Copper(II) complexes with a novel tris(3,5-diisopropyl-1-pyrazolyl)methane ligand, [Cu(X 2 ){HC(3,5- i Pr 2 pz) 3 }] (X Cl and NO 3 )

Fujisawa, Kiyoshi; Ono, Tetsuya; Aoki, Hijiri; Ishikawa, Yoko; Miyashita, Yoshitaro; Okamoto, Ken‐ichi; Nakazawa, Hiroshi; Higashimura, Hideyuki

doi:10.1016/j.inoche.2003.12.005

Cited by 22 publications

(8 citation statements)

References 12 publications

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“…In [Cu(L1‘ ‘)Cl 2 ] ( 7 ), the copper(II) ion is four-coordinate with L1‘ ‘ and two chloride ions bound (Figure , bottom right). The average Cu−Cl bond distance of 2.225(2) Å in 7 is slightly shorter than that of 2.258 Å in the five-coordinate complex [Cu(L1‘)Cl 2 ] with a neutral tridentate ligand …”

Section: Resultsmentioning

confidence: 85%

Mononuclear and Binuclear Copper(I) Complexes Ligated by Bis(3,5-diisopropyl-1-pyrazolyl)methane: Insight into the Fundamental Coordination Chemistry of Three-Coordinate Copper(I) Complexes with a Neutral Coligand

et al. 2007

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By using the neutral bidentate nitrogen-containing ligand, bis(3,5-diisopropyl-1-pyrazolyl)methane (L1' '), the copper(I) complexes [Cu(L1' ')2](CuCl2) (1CuCl2), [Cu(L1' ')2](ClO4) (1ClO4), [Cu(L1' ')]2(ClO4)2 (2ClO4), [Cu(L1' ')]2(BF4)2 (2BF4), [Cu(L1' ')(NCMe)](PF6) (3PF6), [Cu(L1' ')(PPh3)](ClO4) (4ClO4), [Cu(L1' ')(PPh3)](PF6) (4PF6), [{Cu(L1' ')(CO)}2(mu-ClO4)](ClO4) (5ClO4), and the copper(II) complexes [{Cu(L1' ')}2(mu-OH)2(mu-ClO4)2] (6), and [Cu(L1' ')Cl2] (7) were systematically synthesized and fully characterized by X-ray crystallography and by IR and 1H NMR spectroscopy. In the case of copper(II), ESR spectroscopy was also applied. In comparison with the related neutral tridentate ligand L1', bis-chelated copper(I) complexes and binuclear linear-coordinated copper(I) complexes are easy to obtain with L1' ', like 1CuCl2, 1ClO4, 2ClO4, and 2BF4. Importantly, stronger and bulkier ligands such as acetonitrile (3PF6) and especially triphenylphosphine (4ClO4 and 4PF6) generate three-coordinate structures with a trigonal-planar geometry. Surprisingly, for the smaller ligand carbon monoxide, a mononuclear three-coordinate structure is very unstable, leading to the formation of a binuclear complex (5ClO4) with one bridging perchlorate anion, such that the copper(I) centers are four-coordinate. The same tendency is observed for the copper(II) bis(mu-hydroxo) compounds 6, which is additionally bridged by two perchlorate anions. Both copper(II) complexes 6 and 7 were obtained by molecular O2 oxidation of the corresponding copper(I) complexes. A comparison of the new copper(I) triphenylphosphine complexes 4ClO4 and 4PF6 with corresponding species obtained with the related tridentate ligands L1' and L1 (8ClO4 and 9, respectively) reveals surprisingly small differences in their spectroscopic properties. Density functional theory (DFT) calculations are used to shed light on the differences in bonding in these compounds and the spectral assignments. Finally, the reactivity of the different bis(pyrazolyl)methane complexes obtained here toward PPh3, CO, and O2 is discussed.

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Section: Resultsmentioning

confidence: 85%

Mononuclear and Binuclear Copper(I) Complexes Ligated by Bis(3,5-diisopropyl-1-pyrazolyl)methane: Insight into the Fundamental Coordination Chemistry of Three-Coordinate Copper(I) Complexes with a Neutral Coligand

et al. 2007

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“…Eluguero and co-workers and Reger and co-workers have developed improved procedures for the synthesis of these N3 tripodal ligands. The preparation of the highly hindered 3,5-disubstituted tris(pyrazolyl)methane ligands, L1‘ and L3‘, under solid−liquid phase transfer conditions using an autoclave was reported recently for the first time . The reactions of 3,5- i Pr 2 -pzH and 3- t Bu-5- i Pr-pzH with CHCl 3 in the presence of anhydrous potassium carbonate (base) and tetrabutylammonium hydrogensulfate (catalyst) were carried out as shown in eq 2 over 3 days for L1‘ and over 15 days for L3‘ at ∼95 °C (inner temperature of the autoclave), which was needed for the reaction to complete.…”

Section: Resultsmentioning

confidence: 99%

“…HC(3,5- i Pr 2 pz) 3 , Tris(3,5-diisopropyl-1-pyrazolyl)methane, L1 ‘ . Chloroform (130 mL) was added to a mixture of 3,5-diisopropylpyrazole 13,14 (7.28 g, 48.0 mmol), potassium carbonate (13.3 g, 96.0 mmol), and tetrabutylammonium hydrogensulfate (2.01 g, 5.90 mmol), and the mixture was bubbled with argon for 15 min. This solution was then heated and gently refluxed for 3 days at ∼95 °C (inner temperature of the autoclave).…”

Section: Methodsmentioning

confidence: 99%

Structural and Electronic Differences of Copper(I) Complexes with Tris(pyrazolyl)methane and Hydrotris(pyrazolyl)borate Ligands

et al. 2006

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Copper(I) complexes with tripodal nitrogen-containing neutral ligands such as tris(3,5-diisopropyl-1-pyrazolyl)methane (L1') and tris(3-tertiary-butyl-5-isopropyl-1-pyrazolyl)methane (L3'), and with corresponding anionic ligands such as hydrotris(3,5-diisopropyl-1-pyrazolyl)borate (L1-) and hydrotris(3-tertiary-butyl-5-isopropyl-1-pyrazolyl)borate (L3-) were synthesized and structurally characterized. Copper(I) complexes [Cu(L1')Cl] (1), [Cu(L1')(OClO3)] (2), [Cu(L1')(NCMe)](PF6) (3a), [Cu(L1')(NCMe)](ClO4) (3b), [Cu(L1')(CO)](PF6) (4a), and [Cu(L1')(CO)](ClO4) (4b) were prepared using the ligand L1'. Copper(I) complexes [Cu(L3')Cl] (5) and [Cu(L3')(NCMe)](PF6) (6) with the ligand L3' were also synthesized. Copper(I) complexes [Cu(L1)(NCMe)] (7) and [Cu(L1)(CO)] (8) were prepared using the anionic ligand L1-. Finally, copper(I) complexes with anionic ligand L3- and acetonitrile (9) and carbon monoxide (10) were synthesized. The complexes obtained were fully characterized by IR, far-IR, 1H NMR, and 13C NMR spectroscopy. The structures of both ligands, L1' and L3', and of complexes 1, 2, 3a, 3b, 4a, 4b, 5, 6, 7, and 10 were determined by X-ray crystallography. The effects of the differences in (a) the fourth ligand and the counteranion, (b) the steric hindrance at the third position of the pyrazolyl rings, and most importantly, (c) the charge of the N3 type ligands, on the structures, spectroscopic properties, and reactivities of the copper(I) complexes are discussed. The observed differences in the reactivities toward O2 of the copper(I) acetonitrile complexes are traced back to differences in the oxidation potentials determined by cyclic voltammetry. A special focus is set on the carbonyl complexes, where the 13C NMR and vibrational data are presented. Density functional theory (DFT) calculations are used to shed light on the differences in CO bonding in the compounds with neutral and anionic N3 ligands. In correlation with the vibrational and electrochemical data of these complexes, it is demonstrated that the C-O stretching vibration is a sensitive probe for the "electron richness" of copper(I) in these compounds.

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“…Samples. [Cu(O 2 ){HB(3-Ad-5- i Prpz) 3 }] (where HB(3-Ad-5- i Prpz) 3 = hydrotris(3-adamantyl-5-isopropyl-1-pyrazolyl)borate, 1 L) and [Cu(O 2 )(β-diketiminate)] (where β-diketiminate = N , N ‘-bis(2,6-diisopropylphenyl)-3,5-methyldiiminato, 2 L) have been studied as analogues of 1 and 2 since they have greater thermal stability. The [ 1 LCu(O 2 )] ( 1 ) 19 and [ 2 LCu(O 2 )] ( 2 ) 26 complexes were synthesized as previously described.…”

Section: Methodsmentioning

confidence: 99%

X-ray Absorption Edge Spectroscopy and Computational Studies on LCuO₂ Species: Superoxide−Cu^II versus Peroxide−Cu^III Bonding

et al. 2006

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The geometric and electronic structures of two mononuclear CuO2 complexes, [Cu(O2){HB(3-Ad-5-(i)Prpz)3}] (1) and [Cu(O2)(beta-diketiminate)] (2), have been evaluated using Cu K- and L-edge X-ray absorption spectroscopy (XAS) studies in combination with valence bond configuration interaction (VBCI) simulations and spin-unrestricted broken symmetry density functional theory (DFT) calculations. Cu K- and L-edge XAS data indicate the Cu(II) and Cu(III) nature of 1 and 2, respectively. The total integrated intensity under the L-edges shows that the 's in 1 and 2 contain 20% and 28% Cu character, respectively, indicative of very covalent ground states in both complexes, although more so in 1. Two-state VBCI simulations also indicate that the ground state in 2 has more Cu (/3d8) character. DFT calculations show that the in both complexes is dominated by O2(n-) character, although the O2(n-) character is higher in 1. It is shown that the ligand L plays an important role in modulating Cu-O2 bonding in these LCuO2 systems and tunes the ground states of 1 and 2 to have dominant Cu(II)-superoxide-like and Cu(III)-peroxide-like character, respectively. The contributions of ligand field (LF) and the charge on the absorbing atom in the molecule (Q(mol)M) to L- and K-edge energy shifts are evaluated using DFT and time-dependent DFT calculations. It is found that LF makes a dominant contribution to the edge energy shift, while the effect of Q(mol)M is minor. The charge on the Cu in the Cu(III) complex is found to be similar to that in Cu(II) complexes, which indicates a much stronger interaction with the ligand, leading to extensive charge transfer.

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Copper(II) complexes with a novel tris(3,5-diisopropyl-1-pyrazolyl)methane ligand, [Cu(X 2 ){HC(3,5- i Pr 2 pz) 3 }] (X Cl and NO 3 )

Cited by 22 publications

References 12 publications

Mononuclear and Binuclear Copper(I) Complexes Ligated by Bis(3,5-diisopropyl-1-pyrazolyl)methane: Insight into the Fundamental Coordination Chemistry of Three-Coordinate Copper(I) Complexes with a Neutral Coligand

Mononuclear and Binuclear Copper(I) Complexes Ligated by Bis(3,5-diisopropyl-1-pyrazolyl)methane: Insight into the Fundamental Coordination Chemistry of Three-Coordinate Copper(I) Complexes with a Neutral Coligand

Structural and Electronic Differences of Copper(I) Complexes with Tris(pyrazolyl)methane and Hydrotris(pyrazolyl)borate Ligands

X-ray Absorption Edge Spectroscopy and Computational Studies on LCuO₂ Species: Superoxide−Cu^II versus Peroxide−Cu^III Bonding

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Copper(II) complexes with a novel tris(3,5-diisopropyl-1-pyrazolyl)methane ligand, [Cu(X 2 ){HC(3,5- i Pr 2 pz) 3 }] (X Cl and NO 3 )

Cited by 22 publications

References 12 publications

Mononuclear and Binuclear Copper(I) Complexes Ligated by Bis(3,5-diisopropyl-1-pyrazolyl)methane: Insight into the Fundamental Coordination Chemistry of Three-Coordinate Copper(I) Complexes with a Neutral Coligand

Mononuclear and Binuclear Copper(I) Complexes Ligated by Bis(3,5-diisopropyl-1-pyrazolyl)methane: Insight into the Fundamental Coordination Chemistry of Three-Coordinate Copper(I) Complexes with a Neutral Coligand

Structural and Electronic Differences of Copper(I) Complexes with Tris(pyrazolyl)methane and Hydrotris(pyrazolyl)borate Ligands

X-ray Absorption Edge Spectroscopy and Computational Studies on LCuO2 Species: Superoxide−CuII versus Peroxide−CuIII Bonding

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X-ray Absorption Edge Spectroscopy and Computational Studies on LCuO₂ Species: Superoxide−Cu^II versus Peroxide−Cu^III Bonding