CuI Complexes with N,N′,S,S′ Scorpionate Ligands: Evidence for Dimer−Monomer Equilibria

Gennari, Marcello; Tegoni, Matteo; Lanfranchi, Maurizio; Pellinghelli, Maria Angela; Giannetto, Marco; Marchiò, Luciano

doi:10.1021/ic702108x

Cited by 19 publications

(20 citation statements)

References 50 publications

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“…In fact, this type of copper(I) complex dimerization in the solid state has been observed previously for a number of three- or four-coordinate complexes, with a thioether donor and even with all nitrogen donor ligands. 6,9b,10,16,17 …”

Section: Resultsmentioning

confidence: 99%

Tuning of the Copper–Thioether Bond in Tetradentate N₃S_(thioether) Ligands; O–O Bond Reductive Cleavage via a [Cu^II₂(μ-1,2-peroxo)]²⁺/[Cu^III₂(μ-oxo)₂]²⁺ Equilibrium

et al. 2014

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Current interest in copper/dioxygen reactivity includes the influence of thioether sulfur ligation, as it concerns the formation, structures, and properties of derived copper-dioxygen complexes. Here, we report on the chemistry of {L-CuI}2-(O2) species L = DMMESE, DMMESP, and DMMESDP, which are N3S(thioether)-based ligands varied in the nature of a substituent on the S atom, along with a related N3O(ether) (EOE) ligand. CuI and CuII complexes have been synthesized and crystallographically characterized. Copper(I) complexes are dimeric in the solid state, [{L-CuI}2](B(C6F5)4)2, however are shown by diffusion-ordered NMR spectroscopy to be mononuclear in solution. Copper(II) complexes with a general formulation [L-CuII(X)]n+ {X = ClO4–, n = 1, or X = H2O, n = 2} exhibit distorted square pyramidal coordination geometries and progressively weaker axial thioether ligation across the series. Oxygenation (−130 °C) of {(DMMESE)CuI}+ results in the formation of a trans-μ-1,2-peroxodicopper(II) species [{(DMMESE)CuII}2(μ-1,2-O22–)]2+ (1P). Weakening the Cu–S bond via a change to the thioether donor found in DMMESP leads to the initial formation of [{(DMMESP)CuII}2(μ-1,2-O22–)]2+ (2P) that subsequently isomerizes to a bis-μ-oxodicopper(III) complex, [{(DMMESP)CuIII}2(μ-O2–)2]2+ (2O), with 2P and 2O in equilibrium (Keq = [2O]/[2P] = 2.6 at −130 °C). Formulations for these Cu/O2 adducts were confirmed by resonance Raman (rR) spectroscopy. This solution mixture is sensitive to the addition of methylsulfonate, which shifts the equilibrium toward the bis-μ-oxo isomer. Further weakening of the Cu–S bond in DMMESDP or substitution with an ether donor in DMMEOE leads to only a bis-μ-oxo species (3O and 4O, respectively). Reactivity studies indicate that the bis-μ-oxodicopper(III) species (2O, 3O) and not the trans-peroxo isomers (1P and 2P) are responsible for the observed ligand sulfoxidation. Our findings concerning the existence of the 2P/2O equilibrium contrast with previously established ligand-CuI/O2 reactivity and possible implications are discussed.

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Section: Resultsmentioning

confidence: 99%

Tuning of the Copper–Thioether Bond in Tetradentate N₃S_(thioether) Ligands; O–O Bond Reductive Cleavage via a [Cu^II₂(μ-1,2-peroxo)]²⁺/[Cu^III₂(μ-oxo)₂]²⁺ Equilibrium

et al. 2014

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“…At low temperatures, the 1 H and 13 C NMR spectra of the complexes (1)(2)(3)(4)(5) indicate the presence of two invertomers a and b, of similar abundance. Each of them gives two sets of signals, in that the N,S-chelation makes non-equivalent the dithioether protons and carbons which are equivalent in the free ligands.…”

Section: Discussionmentioning

confidence: 98%

“…Di-2-pyridyl sulfide (dps) [31], di-2-pyrimidyl sulfide (dprs) [7], [Ru(dps) 2 Conductivity measurements were done on a Metrohm 644 conductometer. Infrared spectra were recorded on a Perkin Elmer RX I FT-IR spectrophotometer with samples as Nujol mulls placed between KBr plates and the 1 H and 13 C NMR spectra on a Bruker AMX 300 spectrometer.…”

Section: Methodsmentioning

confidence: 99%

“…The coordination chemistry of hybrid ligands, especially those with labile or hemilabile functions to promote dynamic properties such as solution equilibria, fluxional processes and catalytic reversibility, is an active area of research [1][2][3][4][5][6]. Our recent NMR studies concerned the solution stereodynamics of ruthenium(II) complexes of a range of hybrid sulfur nitrogen ligands based on pyridine or pyrimidine [7][8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

“…This type of process was previously studied in the terpyridine complexes, in which the exchange occurs between pendant and coordinated pyridyl rings, and then in metal complexes containing polydentate sulfur nitrogen ligands if restricted to the bidentate bonding mode [16][17][18]. The proposed mechanisms were as follows: (1) the 'tick-tock twist' mechanism, involving a pseudo terdentate bonding mode of the ligand in the transition state [19][20][21][22][23][24][25]; (2) the 'rotation' mechanism involving the loosening of the outer metal-donor atom bond Electronic supplementary material The online version of this article (doi:10.1007/s11243-009-9308-7) contains supplementary material, which is available to authorized users.…”

Section: Introductionmentioning

confidence: 99%

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Fluxional rearrangement in congested ruthenium(II) complexes containing pyrimidine- and/or pyridine-based dithioether ligands

Tresoldí

Pietro

Drommi

et al. 2009

Transition Met Chem

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The solvento species obtained by the treatment of cis-RuCl 2 (N,N-L) 2 [L = di-2-pyridyl sulfide (dps), di-2-pyrimidyl sulfide (dprs)] with AgPF 6 , reacted with dithioethers L 0 [L 0 = 2,6-bis(2-pyridylthiomethyl)pyridine (pytmp), 2,6-bis (2-pyrimidylthiomethyl)pyridine (prtmp) and 2,6-bis{2-(4-methyl) pyrimidylthiomethyl} pyridine (mprtmp)] to afford the compounds [Ru(N,N-L) 2 (N,S-L 0 )][PF 6 ] 2 . The 1 H NMR spectra indicate that L 0 is chelated through S and N atoms with the formation of a four-membered ring. As a consequence, the ruthenium and sulfur atoms are stereogenic centers with D and K and (R) and (S) configurations, respectively. NMR spectra, at low temperatures, show that two invertomers, of similar abundance, as enantiomeric couples DS, KR and DR, KS are present. In the methylene region, four AB systems are observed that in both the species contain two non-equivalent methylene groups. Variable-temperature NMR spectra and EXSY experiments show that the sulfur inversion produces an exchange between the invertomers. The one-dimensional band-shape analysis of the exchanging methylene signals showed that the energy barriers for the process are in the 43-52 kJ mol -1 range. The possible mechanisms of the sulfur inversion are discussed.

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A Ruthenium(II)–Copper(II) Dyad for the Photocatalytic Oxygenation of Organic Substrates Mediated by Dioxygen Activation

et al. 2015

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Dioxygen activation by copper complexes is av aluable method to achieve oxidation reactions for sustainable chemistry.T he development of ac atalytic system requires regeneration of the From an environmental point of view,t here is ag rowing interest in designing catalysts capable of using O 2 as oxygen atom source to perform oxidation reactions to avoid strong, toxic, and expensive oxidants.[1] Indeed, O 2 is nowadays considered as an appealing oxidant for sustainable oxidation chemistry.N ature has developed al arge panel of metalcontaining enzymes to perform selective and efficient oxidation reactions through dioxygen activation.[2] O 2 activation at am etal center generally entails its two-electron reduction to the peroxo state and subsequent OÀOb ond cleavage.I n dinuclear centers,t he second metal ion acts as ar eductant, while in mononuclear active sites,anexternal electron donor is required. This is the case for copper metalloenzymes such as dopamine b-monooxygenase (DbM), peptidylglycine ahydroxylating monooxygenase (PHM), and the recently identified insect tyramine b-monooxygenase (TbM) that are involved in the transformation of various substrates by Cu I /O 2 chemistry.[3] Thec atalytic activity is achieved owing to the presence,i nc lose proximity,o fareducing co-factor that allows aregeneration of the active Cu I species from the final inactive Cu II state (Scheme 1, top). Several bio-inspired mono and dinuclear copper complexes have been reported, but few of them act catalytically in homogeneous conditions. [4] This assessment might originate from the competitive reduction of the active Cu II (O 2 )o xidative species (that is,s uperoxo or peroxo) by the additional sacrificial reductant (Scheme 1, top) that would short-circuit the catalytic cycle.E xploiting our expertise in the development of eco-aware photocatalysts for small molecules activation (such as water [5]

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Cu^I Complexes with N,N′,S,S′ Scorpionate Ligands: Evidence for Dimer−Monomer Equilibria

Cited by 19 publications

References 50 publications

Tuning of the Copper–Thioether Bond in Tetradentate N₃S_(thioether) Ligands; O–O Bond Reductive Cleavage via a [Cu^II₂(μ-1,2-peroxo)]²⁺/[Cu^III₂(μ-oxo)₂]²⁺ Equilibrium

Tuning of the Copper–Thioether Bond in Tetradentate N₃S_(thioether) Ligands; O–O Bond Reductive Cleavage via a [Cu^II₂(μ-1,2-peroxo)]²⁺/[Cu^III₂(μ-oxo)₂]²⁺ Equilibrium

Fluxional rearrangement in congested ruthenium(II) complexes containing pyrimidine- and/or pyridine-based dithioether ligands

A Ruthenium(II)–Copper(II) Dyad for the Photocatalytic Oxygenation of Organic Substrates Mediated by Dioxygen Activation

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CuI Complexes with N,N′,S,S′ Scorpionate Ligands: Evidence for Dimer−Monomer Equilibria

Cited by 19 publications

References 50 publications

Tuning of the Copper–Thioether Bond in Tetradentate N3S(thioether) Ligands; O–O Bond Reductive Cleavage via a [CuII2(μ-1,2-peroxo)]2+/[CuIII2(μ-oxo)2]2+ Equilibrium

Tuning of the Copper–Thioether Bond in Tetradentate N3S(thioether) Ligands; O–O Bond Reductive Cleavage via a [CuII2(μ-1,2-peroxo)]2+/[CuIII2(μ-oxo)2]2+ Equilibrium

Fluxional rearrangement in congested ruthenium(II) complexes containing pyrimidine- and/or pyridine-based dithioether ligands

A Ruthenium(II)–Copper(II) Dyad for the Photocatalytic Oxygenation of Organic Substrates Mediated by Dioxygen Activation

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Cu^I Complexes with N,N′,S,S′ Scorpionate Ligands: Evidence for Dimer−Monomer Equilibria

Tuning of the Copper–Thioether Bond in Tetradentate N₃S_(thioether) Ligands; O–O Bond Reductive Cleavage via a [Cu^II₂(μ-1,2-peroxo)]²⁺/[Cu^III₂(μ-oxo)₂]²⁺ Equilibrium

Tuning of the Copper–Thioether Bond in Tetradentate N₃S_(thioether) Ligands; O–O Bond Reductive Cleavage via a [Cu^II₂(μ-1,2-peroxo)]²⁺/[Cu^III₂(μ-oxo)₂]²⁺ Equilibrium