Journal of The Chemical Society-dalton Transactions最新文献_第10页

The binding of Ni(II) ions to terminally blocked hexapeptides derived from the metal binding -ESHH- motif of histone H2A Ni(II)离子与组蛋白H2A金属结合- eshh -基序的末端阻断六肽的结合

Journal of The Chemical Society-dalton Transactions Pub Date : 2002-11-12 DOI: 10.1039/B206585A

M. Mylonas, A. Krężel, J. Plakatouras, N. Hadjiliadis, W. Bal

{"title":"The binding of Ni(II) ions to terminally blocked hexapeptides derived from the metal binding -ESHH- motif of histone H2A","authors":"M. Mylonas, A. Krężel, J. Plakatouras, N. Hadjiliadis, W. Bal","doi":"10.1039/B206585A","DOIUrl":"https://doi.org/10.1039/B206585A","url":null,"abstract":"The coordination properties of Ni(II) ions towards the terminally blocked (CH3CONH- and -CONH2) hexapeptides -TESHHK-, -TASHHK-, -TEAHHK-, -TESAHK- and -TESHAK- were studied by using potentiometric and spectroscopic techniques (UV/Vis, CD, NMR). The peptides were chosen in such a way as to compare the effect of Glu, Ser and His residues on the stability, the coordination and hydrolytic abilities of the complexes formed. All peptides bind to Ni(II) ions initially through one or two imidazole nitrogens in weakly acidic and neutral solutions forming slightly distorted octahedral complexes. At higher pH values, a series of square-planar complexes are formed, where Ni(II) ions bind simultaneously through an imidazole and three amide nitrogens in an equatorial plane. This proposed conformation includes the participation of only one imidazole nitrogen, in the case of all peptides, in the coordination sphere of Ni(II) ions. In basic solutions, the peptides -TASHHK- and -TESAHK- were hydrolyzed in a Ni(II)-assisted fashion. No hydrolytic processes were noticed in peptides -TEAHHK- and -TESHAK- where the Ser or His-5 residues are replaced with the Ala residue. The Ni(II)-assisted hydrolysis of the analogues of -TESHHK- may provide an insight into the novel mechanism of genotoxicity, combining the damage to the nucleosome with the generation of further toxic Ni(II) species.","PeriodicalId":17317,"journal":{"name":"Journal of The Chemical Society-dalton Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78457588","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 32

Synthesis and catalytic activity of three-coordinate zinc cations 三配位锌阳离子的合成及其催化活性

Journal of The Chemical Society-dalton Transactions Pub Date : 2002-11-12 DOI: 10.1039/B208165M

Mark D. Hannant, M. Schormann, M. Bochmann

引用次数: 69

Reactivity of five- and six-coordinated solvates. A complex formation and crystallographic study of the nickel(II) bromide and iodide systems in dimethyl sulfoxide and N,N′-dimethylpropyleneurea 五和六配位溶剂化物的反应性。二甲基亚砜和N,N ' -二甲基丙烯脲中镍(II)溴化和碘化体系的络合物形成和结晶学研究

Journal of The Chemical Society-dalton Transactions Pub Date : 2002-11-12 DOI: 10.1039/B204128F

Dorota Bobicz, O. Kristiansson, I. Persson

{"title":"Reactivity of five- and six-coordinated solvates. A complex formation and crystallographic study of the nickel(II) bromide and iodide systems in dimethyl sulfoxide and N,N′-dimethylpropyleneurea","authors":"Dorota Bobicz, O. Kristiansson, I. Persson","doi":"10.1039/B204128F","DOIUrl":"https://doi.org/10.1039/B204128F","url":null,"abstract":"The complex formation equilibria for the nickel(II)-bromide and -iodide systems in dimethyl sulfoxide and the bromide system in N,N′-dimethylpropyleneurea have been studied calorimetrically and spectrophotometrically at 298 K. An ionic strength of 0.1 mol dm−3 was kept constant using tetrabutylammonium perchlorate as supporting electrolyte. Two stable mononuclear bromo-complexes are formed in dilute N,N′-dimethylpropyleneurea solution with β1 \u0000= \u0000(2.0 ± 0.4) \u0000× 103 mol−1 dm3 and β2 \u0000= \u0000(7.2 ± 1.5) \u0000× 105 mol−2 dm6, whereas nickel(II) does not form any measurable complexes with bromide and iodide ions in dimethyl sulfoxide solution. The structures of the solids precipitating from concentrated solutions of nickel(II)-bromide and -chloride in the respective solvents have been determined by X-ray diffraction. The solid precipitating from a concentrated N,N′-dimethylpropyleneurea solution of nickel(II) bromide is a stable pseudotetrahedral bis(N,N′-dimethylpropyleneurea)dibromonickel(II) complex. Precipitation of nickel(II) chloride from a dimethyl sulfoxide solution results in hexakis(dimethyl sulfoxide)nickel(II) tetrachloronickelate(II), which is gradually transformed to hexakis(dimethyl sulfoxide)nickel(II) chloride, the most enthalpy stabilised complex. Hexakis(dimethyl sulfoxide)nickel(II) bromide precipitates from a concentrated dimethyl sulfoxide solution of nickel(II) bromide.","PeriodicalId":17317,"journal":{"name":"Journal of The Chemical Society-dalton Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83029898","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 14

Structural analysis and magnetic properties of the 1D [Fe(dca)2bipy(H2O)]·1/2H2O and the 3D [Ni(dca)2bipy] (dca = dicyanamide; bipy = 4,4′-bipyridine) 一维[Fe(dca)2bipy(H2O)]·1/2H2O和三维[Ni(dca)2bipy] (dca =双氰胺)的结构分析和磁性能Bipy = 4,4 ' -联吡啶)

Journal of The Chemical Society-dalton Transactions Pub Date : 2002-11-12 DOI: 10.1039/B206069H

Susana Martín, M. Barandika, J. M. Ezpeleta, R. Cortés, J. D. Larramendi, L. Lezama, T. Rojo

引用次数: 25

Cyclooctatetraene ditungsten alkoxides: W2(μ-η5,η5-COT)(OR)4, where R = CH2tBu, iPr, and tBu 环己四烯二钨烷氧化物:W2(μ-η5，η5-COT)(OR)4，其中R = CH2tBu, iPr，和tBu

Journal of The Chemical Society-dalton Transactions Pub Date : 2002-11-12 DOI: 10.1039/B205130N

B. Bursten, M. Chisholm, M. Drummond, J. Gallucci, Carl B. Hollandsworth

{"title":"Cyclooctatetraene ditungsten alkoxides: W2(μ-η5,η5-COT)(OR)4, where R = CH2tBu, iPr, and tBu","authors":"B. Bursten, M. Chisholm, M. Drummond, J. Gallucci, Carl B. Hollandsworth","doi":"10.1039/B205130N","DOIUrl":"https://doi.org/10.1039/B205130N","url":null,"abstract":"Four equivalents of neopentanol, isopropanol, or t-butanol react with the cyclooctatetraene-bridged dimethylamide, W2(μ-η5,η5-COT)(NMe2)4, to give the corresponding tetraalkoxides, W2(μ-η5,η5-COT)(OR)4, in greater than 70% yields. The alkoxide W2(COT)(OCH2tBu)4 can be made alternatively by reacting W2(COT)(OtBu)4 with 4 equivalents of neopentanol. X-ray diffraction data for the t-butoxide compound indicate a μ-η5,η5-COT ligand spans a W–W bond of distance 2.3887(1) \u0000A. The t-butoxide is very similar in most structural parameters to the known W2(COT)(NMe2)4 precursor as well as the bis-allyl compound W2(allyl)2(NMe2)4. The COT ring is fluxional about the metal–metal fragment, undergoing rapid 1,2-shifts on the NMR timescale as determined by 1H EXSY NMR. The purple alkoxides exhibit maximum absorptions around 580 nm (e \u0000∼ 1700 M−1 cm−1) in the visible region of the electronic absorption spectrum. This transition agrees well with DFT calculations on the model compound W2(μ-η5,η5-COT)(OH)4 that reveal the calculated HOMO–LUMO gap to be a 1.94 eV transition involving principally the metal d orbitals. The calculations also reveal the structure with an antifacial (η5,η5)-COT to be 13.7 kcal mol−1 more stable than the corresponding synfacial (η4,η4)-COT structure. In related studies, COT did not form adducts with W2(OCH2tBu)6(py)2, W2(OtBu)6, or W2(OCH2tBu)8 even upon heating to 80 °C for several hours.","PeriodicalId":17317,"journal":{"name":"Journal of The Chemical Society-dalton Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90173770","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 6

Rhenium(I) tricarbonyl complexes with mercaptoimidazolylborate ligands bearing piperazine fragments 含哌嗪片段的三羰基硫代咪唑硼酸配体铼配合物

Journal of The Chemical Society-dalton Transactions Pub Date : 2002-11-12 DOI: 10.1039/B206603N

R. Garcia, Y. Xing, A. Paulo, A. Domingos, I. Santos

{"title":"Rhenium(I) tricarbonyl complexes with mercaptoimidazolylborate ligands bearing piperazine fragments","authors":"R. Garcia, Y. Xing, A. Paulo, A. Domingos, I. Santos","doi":"10.1039/B206603N","DOIUrl":"https://doi.org/10.1039/B206603N","url":null,"abstract":"Reaction of an adequate borohydride salt with the functionalized mercaptoimidazoles timHMe,pip 1 or timHMe,CH2-pip 2 have led to Na[H2B(timMe,pip)2] 3, Na[H2B(timMe,CH2-pip)2] 4, Li[H(Ph)B(timMe)(timMe,pip)2] 6 and Li[H(Ph)B(timMe)(timMe,CH2-pip)2] 7 \u0000(timHMe = 1-methyl-2-mercaptoimidazole; timHMe,pip = 1-methyl-5-[(4-(2′-methoxyphenyl)-1-piperazinyl)carbonyl]-2-mercaptoimidazole; timHMe,CH2pip = 1-methyl-5-[(4-(2′-methoxyphenyl)-1-piperazinyl)methyl]-2-mercaptoimidazole). These symmetric and assymmetric functionalized bis(mercaptoimidazolyl)borates, carrying a piperazine fragment, react readily with (NEt)4[Re(CO)3Br3] giving [Re{κ3-H(μ-H)B(timMe,pip)2}(CO)3] 8, [Re{κ3-H(μ-H)B(timMe,CH2-pip)2}(CO)3] 9, [Re{κ3-Ph(μ-H)B(timMe)(timMe,pip)}(CO)3] 10 and [Re{κ3-Ph(μ-H)B(timMe)(timMe,CH2-pip)}(CO)3] 11. The organometallic complexes 8–11 are valuable models for the development of specific radiopharmaceuticals for imaging serotonergic CNS receptors. The new compounds (1–11) have been characterized by the usual analytical techniques (C, H, N analysis; IR and 1H NMR spectroscopies), and by X-ray diffraction analysis in the case of 8.","PeriodicalId":17317,"journal":{"name":"Journal of The Chemical Society-dalton Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79835116","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 27

An unusual pendant-arm macrocycle formed by condensation of a cobalt(III) tripodal complex with methanal 由钴(III)三足配合物与甲醇缩合形成的一种不寻常的垂臂大环

Journal of The Chemical Society-dalton Transactions Pub Date : 2002-11-12 DOI: 10.1039/B205832D

P. M. Angus, R. J. Geue, N. B. Jensen, F. Larsen, C. Qin, A. Sargeson

引用次数: 7

A comparative investigation of supramolecular structures involving copper(II) complexes of imidazolinylalkanimidamides 咪唑啉烷酰胺类铜(II)配合物超分子结构的比较研究

Journal of The Chemical Society-dalton Transactions Pub Date : 2002-11-12 DOI: 10.1039/B207031F

Michael M. Bishop, L. Lindoy, D. J. Miller, Peter Turner

引用次数: 12

Supramolecular anion binding by the [ZnCl(HpztBu)3]+ cation (HpztBu = 5-tert-butylpyrazole) [ZnCl(HpztBu)3]+阳离子(HpztBu = 5-叔丁基吡唑)的超分子阴离子结合

Journal of The Chemical Society-dalton Transactions Pub Date : 2002-11-12 DOI: 10.1039/B207541P

Sylvie L. Renard, C. Kilner, J. Fisher, M. Halcrow

{"title":"Supramolecular anion binding by the [ZnCl(HpztBu)3]+ cation (HpztBu = 5-tert-butylpyrazole)","authors":"Sylvie L. Renard, C. Kilner, J. Fisher, M. Halcrow","doi":"10.1039/B207541P","DOIUrl":"https://doi.org/10.1039/B207541P","url":null,"abstract":"Reaction of ZnCl2 with three molar equivalents of 3{5}-tert-butylpyrazole (HpztBu) yields [ZnCl(HpztBu)3]Cl (1). Treatment of 1 with an appropriate Ag(I) or Tl(I) salt gives [ZnCl(HpztBu)3]X (X− \u0000= BF4−, 4; X− \u0000= ClO4−, 5; X− \u0000= NO3−, 6; X− \u0000= CF3SO3−, 7; X− \u0000= PF6−, 8). Crystal structures of all of the complexes show a [ZnCl(HpztBu)3]+ cation, with (for 1 and 4-7) only small deviations from C3v symmetry, with the tert-butyl groups forming a bowl-shaped cavity on one face of the complex. The X− anion binds within this cavity, via hydrogen bonding to the three pyrazole N–H groups. For 8, the PF6− guest only interacts with two N–H donors, the third pyrazole ring being twisted away from the anion. We attribute this to steric repulsions between the third ligand and the PF6− anion, which is larger than the other guests used in this study. 1H, 13C and 19F NMR, ESMS and IR studies provide good circumstantial evidence for these structures being retained in solution, although the guest anions undergo rapid intermolecular exchange by NMR that cannot be frozen out above 190 K.","PeriodicalId":17317,"journal":{"name":"Journal of The Chemical Society-dalton Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73603556","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 23

Polydentate ligand construction: preparation of oxime–imine complexes via intramolecular condensation reactions 多齿配体结构:通过分子内缩合反应制备肟-亚胺配合物

Journal of The Chemical Society-dalton Transactions Pub Date : 2002-11-12 DOI: 10.1039/B205956H

Carl A. Otter, R. Hartshorn

引用次数: 4