without further purification. 3,5dimethyl-4-nitro-pyrazole (dmnpz) was synthesized according to literature procedures [33][34][35]. The content in carbon, hydrogen and nitrogen was determined by elemental analysis using a Perkin Elmer PE 2400 analyzer (Perkin Elmer, Boston, MA, USA).…”

Section: Materials and Physical Measurementsmentioning

confidence: 99%

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New Syntheses, Analytic Spin Hamiltonians, Structural and Computational Characterization for a Series of Tri-, Hexa- and Hepta-Nuclear Copper (II) Complexes with Prototypic Patterns

Toader¹,

Buta²,

Cimpoesu³

et al. 2021

Chemistry

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We present a series of pyrazolato-bridged copper complexes with interesting structures that can be considered prototypic patterns for tri-, hexa- and hepta- nuclear systems. The trinuclear shows an almost regular triangle with a μ3-OH central group. The hexanuclear has identical monomer units, the Cu6 system forming a regular hexagon. The heptanuclear can be described as two trinuclear moieties sandwiching a central copper ion via carboxylate bridges. In the heptanuclear system, the pyrazolate bridges are consolidating the triangular faces, which are sketching an elongated trigonal antiprism. The magnetic properties of these systems, dominated by the strong antiferromagnetism along the pyrazolate bridges, were described transparently, outlining the energy levels formulas in terms of Heisenberg exchange parameters J, within the specific topologies. We succeeded in finding a simple Kambe-type resolution of the Heisenberg spin Hamiltonian for the rather complex case of the heptanuclear. In a similar manner, the weak intermolecular coupling of two trimer units (aside from the strong exchange inside triangles) was resolved by closed energy formulas. The hexanuclear can be legitimately proposed as a case of coordination-based aromaticity, since the phenomenology of the six-spins problem resembles the bonding in benzene. The Broken-Symmetry Density Functional Theory (BS-DFT) calculations are non-trivial results, being intrinsically difficult at high nuclearities.

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Section: Materials and Physical Measurementsmentioning

confidence: 99%

“…Our attention was focused on the reaction of copper(II) carboxylates with pyrazole derivatives, 3,5-dimethyl-4-nitro-pyrazole (dmnpz), observing that different nuclearities and topologies depend on the employed solvent. The pyrazole (dmnpz) was synthesized according to Scheme 2 [33][34][35].…”

Section: Introductionmentioning

confidence: 99%

New Syntheses, Analytic Spin Hamiltonians, Structural and Computational Characterization for a Series of Tri-, Hexa- and Hepta-Nuclear Copper (II) Complexes with Prototypic Patterns

Toader¹,

Buta²,

Cimpoesu³

et al. 2021

Chemistry

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Ueber den aromatischen Charakter der Pyrazole

Knorr

1895

Ber. Dtsch. Chem. Ges.

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Antipyrin, durch Reduction mit Natrium und Alkohol das 1-Pbenylhnethylpyrazolin gewonnen wurden. Diese Umwandlungsproducte wurden mit grosser Sorgfalt identificirt. 4-B i s-1-phenyl-2-methyl-5-methoxypyrazol entsteht in analoger Weise aus dern Bispbenylmethylpyrazolon durch Einwirkung von Natriummethylat und Jodmethyl neben dem Bisantipyrin. Die Verbindung schmilzt aus Alkohol umkrgstallisirt bei 186 bis 1870. Analyse : Ber. fiir CalHmN4 02. Procente: N 14.97. Gef.)) 14.76. Sie lasst sicb in gleicber Weise wie die oben bescbriebenen Verbindungen umwandeln. 2. B. entstebt bei der Reduction mit Natrium und Alkohol ein Pyrazolin (wohl das 4-Bis-1-phenyl-3methylpyrazolin), welcbes bei 100 mm Druck bei circa 300° destillirt. Analyse: Ber. f i r G~H B N~. Procente: N 14.46. Gef. * 14.39. Schliesslich sei bemerkt, dass aucb eine schon vor sehr langer Zeit') dargestellte Substanz (Scbmp. 145 O), niimlich das Conden

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Pyrazol aus Acetylen und Diazomethan

Pechmann

1898

Ber. Dtsch. Chem. Ges.

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VI. Darstellung und Derivate des freien Pyrazols

Cited by 19 publications

References 1 publication

New Syntheses, Analytic Spin Hamiltonians, Structural and Computational Characterization for a Series of Tri-, Hexa- and Hepta-Nuclear Copper (II) Complexes with Prototypic Patterns

New Syntheses, Analytic Spin Hamiltonians, Structural and Computational Characterization for a Series of Tri-, Hexa- and Hepta-Nuclear Copper (II) Complexes with Prototypic Patterns

Ueber den aromatischen Charakter der Pyrazole

Pyrazol aus Acetylen und Diazomethan

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