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1.
Cherkasov VK Abakumov GA Grunova EV Poddel'sky AI Fukin GK Baranov EV Kurskii YV Abakumova LG 《Chemistry (Weinheim an der Bergstrasse, Germany)》2006,12(14):3916-3927
Novel neutral antimony(V) complexes were isolated as crystalline materials and characterized by IR and NMR spectroscopy: o-amidophenolate complexes [4,6-di-tert-butyl-N-(2,6-dimethylphenyl)-o-amidophenolato]triphenylantimony(V) (Ph3Sb[AP-Me], 1) and [4,6-di-tert-butyl-N-(2,6-diisopropylphenyl)-o-amidophenolato]triphenylantimony(v) (Ph3Sb[AP-iPr], 2); catecholate complexes (3,6-di-tert-butyl-4-methoxycatecholato)triphenylantimony(V) (Ph3Sb[(MeO)Cat], 3), its methanol solvate 3CH3OH (4); (3,6-di-tert-butyl-4,5-di-methoxycatecholato)triphenylantimony(V) (Ph3Sb[(MeO)2Cat], 5) and its acetonitrile solvate 5CH3CN (6). Complexes 1-7 were synthesized by oxidative addition of the corresponding o-iminobenzoquinones or o-benzoquinones to Ph3Sb. In the case of the phenanthrene-9,10-diolate (PhenCat) ligand, two different complexes were isolated: Ph3Sb[PhenCat] (7) and [Ph4Sb]+[Ph2Sb(PhenCat)2]- (8). Complexes 7 and 8 were found to be in equilibrium in solution. Molecular structures of 2, 4, 6, and 8 were determined by X-ray crystallography. Complexes 1-7 reversibly bind molecular oxygen to yield Ph3Sb[L-Me]O2 (9), Ph3Sb[L-iPr]O2 (10), Ph3Sb[(MeO)L']O2 (11), Ph3Sb[(MeO)2L']O2 (12) and Ph3Sb[PhenL']O2 (13), which contain five-membered trioxastibolane species (where L is the O,O',N-coordinated derivative of a 1-hydroperoxy-6-(N-aryl)-iminocyclohexa-2,4-dienol, and L' the O,O',O'-coordinated derivative of 6-hydroperoxy-6-hydroxycyclohexa-2,4-dienone). Complexes 9-13 were characterized by IR and 1H NMR spectroscopy and X-ray crystallography. 相似文献
2.
Andrey I. Poddel’sky Ivan V. Smolyaninov Nadezhda T. Berberova Gleb A. Abakumov 《Journal of organometallic chemistry》2010,695(4):530-522
Triphenylantimony(III) and triethylantimony(III) readily react with 4,5-(1,1,4,4-tetramethyl-butane-1,4-diyl)-o-benzoquinone to form catecholato complexes R3Sb(4,5-Cat) (R = Ph (1), Et (2); 4,5-Cat is dianionic 4,5-(1,1,4,4-tetramethyl-butane-1,4-diyl)-catecholate). In polar solvents (CHCl3, acetone) complex 1 transforms easily to ionic complex compound [Ph4Sb]+[Ph2Sb(4,5-Cat)2]− (3) with diphenyl-bis-[4,5-(1,1,4,4-tetramethyl-butane-1,4-diyl)-catecholato]antimony(V) complex anion. Complexes were characterized by IR, 1H, 13C NMR spectroscopy, cyclic voltammometry. Molecular structure of 3·CHCl3 was confirmed by X-ray analysis. Cyclic voltammometry of 1 and 3 shows that both complexes undergo reversible one-electron oxidation to quite stable paramagnetic o-semiquinonato species [Ph3Sb(4,5-SQ)]+ and [Ph2Sb(4,5-SQ)(4,5-Cat)] (0.75 and 0.49 V in CH2Cl2 vs. Ag/AgCl/KCl, respectively). 相似文献
3.
I. V. Smol’yaninov A. I. Poddel’skii S. A. Smol’yaninova N. O. Movchan 《Russian Journal of General Chemistry》2014,84(9):1761-1766
Triarylantimony(V) catecholate complexes were synthesized by the oxidative addition of 3,6-di-tert-butyl-4,5-dimethoxy-o-benzoquinone to triarylstibines. The electrochemical properties and antiradical activity of the synthesized compounds were studied. According to cyclic viltammetry data, the complexes are oxidized via two consecutive quasi-reversible stages. Introduction of halogen atoms in para-position of phenyl groups at Sb(V) causes anodic shifts of the oxidation potentials and enhances stability of the mono- and dicationic forms of the compounds, which form in the course of electrochemical transformations. Triarylantimony(V) catecholate complexes exhibit appreciable antiradical activity in the auto-oxidation of oleic acid. In was found that the inhibitory activity of the complexes depends on their redox potential. 相似文献
4.
Georgy K. Fukin Ilia A. Guzei Evgenii V. Baranov Georgy A. Domrachev 《Structural chemistry》2009,20(4):643-654
The ligand solid angle approach has been successfully applied to the analysis of the catecholate complexes of Sb(III) and
Sb(V). The Sb(III) complexes possess an electron lone pair that influences their molecular structure but does not behave as
a classic “ligand” when intermolecular interactions are concerned. The Sb(III) complexes in solid state form numerous intermolecular
interactions that effectively increase metal shielding, and herein we analyze the effects of the lone pair of electrons on
the complex coordination geometry. In the five-coordinate R3CatSb(V) complexes (Cat = catecholate ligand, R = Ph, Me, Cl) the metal is shielded by 87(3)% and multiple intermolecular
contacts are observed. The central metal in the six-coordinate antimony(V) complexes R3CatSb(V) · L is shielded to the extent of 89(2)% and no strong attractive intermolecular interactions are detected in solid
state. Thus, the metal shielding in excess of 85% is required to prevent complex dimerization or additional ligation of the
central atom by a nucleophile. 相似文献
5.
Piskunov AV Maleeva AV Fukin GK Baranov EV Bogomyakov AS Cherkasov VK Abakumov GA 《Dalton transactions (Cambridge, England : 2003)》2011,40(3):718-725
The interaction of 3,6-di-tert-butyl-o-benzoquinone (3,6-Q) with indium in toluene leads to the tris-o-semiquinolate derivative (3,6-SQ)(3)In (3,6-SQ - radical-anion of 3,6-Q). According to single-crystal X-ray diffraction analysis, this complex has a trigonal prismatic structure. Magnetic measurements revealed that the exchange interactions between odd electrons of the paramagnetic ligands in (3,6-SQ)(3)In are antiferromagnetic in character. The treatment of (3,6-SQ)(3)In with 2,2'-dipyridyl (Dipy) causes the displacement of one o-quinone ligand and the formation of the (3,6-SQ)In(Dipy)(3,6-Cat) (3,6-Cat - dianion of 3,6-Q) derivative containing mixed charged o-quinoid ligands. The reaction of InI with (3,6-SQ)K in THF solution is accompanied by a redox process and the potassium-indium(iii) catecholate derivative was obtained as a result. The oxidation of InI with 3,6-Q in THF produces the dimeric In(iii) iodo-catecholate complex [(3,6-Cat)(2)In·2THF]InI(2). The same derivative can be synthesized by the interaction of indium metal with a mixture of I(2) and 3,6-Q. 相似文献
6.
Vladimir K. Cherkasov Georgy K. Fukin Yury A. Kurskii Ludmila G. Abakumova Gleb A. Abakumov 《Journal of organometallic chemistry》2005,690(5):1273-1281
New catecholate Sb(V) complexes triphenyl(3,6-di-tert-butylcatecholato)antimony(V) Ph3Sb(3,6-DBCat) (1) and triphenyl(perchloroxanthrenecatecholato)antimony(V) Ph3Sb(OXCatCl) (2) were synthesized by the oxidative addition reaction of corresponding o-quinones (3,6-di-tert-butyl-o-benzoquinone and perchloroxanthrenequinone-2,3) with triphenylantimony. Catecholates 1 and 2 can alternatively be synthesized by reacting the appropriate thallium catecholate with triphenylantimony dichloride. The oxidative addition reaction of an equimolar ratio of 4,4′-di-(3-methyl-6-tert-butyl-o-benzoquinone) and triphenylantimony yielded 4-(2-methyl-5-tert-butyl-cyclohexadien-1,5-dion-3,4-yl)-(3-methyl-6-tert-butyl-catecholato)triphenylantimony(V) Ph3Sb(Cat-Q) (3); in the case of a 1:2 molar ratio, complex 4,4′-di-[(3-methyl-6-tert-butyl-catecholato)triphenylantimony(V)] Ph3Sb(Cat-Cat)SbPh3 (4) resulted. Complexes 1-4 were characterized by IR- and 1H NMR spectroscopy. Molecular structures of 1, 2 and 4 were determined by X-ray crystallography to be a distorted tetragonal-pyramidal. 相似文献
7.
A. V. Piskunov A. V. Maleeva I. N. Meshcheryakova G. K. Fukin 《Russian Journal of Coordination Chemistry》2013,39(3):245-256
Indium catecholate complexes 3,6-CatInR (3,6-Cat is the 3,6-di-tert-butyl-o-benzoquinone dianion (3,6-Q), R = Me (I) and Et (II)) are synthesized by the exchange reaction between RInI2 and thallium catecholate 3,6-CatTl2. Compounds I and II are trimeric in both the solution and crystalline state. The oxidation of compound I and earlier described complex [3,6-CatInI(THF)]2 (THF is tetrahydrofuran) by various substrates (iodine, 3,6-Q, and tetramethylthiuram disulfide) is studied. Different indium(III) o-semiquinone complexes are the reaction products, depending on the reaction conditions. 相似文献
8.
Poddel’skii A. I. Okhlopkova L. S. Meshcheryakova I. N. Druzhkov N. O. Smolyaninov I. V. Fukin G. K. 《Russian Journal of Coordination Chemistry》2019,45(2):133-141
Russian Journal of Coordination Chemistry - New catecholate complexes of triphenylantimony(V), (Etgly-3,6-DBCat)SbPh3 (I), (Propgly-3,6-DBCat)SbPh3 (II), and (Cat-3,6-DBCat)SbPh3 (III), based on... 相似文献
9.
Oliveira LG Silva MM Paula FC Pereira-Maia EC Donnici CL Simone CA Frézard F Silva EN Demicheli C 《Molecules (Basel, Switzerland)》2011,16(12):10314-10323
Antimony(V) and bismuth(V) complexes of lapachol have been synthesized by the reaction of Ph?SbCl? or Ph?BiCl? with lapachol (Lp) and characterized by several physicochemical techniques such as IR, and NMR spectroscopy and X-ray crystallography. The compounds contain six-coordinated antimony and bismuth atoms. The antimony(V) complex is a monomeric derivative, (Lp)(Ph?Sb)OH, and the bismuth(V) complex is a dinuclear compound bridged by an oxygen atom, (Lp)?(Ph?Bi)?O. Both compounds inhibited the growth of a chronic myelogenous leukemia cell line and the complex of Bi(V) was about five times more active than free lapachol. This work provides a rare example of an organo-Bi(V) complex showing significant cytotoxic activity. 相似文献
10.
Lansky DE Mandimutsira B Ramdhanie B Clausén M Penner-Hahn J Zvyagin SA Telser J Krzystek J Zhan R Ou Z Kadish KM Zakharov L Rheingold AL Goldberg DP 《Inorganic chemistry》2005,44(13):4485-4498
The structural and physicochemical properties of the manganese-corrolazine (Cz) complexes (TBP8Cz)Mn(V)O (1) and (TBP8Cz)Mn(III) (2) (TBP = p-tert-butylphenyl) have been determined. Recrystallization of 2 from toluene/MeOH resulted in the crystal structure of (TBP8Cz)Mn(III)(CH3OH) (2 x MeOH). The packing diagram of 2 x MeOH reveals hydrogen bonds between MeOH axial ligands and meso N atoms of adjacent molecules. Solution binding studies of 2 with different axial ligands (Cl-, Et3PO, and Ph3PO) reveal strong binding, corroborating the preference of the Mn(III) ion for a five-coordinate environment. High-frequency and field electron paramagnetic resonance (HFEPR) spectroscopy of solid 2 x MeOH shows that 2 x MeOH is best described as a high-spin (S = 2) Mn(III) complex with zero-field splitting parameters typical of corroles. Structural information on 1 was obtained through an X-ray absorption near-edge structure (XANES)/extended X-ray absorption fine structure (EXAFS) study and compared to XANES/EXAFS data for 2 x MeOH. The XANES data for 1 shows an intense pre-edge transition characteristic of a high-valent metal-oxo species, and a best fit of the EXAFS data gives a short Mn-O bond distance of 1.56 A, confirming the structure of the metal-oxo unit in 1. Detailed spectroelectrochemical studies of 1 and 2 were performed revealing multiple reversible redox processes for both complexes, including a relatively low potential for the Mn(V) --> Mn(IV) process in 1 (near 0.0 V vs saturated calomel reference electrode). Chemical reduction of 1 results in the formation of a Mn(III)Mn(IV)(mu-O) dimer as characterized by electron paramagnetic resonance spectroscopy. 相似文献
11.
The molecular structures and physicochemical properties of diruthenium complexes with ligand-unsupported Ru-Ru bonds, generally formulated as [A2{Ru2(DTBCat)4}] (DTB = 3,5- or 3,6-di-tert-butyl; Cat(2-) = catecholate), were studied in detail by changing the countercations. First, the binding structures of the cations in a family of [{A(DME)n}2{Ru2(3,5-DTBCat)4}] (n = 2 for A+ = Li+ and Na+ and n = 1 for A+ = K+ and Rb+) were systematically examined to reveal the effects of the cations on the molecular structures and electrochemical properties. Second, the complex (n-Bu4N)2[Ru2(3,6-DTBCat)4] with a cation-free structure was synthesized using tetra-n-butylammonium cations. The complex clearly demonstrates first that the ligand-unsupported Ru-Ru bonds are essentially stabilized by the dianionic nature of the catecholate derivatives without any other bridging or supporting species. In contrast, the redox potentials and absorption spectra of the complexes can sensitively respond to the countercations depending upon the polarity of the solvents. 相似文献
12.
Andrey I. Poddel’sky Ivan V. Smolyaninov Georgy K. Fukin Vladimir K. Cherkasov 《Journal of organometallic chemistry》2010,695(8):1215-8281
Novel functionalized triphenylantimony(V) catecholates - Ph3Sb[4-O(CH2CH2)2N-3,6-DBCat] (1), Ph3Sb[4-PhN(CH2CH2)2N-3,6-DBCat] (2), Ph3Sb[4-Ph2CHN(CH2CH2)2N-3,6-DBCat] (3), Ph3Sb[4,5-Piperaz-3,6-DBCat] (4) and binuclear bis-catecholate Ph3Sb[3,6-DBCat-4-N(CH2CH2)2N-4-3,6-DBCat]SbPh3 (5) were synthesized by the oxidative addition reaction of corresponding o-quinones with triphenylantimony. The [4-O(CH2CH2)2N-3,6-DBCat]2−, [4-PhN(CH2CH2)2N-3,6-DBCat]2−, [4-Ph2CHN(CH2CH2)2N-3,6-DBCat]2− and [4,5-Piperaz-3,6-DBCat]2− are 4-(morpholin-1-yl)-, 4-(4-phenyl-piperazin-1-yl)-, 4-(4-dephenylmethyl-piperazin-1-yl)-, and 4,5-(piperazin-1,4-diyl)-3,6-di-tert-butyl-catecholate dianionic ligands, correspondingly. Complexes 1-5 were characterized in details by IR-, 1H and 13C NMR spectroscopy and cyclic voltammometry. Molecular structure of 4·CH3OH was determined by X-ray crystallography to be a distorted tetragonal-pyramidal. The NMR spectroscopic and electrochemical investigations of complexes in the presence of air reveal the reactions of complexes with dioxygen leading to the formation of spiroendoperoxides of 1,2,4,3-trioxastibolane type in a NMR yield of 25-37%. 相似文献
13.
The influence of triphenylantimony(V) catecholate and its spiroendoperoxide on lipid peroxidation 下载免费PDF全文
Ivan V. Smolyaninov Natalia A. Antonova Andrey I. Poddel'sky Susanna A. Smolyaninova Viktoria P. Osipova Svetlana A. Luzhnova Nadezhda T. Berberova Yuri T. Pimenov 《应用有机金属化学》2014,28(4):274-279
The effects of triphenylantimony(V) catecholate Ph3Sb(Cat) (1) and its spiroendoperoxide Ph3Sb(L‐O2) (2) (Cat = 3,6‐di‐tert‐butyl‐4,5‐dimethoxycatecholate) on lipid peroxidation (LP) in vitro and in vivo were examined in BALB/c line mice. A comparative study of the impact of compounds 1 and 2 on LP under similar conditions was made by measuring the formation of thiobarbituric acid reactive substances (TBARS). The anti‐ or pro‐oxidant action of complexes 1 and 2 may be caused by the different redox level of the ligand acting as radical scavenger and/or by the bound molecular oxygen promoting the oxidation process. Biological experiments (in vitro and in vivo) were performed using mouse tissue homogenates. Decreasing TBARS concentration was observed in all examined tissues and blood serum (in vitro as well as in vivo) for catecholate 1. These results indicate inhibition of LP in the presence of complex 1. In contrast to 1, spiroendoperoxide 2 increases the level of TBARS in tissue homogenates. Minor fluctuations of TBARS concentration in erythrocytes and in blood serum indicate the absence of an obvious anti/pro‐oxidant influence of 2 on the LP process in vivo. The role of catecholate fragment was found to be essential in explaining antioxidant properties. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
14.
I. V. Smolyaninov A. I. Poddel’skii N. A. Antonova S. A. Smolyaninova N. T. Berberova 《Russian Journal of Coordination Chemistry》2013,39(2):165-174
The antiradical activity of the functionalized triphenylantimony(V) catecholates Ph3Sb[4-O(CH2CH2)2N-3,6-DBCat] (I), Ph3Sb[4,5-Piperaz-3,6-DBCat] (II), and Ph3Sb[4-PhN(CH2CH2)2N-3,6-DBCat] (III) (where [4-O(CH2CH2)2N-3,6-DBCat]2?, [4,5-Piperaz-3,6-DBCat]2?, and [4-PhN(CH2CH2)2N-3,6-DBCat]2? are the dianionic ligands 3,6-di-tert-butyl-4-(morpholin-1-yl)-, 3,6-di-tert-butyl-4,5-(piperazine-1,4-diyl)-, and 3,6-di-tert-butyl-4-(4-phenylpiperazin-1-yl)catecholates, respectively) was studied in reactions with the diphenylpicrylhydrazyl radical during autooxidation of unsaturated fatty (oleic and linoleic) acids with lipid peroxidation of Russian sturgeon (Acipenser gueldenstaedti B.) sperm and human blood erythrocytes in vitro as examples. The EC50 and n DPPH values obtained indicate the high antiradical activity of complexes II and III in the reactions with the stable radical. On the whole, complexes I–III inhibit the lipid peroxidation in both model (oxidation of unsaturated fatty acids) and in vitro experiments. The inhibiting effects of the complexes are comparable with and even, in some cases, higher than those of the known antioxidant ionol. 相似文献
15.
Feixiang Cheng Jishu Chen Fan Wang Ning Tang Longhai Chen 《Transition Metal Chemistry》2011,36(5):573-578
Two polypodands, tetrakis[2-(4,5-diazafluoren-9-ylimino)phenoxymethyl]methane (L1) and 1,1,1-tris[2-(4,5-diazafluoren-9-ylimino)phenoxymethyl]propane (L2), and their corresponding Ru(II) polypyridyl complexes have been synthesized and characterized. The photophysical behaviors
of the two complexes were investigated by UV–vis absorption and emission spectroscopy. They display metal-to-ligand charge
transfer (MLCT) absorptions at around 443 nm in MeCN solution at room temperature and emission at around 573 nm in EtOH:MeOH
(4:1) glassy matrix at 77 K. Electrochemical studies of the two complexes show one Ru(II)-centered oxidation at around 1.35 V
and three ligand-centered reductions. 相似文献
16.
A. I. Poddel’sky I. V. Smolyaninov N. N. Vavilina Yu. A. Kurskii N. T. Berberova V. K. Cherkasov G. A. Abakumov 《Russian Journal of Coordination Chemistry》2012,38(4):284-294
A series of new binuclear bis(catecholate) antimony(V) complexes based on 1,1′-spirobis[3,3-dimethylindanequinone-5,6] with
various substituents at the central antimony atoms, R3Sb(Cat-Spiro-Cat)SbR3 (I–IV) and R3Sb(CatBr-Spiro-BrCat)SbR3 (V–VIII) (R = p-fluorophenyl, phenyl, p-tolyl, and ethyl), were synthesized. Spirobis(catecholates) I–III exhibit two one-electron oxidation waves on the cyclic voltammograms, whereas bromo-substituted spirobis(catecholates) V–VII undergo two-electron oxidation immediately at the first stage. The two-electron oxidation of the complexes results in the
loss of one of the organoantimony fragments and the formation of mononuclear catecholate-quinone complexes (Q-Spiro-Cat)SbR3 or (QBr-Spiro-BrCat)SbR3, respectively. An insignificant delocalization of the charge and spin between two redox centers is observed in the complexes.
The nature of substituents at the antimony atom exerts an effect on the values of redox potentials of the complexes: more
donating groups decrease the oxidation potentials of the catecholate fragments and more withdrawing groups increases these
values. 相似文献
17.
G. K. Fukin M. A. Samsonov A. I. Poddel’sky V. K. Cherkasov 《Russian Chemical Bulletin》2016,65(1):61-66
The theoretical study of the reactivity of catecholate and o-amidophenolate complexes of SbV in the reversible binding of molecular oxygen was performed. The evaluation of the strength of intramolecular interactions in pre-reaction complexes provides the assessment of the strength of oxygen binding in the coordination sphere of Sb. The initial complexes, their transition states, and final spiroendoperoxide complexes were modeled. The calculated activation energies of the reaction and ionization can serve as the energy criteria providing the explanation and prediction of interactions of these complexes with molecular oxygen. 相似文献
18.
Meally ST McDonald C Karotsis G Papaefstathiou GS Brechin EK Dunne PW McArdle P Power NP Jones LF 《Dalton transactions (Cambridge, England : 2003)》2010,39(20):4809-4816
We report the synthesis and magnetic characterisation of a series of planar [M?] (M= Ni(II), Zn(II)) disc complexes [Ni?(OH)?(L?)?](NO?)? (1), [Ni?(OH)?(L?)?](NO?)?·2MeOH (2), [Ni?(OH)?(L?)?](NO?)?·3MeNO? (3), [Ni?(OH)?(L?)?](NO?)?·2MeCN (4), [Zn?(OH)?(L?)?](NO?)?·2MeOH·H?O (5) and [Zn?(OH)?(L?)?](NO?)?·3MeNO? (6) (where HL? = 2-iminomethyl-6-methoxy-phenol, HL? = 2-iminomethyl-4-bromo-6-methoxy-phenol). Each member exhibits a double-bowl pseudo metallocalix[6]arene topology whereby the individual [M?] units form molecular host cavities which are able to accommodate various guest molecules (MeCN, MeNO? and MeOH). Magnetic susceptibility measurements carried out on complexes 1 and 4 indicate weak exchange between the Ni(II) centres. 相似文献
19.
Josane A. LessaAuthor VitaeDébora C. ReisAuthor Vitae Isolda C. MendesAuthor VitaeNivaldo L. SpezialiAuthor Vitae Lucas F. RochaAuthor VitaeValéria R.A. PereiraAuthor Vitae Cristiane M.L. MeloAuthor VitaeHeloisa BeraldoAuthor Vitae 《Polyhedron》2011,30(2):372-380
The antimony(III) complexes [Sb(2Fo4Ph)Cl2] (1), [Sb(2Ac4Ph)Cl2] (2) and [Sb(2Bz4Ph)Cl2] (3) were prepared with N(4)-phenyl-2-formyl- (H2Fo4Ph), 2-acetyl- (H2Ac4Ph) and 2-benzoylpyridine (H2Bz4Ph) thiosemicarbazones. The antimony(III) complexes presented antitrypanosomal activity against the epimastigote and trypomastigote forms of Trypanosoma cruzi. Complexes (1) and (2) exhibited higher activity than the reference drugs benznidazole and nifurtimox. 相似文献
20.
I. V. Smolyaninov A. I. Poddel’skiy N. T. Berberova V. K. Cherkasov G. A. Abakumov 《Russian Journal of Coordination Chemistry》2010,36(9):644-650
The electrochemical properties of catecholate and o-amidophenolate complexes with triphenylantimony(V) with various substituents in the aromatic ring were examined. Introduction
of electron-donating groups into the catecholate ligand or replacement of an O atom (in catecholate) by a N atom (o-amidophenolate) stabilizes the monocationic forms of the complexes obtained by one-electron oxidation. Complexes with electron-withdrawing
substituents undergo irreversible two-electron oxidation resulting in the elimination of o-quinone. Complexes containing electron-withdrawing ligands do not form o-semiquinones and are inert to atmospheric oxygen. According to electrochemical data, oxygen can be bound reversibly by catecholate
complexes containing the electron-donating methoxy groups in the 3,6-di-tert-butylcatecholate ligand and o-amidophenolate derivatives with half-wave oxidation potentials lower than or equal to 0.70 V (vs. Ag/AgCl), which form relatively
stable cationic complexes upon the oxidation. 相似文献