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).
Polyoxometalate-based supramolecular porous frameworks with dual-active centers towards highly efficient synthesis of functionalized: P -benzoquinones
An, Haiyan,Chang, Shenzhen,Chen, Yanhong,Huang, Yaohui,Luo, Huiyun,Zhu, Qingshan
, p. 8591 - 8603 (2021/11/17)
Selective oxidation of substituted phenols is an ideal method for preparing functionalized p-benzoquinones (p-BQs), which serve as versatile raw materials for the synthesis of a variety of biologically active compounds. Herein, two new polyoxometalate-based supramolecular porous frameworks, K3(H2O)4[Cu(tza)2(H2O)]2[Cu(Htza)2(H2O)2][BW12O40]·6H2O (1) and H3K3(H2O)3[Cu(Htza)2(H2O)]3[SiW12O44]·14H2O (2) (Htza = tetrazol-1-ylacetic acid), were synthesized and structurally characterized by elemental analysis, infrared spectroscopy, thermal analysis, UV-vis diffuse reflectance spectroscopy, and single-crystal X-ray and powder diffraction. The single-crystal X-ray diffraction analysis indicates that both compounds possess unique petal-like twelve-nucleated Cu-organic units composed of triangular and hexagonal metal-organic loops. In 1, the Cu-organic units are isolated and [BW12O40]5- polyoxoanions are sandwiched between staggered adjacent triangular channels in the structure. However in 2, the Cu-organic units extend into a two-dimensional layered structure, and the [SiW12O44]12- polyoxoanions occupy the larger hexagonal channels in the stacked structure. Both compounds as heterogeneous catalysts can catalyze the selective oxidation of substituted phenols to high value-added p-BQs under mild conditions (60 °C) with TBHP as the oxidant, particularly in the oxidation of 2,3,6-trimethylphenol to 2,3,5-trimethyl-p-benzoquinone (TMBQ, key intermediate in vitamin E production). Within 8-10 min, the yield of TMBQ is close to 100%, and oxidant utilization efficiency is up to 94.2% for 1 and 90.9% for 2. The turnover frequencies of 1 and 2 are as high as 5000 and 4000 h-1, respectively. No obvious decrease in the yield of TMBQ was observed after five cycles, which indicates the excellent sustainability of both compounds. Our study of the catalytic mechanism suggests that there is a two-site synergetic effect: (i) the copper ion acts as the catalytic site of the homolytic radical pathway; and (ii) the polyoxoanion acts as the active center of the heterolytic oxygen atom transfer pathway. This journal is
Oxidative Dearomatization of Phenols and Polycyclic Aromatics with Hydrogen Peroxide Triggered by Heterogeneous Sulfonic Acids
Pancrazzi, Francesco,Maestri, Giovanni,Maggi, Raimondo,Viscardi, Rosanna
supporting information, p. 5407 - 5414 (2021/10/25)
We report herein a method for the oxidative dearomatization of phenols and bare polycyclic arenes into the corresponding quinoid derivatives using hydrogen peroxide. The reaction is catalyzed by sulfonic acids and best results were achieved using heterogenized species. The best results using phenols were achieved using a hybrid material, namely a perfluorinated polymer functionalized with sulfonic acid groups supported on silica. The dearomatization of polycyclic aromatic hydrocarbons performed better using the polymeric acid catalyst. These methods operate under mild conditions, using mild and benign oxidants and thus minimizing the formation of waste.
