82137-72-2Relevant academic research and scientific papers
New Pyrazole- and Benzimidazole-derived Ligand Systems
Nozari, Mohammad,Addison, Anthony W.,Reeves, GorDan T.,Zeller, Matthias,Jasinski, Jerry P.,Kaur, Manpreet,Gilbert, Jayakumar G.,Hamilton, Clifton R.,Popovitch, Jonathan M.,Wolf, Lawrence M.,Crist, Lindsay E.,Bastida, Natalia
, p. 1291 - 1307 (2018)
A series of N-containing heterocyclic compounds have been synthesized using approaches such as the well-known Knorr synthesis, and a facile N-alkylation method. This series of compounds includes pyrazole derivatives, tris(2-benzimidazolylmethyl)amine derivatives, and “pincer” ligands. Characterization methods include 1H NMR, FT-IR, CHN analyses, UV-vis spectroscopy, and fluorimetry, while X-ray crystal structures are reported for most of the compounds. The crystallographic results affirm a 13C NMR method for isomer assignment of substituted pyrazoles.
Design, synthesis, structural, spectral, and redox properties and phenoxazinone synthase activity of tripodal pentacoordinate Mn(ii) complexes with impressive turnover numbers
Giri, Bishnubasu,Karumban, Kalai Selvan,Kumbhakar, Sadananda,Maji, Somnath,Muley, Arabinda
, p. 16601 - 16612 (2021/12/07)
Catechol oxidase (CO) and phenoxazinone synthase (PHS) are two enzymes of immense significance due to their capability to oxidize catechols and o-aminophenols to o-quinones and phenoxazinones, respectively. In this connection two mononuclear manganese complexes with the molecular framework [MnII(Ln)Cl]Cl {L1: tris((1H-benzo[d]imidazol-2-yl)methyl)amine; n = 1 and L2: tris(N-methylbenzimidazol-2-ylmethyl)amine; n = 2} have been designed to be potential catalysts for OAPH (o-aminophenol) oxidation. Both the ligands and their corresponding metal complexes have been successfully synthesized and thoroughly characterized by different spectroscopic and analytical techniques such as FT-IR, 1H NMR, UV-vis spectroscopy, EPR spectroscopy and ESI mass spectroscopy. The molecular structures of [MnII(L1)Cl]Cl (1) and [MnII(L2)Cl]Cl (2) have been revealed by a single-crystal X-ray diffraction study. The spectral properties and redox behaviour of both the complexes were examined. Under ambient conditions, 1 and 2 show excellent phenoxazinone synthase activity as both are very susceptible to oxidize o-aminophenol to phenoxazinone. The kinetic parameters for both complexes have been determined by analyzing the experimental spectroscopic data. The turnover numbers (kcat value) of these two complexes are extremely high, 440 h-1 and 234 h-1 for 1 and 2, respectively. The present report offers a thorough overview of information involving the role of the metal ions and their extent of phenoxazinone synthase mimicking activity. The oxidation of o-aminophenol to 2-amino-3H-phenoxazine-3-one (APX) by catalytic oxidation of oxygen (O2) by the reaction with transition metal complexes has been an important study for the last few decades. The current study evidently showed better performance of our synthesized Mn(ii) complexes than all the predecessors. The plausible mechanism has been reiterated based on the experimental data via ESI-MS spectra and considering the concepts from the previously reported mechanisms involved in the formation of hydrogen peroxide (H2O2) as an intermediate substrate is fairly indicating the involvement of molecular oxygen in the catalytic cycle.
Reverse photoluminescence responses of Ln(iii) complexes to methanol vapor clarify the differentiated energy transfer pathway and potential for methanol detection and encryption
Fan, Ya-Nan,Fu, Peng-Yan,Guo, Jing,Pan, Mei,Su, Cheng-Yong,Yin, Shao-Yun
supporting information, p. 16907 - 16914 (2020/12/30)
Advanced photoluminescent (PL) materials with unique and unclonable photophysical behaviors are important for potential applications in hazardous material detection and optical encryption. We herein present new detecting and encrypting models based on the uncommon reverse photoluminescence response of Eu(iii) and Tb(iii) complexes with isomorphic structures. Upon the stimulus of methanol vapor, the characteristic red emission of Eu(iii) shows an unusual turn on magnification depending on crystal morphologies, manifesting a more sensitive response from the lamellar crystals with not so perfect crystalline forms, while the green emission of Tb(iii) turns down conversely. This clarifies an unprecedent proof for the differentiated energy transfer (ET) pathway, i.e., triplet ET to Eu(iii), while singlet ET to Tb(iii) in lanthanide complexes. Furthermore, patterned taggants can be designed from the interweaving of unary and binary Eu/Tb(iii) complexes, presenting new optical detecting and encrypting models with pixel-selective responding and methanol vapor detecting capacities.
Mononuclear Nonheme High-Spin (S=2) versus Intermediate-Spin (S=1) Iron(IV)–Oxo Complexes in Oxidation Reactions
Bae, Seong Hee,Seo, Mi Sook,Lee, Yong-Min,Cho, Kyung-Bin,Kim, Won-Suk,Nam, Wonwoo
supporting information, p. 8027 - 8031 (2016/09/13)
Mononuclear nonheme high-spin (S=2) iron(IV)–oxo species have been identified as the key intermediates responsible for the C?H bond activation of organic substrates in nonheme iron enzymatic reactions. Herein we report that the C?H bond activation of hydrocarbons by a synthetic mononuclear nonheme high-spin (S=2) iron(IV)–oxo complex occurs through an oxygen non-rebound mechanism, as previously demonstrated in the C?H bond activation by nonheme intermediate (S=1) iron(IV)–oxo complexes. We also report that C?H bond activation is preferred over C=C epoxidation in the oxidation of cyclohexene by the nonheme high-spin (HS) and intermediate-spin (IS) iron(IV)–oxo complexes, whereas the C=C double bond epoxidation becomes a preferred pathway in the oxidation of deuterated cyclohexene by the nonheme HS and IS iron(IV)–oxo complexes. In the epoxidation of styrene derivatives, the HS and IS iron(IV) oxo complexes are found to have similar electrophilic characters.
Synthesis and characterization of benzimidazole-based zinc complexes as structural carbonic anhydrase models and their applications towards CO 2 hydration
Ibrahim, Mohamed M.,Amin, Mahmoud A.,Ichikawa, Kazuhiko
experimental part, p. 191 - 201 (2011/04/14)
The tripod ligand tris(2-benzimidazolylmethyl)amine L1 and its methylated derivative tris(N-methyl-2-benzimidazolylmethyl)amine L2 were used for the preparation of chloro complexes [L1Zn-Cl](PF 6) 1 and [L2Zn-Cl](PF6) 2. These complexes reacted with AgPF6 in aqueous acetone to form the corresponding aqua complexes [L1Zn-OH2](PF6)2 3, [L2Zn(H2O)](PF6)2 4, which were deprotonated by using KOH to form the hydroxide complexes [L1Zn-OH)] (PF6) 5 and [L2Zn-OH)](PF6) 6. 1H NMR titration of the ligands with Zn(II) ions gave detailed information about the structure of the resulting zinc complexes and the evidence for the existence of the zinc-bound hydroxo species. Complex 3 reacted with CO2 gas in the presence of triethylamine to give the bicarbonate complex [L 1Zn-OCO2H)](PF6), which was characterized by IR and 13C NMR spectroscopes. The X-ray structure of [L 1Zn-NCS]2[Zn(NCS)4] 7 as structural carbonic anhydrase inhibitor was determined and adopted slightly distorted tetrahedral ZnN4 coordination geometries with the equatorial positions occupied by three benzimidazole nitrogen atoms and apical position by nitrogen atom from the thiocyanate anion.
Dimeric Copper(II) Compounds with a Tripodal Imidazole-containing Ligand and bridged by Imidazolate, Benzimidazolate, and Benzotriazolate Ions. Crystal and Molecular Structure of μ-(benzotriazolato-N1,N3)-bis(1-methylbenzimidazol-2-ylmethyl)amine-N,N3,N3',N3''>...
Hendriks, Hugo M. J.,Birker, Paul J. M. W. L.,Verschoor, Gerrit C.,Reedijk, Jan
, p. 623 - 632 (2007/10/02)
A series of dimeric copper(II) co-ordination compounds with general formula X3 has been prepared and characterized, where tmbma is the tripodal benzimidazole-containing ligand tris(N-methylbenzimidazol-2-ylmethyl)amine, azolate is the anion of imidazole, benzimidazole, or benzotriazole, and X = NO3(1-), BF4(1-), or ClO4(1-).Variable-temperature magnetic susceptibility measurements indicate antiferromagnetic interactions with J values of -10 to -18 cm-1 (for the benzimidazolate and benzotriazolate compounds) and -28 cm-1 (for the imidazolate compouds).Q-Band and X-Band e.s.r. spectra show typical S = 1 signals; D values calculated from these spectra range from 0.08 to 0.13 cm-1.The crystal and molecular structure of the title compound has been determined by single-crystal X-ray diffraction.The compound crystallizes in the space group C2/c, with a = 16.880(2), b = 26.011(1), c = 14.686(1) Angstroem, β = 100.585(7)deg, and Z = 4.The structure was solved by heavy-atom methods and refined using least-squares techniques to a residual R of 0.050 for 3 327 reflections with l > 2?(l).The structure consists of dimeric cations, having C2 symmetry, and disordered nitrate anions; the co-ordination geometry around the copper ions can be described as distorted trigonal bipyramidal with three equatorial benzimidazole nitrogen atoms, one axial amine nitrogen atom, and the benzotriazolate ion bringing from an axial position on one copper ion to an axial position on the other copper ion, resulting in a Cu...Cu distance of 5.536(2) Angstroem.
