3029-19-4Relevant academic research and scientific papers
Signaling of hypochlorous acid by selective deprotection of dithiolane
Hwang, Jiyoung,Choi, Myung Gil,Bae, Jihee,Chang, Suk-Kyu
, p. 7011 - 7015 (2011)
The selective signaling of hypochlorous acid by dithiolane-protected pyrene-aldehyde was investigated. Dithiolane derivative of pyrene-aldehyde was efficiently deprotected by hypochlorous acid to its corresponding aldehyde, which resulted in a prominent UV-vis and turn-on type fluorescence signaling. The signaling was not affected by the presence of other common alkali, alkaline earth metal ions, and anions. Interference from Hg2+ ions could be successfully circumvented by using Chelex-100 resin. Dithiolane also provided selectivity toward hypochlorous acid over other commonly used oxidant of hydrogen peroxide.
Photoprocesses in Diphenylpolyenes. 3. Efficiency of Singlet Oxygen Generation from Oxygen Quenching of Polyene Singlets and Triplets
Chattopadhyay, S. K.,Kumar, C. V.,Das, P. K.
, p. 670 - 673 (1985)
The efficiencies of singlet oxygen (1O2*) photogeneration from the oxygen quenching of the excited states (singlet/triplet) of retinal-related polyenals and diphenylpolyenes have been measured in cyclohexane and methanol by 337.1-nm laser flash photolysis.The 1O2* yields are essentially quantitative with all-trans-retinal and its lower and higher homologues as triplet photosensitizers.For all-trans-1,6-diphenyl-1,3,5-hexatriene (DPH) and all-trans-1,8-diphenyl-1,3,5,7-octatetraene (DPO), both singlet and triplet quenching by oxygen contribute to the formation of 1O2*; significant fractions (0.1-0.7) of the oxygen-induced intersystem crossing in these polyene systems take place without energy transfer to oxygen.The triplet-mediated 1O2* yield obtained by steady-state photolysis of all-trans-1,4-diphenyl-1,3-butadiene (DPB) under energy-transfer sensitization by pyrene-1-aldehyde in O2-saturated benzene is less than unity (0.7 +/- 0.1), suggesting possible fractional quenching by oxygen at an orthogonal geometry of DPB triplet (responsible for "nonproduction" of 1O2*).
Shape-selective oxidation of primary alcohols using perruthenate-containing zeolites
Wu, Daniel L.,Wight, Andrea P.,Davis, Mark E.
, p. 758 - 759 (2003)
Potassium perruthenate (KRuO4), a known, effective oxidant for the conversion of primary and secondary alcohols into carbonyl compounds is impregnated into zeolite X and shown to be a shape-selective oxidant using benzyl alcohol (reacted) and pyrenemethanol (not reacted).
OFF-ON fluorescent detection of thymidine nucleotides by a zinc(II)-cyclen complex bearing two diagonal pyrenes
Zeng, Zhanghua,Spiccia, Leone
, p. 12941 - 12944 (2009)
Of a ZnII-cyclen complex bearing two diagonal pyrenes (see picture) has been developed that has a high affinit for thymidine nucleotides, and a much greater enhancement in excimer emission for thymidine triphosphate,-diphosphate and-mono-phosphate than for the other DNA bases and a v of nucleotides.
Fluorescent and electrochemical sensing of polyphosphate nucleotides by ferrocene functionalised with two ZnII(TACN)(pyrene) complexes
Zeng, Zhanghua,Torriero, Angel A. J.,Bond, Alan M.,Spiccia, Leone
, p. 9154 - 9163 (2010)
The [Fc-bis{ZnII(TACN)-(Py)}] complex, comprising two Zn II-(TACN) ligands (Fc = ferrocene; Py = pyrene; TACN = 1,4,7-triazacyclononane) bearing fluorescent pyrene chromophores linked by an electrochemically active ferrocene molecule has been synthesised in high yield through a multistep procedure. In the absence of the polyphosphate guest molecules, very weak excimer emission was observed, indicating that the two pyrenebearing ZnII(TACN) units are arranged in a trans-like configuration with respect to the ferrocene bridging unit. Binding of a variety of polyphosphate anionic guests (PPi and nucleotides diand triphosphate) promotes the interaction between pyrene units and results in an enhancement in excimer emission. Investigations of phosphate binding by31P NMR spectroscopy, fluorescence and electrochemical techniques confirmed a 1:1 stoichiometry for the binding of PPi and nucleotide polyphosphate anions to the bis(ZnII-(TACN)) moiety of [Fc-bis{ZnII-(TACN)(Py)}] and indicated that binding induces a trans to cis configuration rearrangement of the bis(ZnII(TACN)) complexes that is responsible for the enhancement of the pyrene excimer emission. Pyrophosphate was concluded to have the strongest affinity to [Fc-bis{ZnII(TACN)(Py)}] among the anions tested based on a six-fold fluorescence enhancement and 0.1 V negative shift in the potential of the ferrocene/ferrocenium couple. The binding constant for a variety of polyphosphate anions was determined from the change in the intensity of pyrene excimer emission with polyphosphate concentration, measured at 475 nm in CH 3CN/Tris-HCl (1:9) buffer solution (10.0 mm, pH 7.4). These measurements confirmed that pyrophosphate binds more strongly (Kb = (4.45 ± 0.41)×106M-1) than the other nucleotide di-and triphosphates (Kb = 1-50× 105 M-1) tested.
"Shadow" Synthesis, Structure, and Electronic Properties of [2.2](1,6)(1,8)Pyrenophane-1-monoene
Unikela, Kiran Sagar,Tabasi, Zahra A.,Dawe, Louise N.,Zhao, Yuming,Bodwell, Graham J.
, p. 4405 - 4412 (2021)
An unexpected side product of a McMurry reaction was found to be a new [2.2]pyrenophane consisting of two pyrene units with different substitution patterns as well as different types and degrees of distortion from planarity. The new pyrenophane exhibits both monomer and intramolecular excimer fluorescence. Natural bond orbital (NBO) analysis revealed that there is an intramolecular charge-transfer interaction from the more distorted pyrene system to the less distorted one. The origin of the new pyrenophane was traced back to an impurity that was present a full five steps prior to the McMurry reaction from which it was isolated. The pathway to the pyrenophane shadowed that of the main synthetic route.
Redox Noninnocent Azo-Aromatic Pincers and Their Iron Complexes. Isolation, Characterization, and Catalytic Alcohol Oxidation
Sinha, Suman,Das, Siuli,Sikari, Rina,Parua, Seuli,Branda?, Paula,Demeshko, Serhiy,Meyer, Franc,Paul, Nanda D.
, p. 14084 - 14100 (2017)
The new redox-noninnocent azoaromatic pincers 2-(arylazo)-1,10-phenanthroline (L1) and 2,9-bis(phenyldiazo)-1,10-phenanthroline (L2) are reported. The ligand L1 is a tridentate pincer having NNN donor atoms, whereas L2 is tetradentate having two azo-N donors and two N-donor atoms from the 1,10-phenanthroline moiety. Reaction of FeCl2 with L1 or L2 produced the pentacoordinated mixed-ligand Fe(II) complexes FeL1Cl2 (1) and FeL2Cl2 (2), respectively. Homoleptic octahedral Fe(II) complexes, mer-[Fe(L1)2](ClO4)2 [3](ClO4)2 and mer-[Fe(L2)2](ClO4)2 [4](ClO4)2, have been synthesized from the reaction of hydrated Fe(ClO4)2 and L1 or L2. The ligand L2, although having four donor sites available for coordination, binds the iron center in a tridentate fashion with one uncoordinated pendant azo function. Molecular and electronic structures of the isolated complexes have been scrutinized thoroughly by various spectroscopic techniques, single-crystal X-ray crystallography, and density functional theory. Beyond mere characterization, complexes 1 and 2 were successfully used as catalysts for the aerobic oxidation of primary and secondary benzylic alcohols. A wide variety of substituted benzyl alcohols were found to be converted to the corresponding carbonyl compounds in high yields, catalyzed by complex 1. Several control reactions were carried out to understand the mechanism of this alcohol oxidation reactions.
Hg2+ induced hydrolysis of thiazole amine based Schiff base: Colorimetric and fluorogenic chemodosimeter for Hg2+ ions in an aqueous medium
Tekuri, Venkatadri,Sahoo, Suban K.,Trivedi, Darshak R.
, p. 19 - 26 (2019)
Simple pyrene-based chemosensors 1 to 3, were synthesized from pyrene-1-carboxaldehyde and they were characterized using various spectroscopic techniques like UV–Vis, FT-IR, Mass, 1H NMR and 13C NMR. Among synthesized receptors, the receptor 1 shows high selectivity towards Hg2+ ions. Further, the high selectivity of receptor 1 towards Hg2+ ions in the presence of various other interfering metal ions like Ni2+, Zn2+, Mn2+, Co2+, Cu2+, Cr3+, Fe3+, Al3+, Ag+, Fe2+, Cd2+, Mg2+, Pb2+, Ca2+, Na+, K+ was confirmed by UV–Vis and fluorescence methods. The detection limit for Hg2+ ions was found to be 0.270 μM. The chemodosimetric irreversible hydrolysis of the receptor 1 in the presence of Hg2+ was studied by UV/Vis, fluorescence, FT-IR, LC-MS, 1H NMR and theoretical DFT study. Further, the real life applications of receptor 1 for the determination of Hg2+ ions were demonstrated by UV–Vis method.
An Azoaromatic Ligand as Four Electron Four Proton Reservoir: Catalytic Dehydrogenation of Alcohols by Its Zinc(II) Complex
Pramanick, Rajib,Bhattacharjee, Rameswar,Sengupta, Debabrata,Datta, Ayan,Goswami, Sreebrata
, p. 6816 - 6824 (2018)
Electroprotic storage materials, though invaluable in energy-related research, are scanty among non-natural compounds. Herein, we report a zinc(II) complex of the ligand 2,6-bis(phenylazo)pyridine (L), which acts as a multiple electron and proton reservoir during catalytic dehydrogenation of alcohols to aldehydes/ketones. The redox-inactive metal ion Zn(II) serves as an oxophilic Lewis acid, while the ligand behaves as efficient storage of electron and proton. Synthesis, X-ray structure, and spectral characterizations of the catalyst, ZnLCl2 (1a) along with the two hydrogenated complexes of 1a, ZnH2LCl2 (1b), and ZnH4LCl2 (1c) are reported. It has been argued that the reversible azo-hydrazo redox couple of 1a controls aerobic dehydrogenation of alcohols. Hydrogenated complexes are hyper-reactive and quantitatively reduce O2 and para-benzoquinone to H2O2 and para-hydroquinone, respectively. Plausible mechanistic pathways for alcohol oxidation are discussed based on controlled experiments, isotope labeling, and spectral analysis of intermediates.
Deprotonation Induced Ligand Oxidation in a NiII Complex of a Redox Noninnocent N1-(2-Aminophenyl)benzene-1,2-diamine and Its Use in Catalytic Alcohol Oxidation
Sikari, Rina,Sinha, Suman,Jash, Upasona,Das, Siuli,Brandao, Paula,De Bruin, Bas,Paul, Nanda D.
, p. 6114 - 6123 (2016)
Two nickel(II)-complexes, [NiII(H3L)2](ClO4)2 ([1](ClO4)2) and [NiII(HL)2] (2), containing the redox-active tridentate ligand N1-(2-aminophenyl)benzene-1,2-diamine (H3L) have been synthesized. Complex [1](ClO4)2 is octahedral containing two neutral H3L ligands in a facial coordination mode, whereas complex 2 is a singlet diradical species with approximately planar configuration at the tetracoordinate metal atom with two pendant NH2 side arms from each of the coordinated ligands. Both complexes are found to be chemically interconvertible; complex [1]2+ gets converted to complex 2 when exposed to base and oxygen via simultaneous deprotonation and oxidation of the coordinated ligands. Molecular and electronic structures of the isolated complexes are scrutinized thoroughly by various spectroscopic techniques, single crystal X-ray crystallography, and density functional theory. The observed dissociation of a ligand arm upon oxidation of the ligand was exploited to bring about catalytic alcohol oxidation using coordinatively saturated complex [1](ClO4)2 as a catalyst precursor. Both the complexes [1](ClO4)2and 2 were tested for catalytic oxidation of both primary and secondary alcohols.
