Xi:Irritant;719-22-2Relevant articles and documents
A 1:1 copper-dioxygen adduct is an end-on bound superoxo copper(II) complex which undergoes oxygenation reactions with phenols
Maiti, Debabrata,Fry, H. Christopher,Woertink, Julia S.,Vance, Michael A.,Solomon, Edward I.,Karlin, Kenneth D.
, p. 264 - 265 (2007)
Employing a strongly electron-donating tripodal tetradentate ligand along with a reaction strategy designed to suppress binuclear peroxo complex formation, an end-on bound superoxo-copper(II) complex [CuII(NMe2-TMPA)(O2-)]+ (1) has been generated in solution [UV-vis (THF, -85 °C): λmax = 418 nm (ε, 4300 M-1 cm-1), 615 nm (ε, 1100), 767 nm (ε, 840)]. Resonance Raman spectroscopy employing isotopically substituted dioxygen (including mixed isotope 16/18O2) proves the end-on superoxo CuII(O2-) structural formulation, ν(O-O) = 1121 cm-1; ν(Cu-O) = 472 cm-1. The first demonstration of CuII(O2-) oxidative reactivity with exogenous substrates, likely involving H-atom abstraction chemistry, comes with the finding that 1 effects the oxygenation and hydroperoxylation of substituted phenols. Copyright
The synthesis, characterization, DNA/protein interaction, molecular docking and catecholase activity of two Co(II) complexes constructed from the aroylhydrazone ligand
Li, Yun,Li, Yueqin,Liu, Xiaohui,Yang, Yong,Lin, Dong,Gao, Qinwei
, (2020)
Two Co(II) complexes, Co(BBH)phenMeCN (1) and Co(BSH)phenMeCN (2) (HBBH = benzophenone benzoyl hydrazone, HBSH = benzophenone salicylylhydrazone ligand and phen = 1,10-phenanthroline) were prepared and characterized by single X-ray crystallography. The investigation of the complexes binding with herring sperm DNA (HS-DNA) revealed that stronger binding interaction exists between the complexes and HS-DNA compared to the corresponding free ligands. And both complexes can bind to DNA through intercalation of the phenyl rings between adjacent base pairs in the double helix. Meanwhile, bovine serum albumin (BSA) binding studies reveal the complexes can effectively interact with BSA and change the secondary structure of BSA. Superoxide dismutase (SOD) mimic activity of the complexes was investigated and the results showed that complex 2 showed a stronger radical scavenging potency against O2 .- radical with an IC50 value of 16.10 μM. The catecholase-like activity of both complexes has been investigated with 3,5-di-tert-butylcatechol (3,5-DTBC) as the substrate in methanol solution under completely aerobic conditions. The catalytic reaction follows Michaelis-Menten enzymatic reaction kinetics with turnover numbers (kcat) of 34.14 h?1 and 30.36 h?1 for complex 1 and complex 2, respectively.
Insight into the crystallization process: Relationships between crystal structures and properties of copper(ii) coordination polymers containing dimethylbis(4-pyridyl)silane
Moon, So Yun,Noh, Tae Hwan,Jung, Ok-Sang
, p. 3854 - 3861 (2013)
A systematic investigation into the favorable reaction conditions for construction of copper(ii) coordination polymers was carried out. Various reactions of copper(ii) bromide with dimethylbis(4-pyridyl)silane (L) produce two kinds of skeletal structures: the 1D loop-chain and the square-tubular helix. The fast-formation condition affords the 1D loop-chain, whereas the slow-formation condition yields the helical structure. The formation of significant condition-dependent structures can be partially attributed to the nature of the bromide anion and angle strain around the copper(ii) cation. The relationships between structures and physicochemical properties such as anion exchangeability, catalytic oxidation of 3,5-di-tert-butylcatechol, and thermal properties are discussed in these pages.
A N3S(thioether)-ligated CuII-superoxo with enhanced reactivity
Kim, Sunghee,Lee, Jung Yoon,Cowley, Ryan E.,Ginsbach, Jake W.,Siegler, Maxime A.,Solomon, Edward I.,Karlin, Kenneth D.
, p. 2796 - 2799 (2015)
Previous efforts to synthesize a cupric superoxide complex possessing a thioether donor have resulted in the formation of an end-on trans-peroxo-dicopper(II) species, [{(Ligand)CuII}2(μ-1,2-O22-)]2+. Redesign/modification of previous N3S tetradentate ligands has now allowed for the stabilization of the monomeric, superoxide product possessing a S(thioether) ligation, [(DMAN3S)CuII(O2?-)]+ (2S), as characterized by UV-vis and resonance Raman spectroscopies. This complex mimics the putative CuII(O2?-) active species of the copper monooxygenase PHM and exhibits enhanced reactivity toward both O-H and C-H substrates in comparison to close analogues [(L)CuII(O2?-)]+, where L contains only nitrogen donor atoms. Also, comparisons of [(L)CuII/I]n+ compound reduction potentials (L = various N4 vs DMAN3S ligands) provide evidence that DMAN3S is a weaker donor to copper ion than is found for any N4 ligand-complex.
Liquid Phase Oxidation of 2,6-Di-t-butylphenol by Molecular Oxygen Using Magnesium Oxide Catalysts Modified with Metal Ion
Kurokawa, Hideki,Ueda, Wataru,Morikawa, Yutaka,Moro-Oka, Yoshihiko,Ikawa, Tsuneo
, p. 1919 - 1920 (1987)
Mn(II), Co(II), Cu(II), or Fe(III) ion containing magnesium oxides catalyzed oxidation of 2,6-di-t-butylphenol to quinones by molecular oxygen. 98percent Yield to 1,1'-bis(4-oxo-3,5-di-t-butylcyclohexadienylidene) was obtained with 16.7 wtpercent Mn ion containing magnesium oxide catalyst.
Dioxygen Adducts of Cobalt(II) Complexes of 6,6'-Bis(p-substituted benzoylamino)-2,2'-bipyridines and Their Cytalytic Activities in Oxygenation of 2,6-Di-tert-butylphenol
Araki, Koji,Kuboki, Takashi,Otohata, Makihiro,Kishimoto, Nobuyuki,Yamada, Masaki,Shiraishi, Shinsaku
, p. 3647 - 3652 (1993)
The oxygen affinities and properties of oxygen adducts of complexes has been studied by cyclic voltammetry and IR, electronic and ESR spectroscopy.The complexes exhibited oxygen-binding ability in the presence of an appropriate axial base ligand (B), and the oxygen adducts were of the end-on bonded CoIII(O2(1-)) type (CoL(B)(O2)>.More complete electron transfer from the metal centre to the oxygen was indicated compared to that with .Electron-donating substituents gave higher concentrations of the oxygen adducts.The superior catalytic activity of these complexes, especially the Me- and But-substitued derivatives, in the oxygenation of 2,6-di-tert-butylphenol to the corresponding quinone is interpreted in terms of the reactivity of the co-ordinated oxygen and the oxygen affinity of the complexes.
Dinuclear mixed-valence CoIIICoII complexes derived from a macrocyclic ligand: Unique example of a CoIIICoII complex showing catecholase activity
Majumder, Samit,Mondal, Suraj,Lemoine, Pascale,Mohanta, Sasankasekhar
, p. 4561 - 4569 (2013)
The work in this paper presents the syntheses, characterization, catecholase activity, and electrospray ionization mass spectroscopic (ESI-MS positive) study of three mixed-valence dinuclear CoIIICoII complexes of composition [CoIIICoIIL(N3) 3]·CH3CN (1), [CoIIICo IIL(OCN)3]·CH3CN (2), and [Co IIICoIIL(μ-CH3COO)2](ClO 4) (3), derived from a tetraimino diphenolate macrocyclic ligand H2L, obtained on [2 + 2] condensation of 4-ethyl-2,6-diformylphenol and 2,2′-dimethyl-1,3-diaminopropane. While 1 and 2 are diphenoxo-bridged, 3 is a heterobridged bis(μ-phenoxo)bis(μ-acetate) system. Utilizing 3,5-di-tert-butyl catechol (3,5-DTBCH2) as the substrate, the catecholase activity of all the three complexes has been checked in methanol/acetonitrile/N,N-dimethyl formamide. While 2 and 3 are inactive, complex 1 shows catecholase activity with turnover numbers of 482.16 h -1 and 45.38 h-1 in acetonitrile and methanol, respectively. Electrospray ionization mass (ESI-MS positive) spectra of complexes 1-3 have been recorded in acetonitrile solutions and the positive ions have been well characterized. The ESI-MS positive spectrum of complex 1 in the presence of 3,5-DTBCH2 has also been recorded and, interestingly, two positive ions [CoIIICoIIL(N3) 2(3,5-DTBCH-)H]+ and [CoIICo IIL(μ-3,5-DTBCH2-)Na]+ have been identified. The Royal Society of Chemistry 2013.
Ogura,Matsuura
, p. 3187,3191,3192 (1970)
A multifunctional heterogeneous catalyst: Titanium-containing mesoporous silica material encapsulating magnetic iron oxide nanoparticles
Mori, Kohsuke,Kondo, Yuichi,Morimoto, Shotaro,Yamashita, Hiromi
, p. 1068 - 1069 (2007)
Magnetic iron oxide nanoparticles coated with mesoporous silica involving single-site titanium oxide moiety have been first developed by adopting a two-step coating method. The catalytic performance and magnetically separable ability were demonstrated in the oxidation of 2,6-di-tert-butylphenol using hydrogen peroxide. Copyright
DNA/protein binding, cytotoxicity and catecholase activity studies of a piperazinyl moiety ligand based nickel(II) complex
Mistri, Soumen,Puschmann, Horst,Manna, Subal Chandra
, p. 155 - 163 (2016)
The Ni(II) complex, {[Ni(HL)(SCN)2(H2O)]·2(DMF)} (1) [HL = 6-methoxy-2-{[2-(1-piperazinyl)ethylimino]methyl}phenol], was synthesized and characterized by X-ray crystal structure analysis and spectroscopic methods. The crystal structure of complex 1 reveals a distorted octahedral coordination geometry around the nickel centre which forms a supramolecular assembly through hydrogen bonds. The interaction of complex 1 with the calf thymus DNA (CT-DNA) was investigated using electronic absorption and fluorescence spectroscopic methods. The results show that complex 1 has binding affinity to CT-DNA in the order of 6.06 × 105 M-1. The interactions of complex 1 with bovine serum albumin (BSA) and human serum albumin (HSA) were also studied using electronic absorption and fluorescence spectroscopic techniques and the analysis show that interaction of complex 1 with BSA/HSA occur mainly with ground state association process. The number of binding sites and binding constant were calculated using double logarithm regression equation. Anticancer activity of 1 in human breast (MCF7) cancer cell lines reveals dose dependent suppression of cell viability with IC50 value 64 ± 3.7 μM. Catecholase activity of 1 has been investigated in methanol medium using 3,5-di-tert-butylcatechol (3,5-DTBC) as model substrate and the result shows that 1 is active for catalyzing aerobic oxidation of 3,5-DTBC to 3,5-di-tert-butylbenzoquinone (3,5-DTBQ).
Organophotocatalytic Aerobic Oxygenation of Phenols in a Visible-Light Continuous-Flow Photoreactor
Wellauer, Jo?l,Miladinov, Dragan,Buchholz, Thomas,Schütz, Jan,Stemmler, René T.,Medlock, Jonathan A.,Bonrath, Werner,Sparr, Christof
supporting information, p. 9748 - 9752 (2021/05/27)
A mild photocatalytic phenol oxygenation enabled by a continuous-flow photoreactor using visible light and pressurized air is described herein. Products for wide-ranging applications, including the synthesis of vitamins, were obtained in high yields by precisely controlling principal process parameters. The reactor design permits low organophotocatalyst loadings to generate singlet oxygen. It is anticipated that the efficient aerobic phenol oxygenation to benzoquinones and p-quinols contributes to sustainable synthesis.
Sterically Stabilized End-On Superoxocopper(II) Complexes and Mechanistic Insights into Their Reactivity with O-H, N-H, and C-H Substrates
Debnath, Suman,England, Jason,Kr?mer, Tobias,Laxmi, Shoba,Quek, Sebastian Y.,Van Gastel, Maurice
supporting information, p. 19731 - 19747 (2021/11/30)
Instability of end-on superoxocopper(II) complexes, with respect to conversion to peroxo-bridged dicopper(II) complexes, has largely constrained their study to very low temperatures. This limits their kinetic capacity to oxidize substrates. In response, we have developed a series of bulky ligands, Ar3-TMPA (Ar = tpb, dpb, dtbpb), and used them to support copper(I) complexes that react with O2 to yield [CuII(?1-O2?-)(Ar3-TMPA)]+ species, which are stable against dimerization at all temperatures. Binding of O2 saturates at subambient temperatures and can be reversed by warming. The onset of oxygenation for the Ar = tpb and dpb systems is observed at 25 °C, and all three [CuII(?1-O2?-)(Ar3-TMPA)]+ complexes are stable against self-decay at temperatures of ≤-20 °C. This provides a wide temperature window for study of these complexes, which was exploited by performing extensive reaction kinetics measurements for [CuII(?1-O2?-)(tpb3-TMPA)]+ using a broad range of O-H, N-H, and C-H bond substrates. This includes correlation of second order rate constants (k2) versus oxidation potentials (Eox) for a range of phenols, construction of Eyring plots, and temperature-dependent kinetic isotope effect (KIE) measurements. The data obtained indicate that reaction with all substrates proceeds via H atom transfer (HAT), reaction with the phenols proceeds with significant charge transfer, and full tunneling of both H and D atoms occurs in the case of 1,2-diphenylhydrazine and 4-methoxy-2,6-di-tert-butylphenol. Oxidation of C-H bonds proved to be kinetically challenging, and whereas [CuII(?1-O2?-)(tpb3-TMPA)]+ can oxidize moderately strong O-H and N-H bonds, it is only able to oxidize very weak C-H bonds.
