Synthesis, structure, and spectroscopic properties of an unusual copper(I) dimer having imidazole ligands. A model for the carbonyl derivative of hemocyanin and implications for the structure of deoxyhemocyanin

Sorrell, Thomas N.; Borovik, A. S.

doi:10.1021/ja00248a020

Cited by 91 publications

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“…The only model complexes that exhibit such low values are those derived from nonchelating imidazoles (2059 ± 2067 cm À1 ), [68] or from the anionic tris(pyrazolyl)borate ligand. [57,58,62,63] On the other hand, for complexes obtained with the neutral tris(imidazolyl)methoxymethane (n CO 2080 cm À1 ) [59] and tris(imidazolyl)phosphane (n CO 2083 ± 2086 cm À1 ) [60] tripods, the CO stretches are more energetic. Complexes 4, although structurally very similar to the biological systems, display n CO values that are % 40 cm À1 higher.…”

Section: Discussionmentioning

confidence: 99%

Biomimetic Copper(I)-CO Complexes: A Structural and Dynamic Study of a Calix[6]arene-Based Supramolecular System

et al. 2000

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Four novel calix[6]arene-based cuprous complexes are described. They present a biomimetic tris(imidazole) coordination core associated with a hydrophobic cavity that wraps the apical binding site. Each differs from the other by the methyl or ethyl substituents present on the phenoxyl groups (OR1) and on the imidazole arms (NR2) of the calix[6]arene structure. In solution, stable CO complexes were obtained. We have investigated their geometrical and dynamic properties with respect to the steric demand. IR and NMR studies revealed that, in solution, these complexes adopted two distinct conformations. The preferred conformation was dictated only by the size of the OR1 group. When R1 was an ethyl group, the complex preferentially adopted a flattened C3-symmetrical structure. The corresponding helical enantiomers were in conformational equilibrium, which, however, was slow on the 1H NMR time scale at -80 degrees C. When R1 was a methyl group, the low-temperature NMR spectra revealed the partial inclusion of one tBu group. The complex wobbled between three dissymmetric but equivalent conformations. Hence, small differences in the steric demand of the calixarene's skeleton changed the geometry and dynamics of the system. Indeed, this supramolecular control was promoted by the strong conformational coupling between the metal center and the host structure. Interestingly, this was not only the result of a covalent preorganization, but also stemmed from weak interactions within the hydrophobic pocket. The vibrational spectra of the bound CO were revealed to be a sensitive gauge of this supramolecular behavior, similar to copper proteins in which allosteric effects are common.

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Section: Discussionmentioning

confidence: 99%

Biomimetic Copper(I)-CO Complexes: A Structural and Dynamic Study of a Calix[6]arene-Based Supramolecular System

et al. 2000

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“…Three-coordinate copper() has also been detected in polymeric systems with different ligands. [14,21,22] The dimers derived from tris-(pyrazolyl)borate [23] and tris(imidazole)methoxymethane [24] are rare examples of tricoordinate Cu I complexes without bridges between the metals. 4 ](ClO 4 ) and ClPhtrz ligand in acetonitrile was allowed to stand for a long time (about one month) light-yellow crystals of 2 were formed.…”

Section: X-ray Structure Ofmentioning

confidence: 99%

Synthesis, Crystallographic and Spectroscopic Studies of Dimeric Cu^I Complexes with Schiff‐Base‐Containing Triazole Ligands

2003

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New CuI complexes of the Schiff‐base‐containing triazole ligands N‐[(E)‐(4‐chlorophenyl)methylidene]‐4H‐1,2,4‐triazol‐4‐amine (ClPhtrz) and N‐[(E)‐phenylmethylidene]‐4H‐1,2,4‐triazol‐4‐amine (Phtrz) have been synthesised and characterised. Depending on the reaction conditions ClPhtrz forms two different dimeric complexes 1 and 2. X‐ray crystallography revealed that each copper centre exhibits a planar trigonal coordination in 1, while the tetrahedral coordination sphere of the copper centre in 2 is completed by a solvent molecule. In dimeric complex 3 the tetrahedral coordination of the CuI ions is formed by two monodentate and two bidentate (bridging) Phtrz ligands. Complexes 1−3 are unstable and easily lose coordinating and/or solvating acetonitrile molecules giving 4 (from 1 and 2) and 5 (from 3). On the basis of ESI MS and 1H NMR and UV/Vis spectroscopy, it was shown that dimeric complexes 1−5 do not survive upon dissolution and dissociate rapidly forming mainly a 1:2 monomeric complex, along with a minor 1:1 complex. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)

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“…[27] Related dinuclear Cu(I) complexes have been recently reported with timm derivatives. [28] Reactions of L with the Cu(I) and Cu(II) precursors afforded 1:1 ligand:metal complexes even with addition of excess ligand.…”

Section: Discussionmentioning

confidence: 99%

Synthesis, characterization and copper chemistry of a non-symmetric phenanthroline ligand: 2-Methyl-9-(3,5-dimethyl-N-pyrazolylmethyl)-1,10-phenanthroline

Masood

Storr

Stack

2008

Inorganica Chimica Acta

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The synthesis of an unsymmetrical phenanthroline based ligand, 2-methyl-9-(3,5-dimethylpyrazolylmethyl)-1,10-phenanthroline (L), and its cupric [Cu(II)] (1) and cuprous [Cu(I)] (2) complexes, are reported. The X-ray structures of each of these Cu complexes show distinct changes in coordination environments consistent with the geometrical preferences of the two oxidation states. In the solid state the Cu(II) complex (1) adopts a geometry best described as trigonal bipyramidal, while the Cu(I) complex (2) consists of a single dicationic dimer in which the ligand bridges between two copper ions, separated by 4.26 Å. The two Cu(I) coordination sites differ in 2 with one copper center complexed in a trigonal planar geometry and the other copper in a distorted tetrahedral environment; the latter coordination results from an additional CH 3 CN ligand. Complex 1 exhibits a reversible redox process at −0.34 V vs. Fc/Fc + in CH 3 CN, attributable to the Cu 2+ / Cu + couple, while the dimeric Cu(I) complex (2) is resistant to oxidation on the CV timescale. Over minutes however, complex 1 does oxidize in the presence of dioxygen to 2 in CH 3 CN.

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Synthesis, structure, and spectroscopic properties of an unusual copper(I) dimer having imidazole ligands. A model for the carbonyl derivative of hemocyanin and implications for the structure of deoxyhemocyanin

Cited by 91 publications

References 0 publications

Biomimetic Copper(I)-CO Complexes: A Structural and Dynamic Study of a Calix[6]arene-Based Supramolecular System

Biomimetic Copper(I)-CO Complexes: A Structural and Dynamic Study of a Calix[6]arene-Based Supramolecular System

Synthesis, Crystallographic and Spectroscopic Studies of Dimeric Cu^I Complexes with Schiff‐Base‐Containing Triazole Ligands

Synthesis, characterization and copper chemistry of a non-symmetric phenanthroline ligand: 2-Methyl-9-(3,5-dimethyl-N-pyrazolylmethyl)-1,10-phenanthroline

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Synthesis, structure, and spectroscopic properties of an unusual copper(I) dimer having imidazole ligands. A model for the carbonyl derivative of hemocyanin and implications for the structure of deoxyhemocyanin

Cited by 91 publications

References 0 publications

Biomimetic Copper(I)-CO Complexes: A Structural and Dynamic Study of a Calix[6]arene-Based Supramolecular System

Biomimetic Copper(I)-CO Complexes: A Structural and Dynamic Study of a Calix[6]arene-Based Supramolecular System

Synthesis, Crystallographic and Spectroscopic Studies of Dimeric CuI Complexes with Schiff‐Base‐Containing Triazole Ligands

Synthesis, characterization and copper chemistry of a non-symmetric phenanthroline ligand: 2-Methyl-9-(3,5-dimethyl-N-pyrazolylmethyl)-1,10-phenanthroline

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Synthesis, Crystallographic and Spectroscopic Studies of Dimeric Cu^I Complexes with Schiff‐Base‐Containing Triazole Ligands