Two complexes of CuBr<sub>2</sub>with 5-<i>tert</i>-butylpyrazole

Liu, Xiaoming; Kilner, Colin A.; Halcrow, Malcolm A.

doi:10.1107/s0108270101012653

Cited by 8 publications

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References 13 publications

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“…The long reaction time seems necessary to maximize the yields of 1±3, and to avoid contamination of the product by the corresponding monomers [CuX 2 (Hpz tBu ) 4 ]. [20] Pure 1 and 2 can be recrystallized cleanly from CH 2 Cl 2 ±pentane mixtures; recrystallization of 3 results in partial decomposition of the sample. Importantly, 1±3 can only be prepared by slow crystallization.…”

Section: Resultsmentioning

confidence: 99%

Reactions of Copper(II) Salts with 3{5}‐tert‐Butylpyrazole: Double‐Cubane Complexes with Bound Exogenous Anions, and a Novel Pyrazole Coordination Mode

Liu

McAllister

Miranda

et al. 2004

Chemistry A European J

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Reaction of CuX(2) (X(-)=Cl(-), Br(-), NO(3) (-)), NaOH, and 3[5]-tert-butylpyrazole (Hpz(tBu)) in a 1:1:2 molar ratio in MeOH at 293 K for three days affords [[Cu(3)(Hpz(tBu))(6)(mu(3)-X)(mu(3)-OH)(3)](2)Cu]X(6) (X(-)=Cl(-), 1; X(-)=Br(-), 2; X(-)=NO(3)(-), 3) in moderate yields. These compounds contain a centrosymmetric, vertex-sharing double-cubane [[Cu(3)(Hpz(tBu))(6)(mu(3)-X)(mu(3)-OH)(3)](2)Cu](6+) core, surrounded by a belt of six hydrogen-bonded X(-) ions. For 1 and 2, the ring of guest anions has near C(3) symmetry, that is slightly distorted owing to the axis of Jahn-Teller elongation at the central Cu ion. For 3 only, the NO(3)(-) guest ions are crystallographically disordered, reflecting their poor complimentarity with complex host. A similar reaction employing CuF(2) yields [[Cu(3)(Hpz(tBu))(4)(mu-pz(tBu))(2)(mu-F)(2)(mu(3)-F)](2)]F(2) (4), whose structure contains a cyclic hexacopper core with approximate C(2v) symmetry. Finally, an analogous reaction using Cu(NCS)(2) gives a mixture of trans-[Cu(NCS)(2)(Hpz(tBu))(2)] (5) and [Cu(2)(NCS)(2)(mu-pz(tBu))(2)(mu-Hpz(tBu))(Hpz(tBu))(2)] (6). The latter compound contains a Hpzt(Bu) ligand bridging the two Cu ions in an unusual kappa(1),mu-coordination mode. The variable temperature magnetic properties of 1-3 show antiferromagnetic behavior, leading to a S=1/2 ground state in which the seven copper(II) ions are associated into three mutually independent distinct spin systems. In confirmation of this interpretation, Q-band EPR spectra of solid 1 and 2 at 5 K also demonstrate a S= 1/2 spin system and exhibit hyperfine coupling to three (63,65)Cu nuclei. Unusually, the coupling is manifest as an eight-line splitting of the parallel feature, rather than the usual 10 lines. This has been rationalized by a spin-projection calculation, and results from the relative magnitudes of coupling to the three Cu nuclei. UV/Vis and mass spectrometric data show that 1-4 decompose to lower nuclearity species in solution.

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Section: Resultsmentioning

confidence: 99%

Reactions of Copper(II) Salts with 3{5}‐tert‐Butylpyrazole: Double‐Cubane Complexes with Bound Exogenous Anions, and a Novel Pyrazole Coordination Mode

Liu

McAllister

Miranda

et al. 2004

Chemistry A European J

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“…Pyrazoles can form structures of various nuclearities, ranging from mononuclear (Mighell et al, 1975;Liu et al, 2001;Małecka et al, 2003) to polynuclear complexes (He, 2011;Contaldi et al, 2009;Chandrasekhar et al, 2008) and metallacycles (Vynohradov et al, 2020a;Surmann et al, 2016;Galassi et al, 2012) with specific molecular topologies. By performing the synthesis of metal complexes by oxidative dissolution of metals, commonly known as direct synthesis (Kokozay et al, 2018;Plyuta et al, 2020;Sirenko et al, 2020;Li et al, 2021), copper can be introduced in a zerovalent state.…”

Section: Chemical Contextmentioning

confidence: 99%

Crystal structure and Hirshfeld surface analysis of di-μ-chlorido-bis[(acetonitrile-κN)chlorido(ethyl 5-methyl-1H-pyrazole-3-carboxylate-κ² N ²,O)copper(II)]

et al. 2021

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The title compound, [Cu2Cl4(C5H10N2O2)2(CH3CN)2] or [Cu2(μ2-Cl)2(CH3—Pz-COOCH2CH3)2Cl2(CH3CN)2], was synthesized using a one-pot reaction of copper powder, copper(II) chloride dihydrate and ethyl 5-methyl-1H-pyrazole-3-carboxylate (CH3—Pz-COOCH2CH3) in acetonitrile under ambient conditions. This complex consists of discrete binuclear molecules with a {Cu2(μ2-Cl)2} core, in which the Cu...Cu distance is 3.8002 (7) Å. The pyrazole-based ligands are bidentate coordinated, leading to the formation of two five-membered chelate rings. The coordination geometry of both copper atoms (ON2Cl3) can be described as distorted octahedral on account of the acetonitrile coordination. A Hirshfeld surface analysis suggests that the most important contributions to the surface contacts are from H...H (40%), H...Cl/Cl...H (24.3%), H...O/O...H (11.8%), H...C/C...H (9.2%) and H...N/N...H (8.3%) interactions.

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“…There have been a few crystal structures reported to date for four-coordinate Cu complexes containing two coordinated pyrazoles and two coordinated halides, viz. dichlorobis(1phenyl-3,5-dimethylpyrazole)copper(II) (Francisco et al, 1980;Costa-Filho et al, 1999), dibromobis(3,5-diphenylpyrazole)copper(II) (Murray et al, 1988), dibromobis(1phenyl-3,5-dimethylpyrazole)copper(II) (Costa-Filho et al, 1999), trans-dibromobis(5À t-butylpyrazole)copper(II) (Liu et al, 2001), bis(3-amino-4-acetyl-5-methylpyrazole)dichloro copper(II) (Hergold-Brundic et al, 1991) and trans-bis(4bromopyrazole)dichlorocopper(II) (Valle et al, 1995). The bond lengths in the title compound are comparable with those in these structures, which show Cu-N bond lengths ranging from 1.94 to 2.02 Å and Cu-Cl bond lengths ranging from 2.23 to 2.34 Å .…”

Section: Commentmentioning

confidence: 99%

Dichlorobis(3,5-dimethylpyrazole)copper(II)

Zhao

Eichhorn

2005

Acta Cryst E

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Two complexes of CuBr₂with 5-tert-butylpyrazole

Cited by 8 publications

References 13 publications

Reactions of Copper(II) Salts with 3{5}‐tert‐Butylpyrazole: Double‐Cubane Complexes with Bound Exogenous Anions, and a Novel Pyrazole Coordination Mode

Reactions of Copper(II) Salts with 3{5}‐tert‐Butylpyrazole: Double‐Cubane Complexes with Bound Exogenous Anions, and a Novel Pyrazole Coordination Mode

Crystal structure and Hirshfeld surface analysis of di-μ-chlorido-bis[(acetonitrile-κN)chlorido(ethyl 5-methyl-1H-pyrazole-3-carboxylate-κ² N ²,O)copper(II)]

Dichlorobis(3,5-dimethylpyrazole)copper(II)

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Two complexes of CuBr2with 5-tert-butylpyrazole

Cited by 8 publications

References 13 publications

Reactions of Copper(II) Salts with 3{5}‐tert‐Butylpyrazole: Double‐Cubane Complexes with Bound Exogenous Anions, and a Novel Pyrazole Coordination Mode

Reactions of Copper(II) Salts with 3{5}‐tert‐Butylpyrazole: Double‐Cubane Complexes with Bound Exogenous Anions, and a Novel Pyrazole Coordination Mode

Crystal structure and Hirshfeld surface analysis of di-μ-chlorido-bis[(acetonitrile-κN)chlorido(ethyl 5-methyl-1H-pyrazole-3-carboxylate-κ2 N 2,O)copper(II)]

Dichlorobis(3,5-dimethylpyrazole)copper(II)

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Two complexes of CuBr₂with 5-tert-butylpyrazole

Crystal structure and Hirshfeld surface analysis of di-μ-chlorido-bis[(acetonitrile-κN)chlorido(ethyl 5-methyl-1H-pyrazole-3-carboxylate-κ² N ²,O)copper(II)]