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1.
Liu W Lee K Park M John RP Moon D Zou Y Liu X Ri HC Kim GH Lah MS 《Inorganic chemistry》2008,47(19):8807-8812
Either an S 8 symmetrical 48-membered hexadecanuclear or an S 10 symmetrical 60-membered icosanuclear manganese metallamacrocycle was self-assembled using a manganese ion and a ditopic pentadentate ligand. This was either N-4-phenylbenzoylsalicylhydrazide (H 3pbshz) containing a rigid rod-shaped, bulky biphenyl residue as a terminal N-acyl group or N-3,3-diphenylpropionylsalicylhydrazide (H 3dppshz) containing a flexible beta-branched N-acyl group, but with two sterically bulky phenyl residues at the Cbeta position. The backbone of these metal-organic assemblies is a repeating unit consisting of a -[Mn-N-N-] link that extends to complete either the 48-membered cyclic structure involving 16 manganese(III) centers and 16 ditopic linker ligands or the 60-membered cyclic structure involving 20 manganese(III) centers and 20 ditopic linker ligands (depending on the ligand used). Even though the nuclearity of the metallamacrocycles was different, the successive manganese centers were in the same chiral sequence, ...(LambdaLambdaDeltaDelta)(LambdaLambdaDeltaDelta).... 相似文献
2.
John RP Park J Moon D Lee K Lah MS 《Chemical communications (Cambridge, England)》2006,(35):3699-3701
An extended 36-membered dodecanuclear manganese metallamacrocycle with S12 symmetry has been synthesized using the ligand N-cyclohexanoylsalicylhydrazide (H3chxshz) by a self-assembly that accommodates a cyclooctane of conformationally strained S4 symmetry in its hydrophobic cavity. 相似文献
3.
Lee K John RP Park M Moon D Ri HC Kim GH Lah MS 《Dalton transactions (Cambridge, England : 2003)》2008,(1):131-136
An S6-symmetric hexanuclear gallium metalladiazamacrocycle, [Ga(III)(6)L2(6)S6] with a -(lamda delta)(lamda delta)-chiral sequence and an S-symmetric hexadecanuclear manganese metalladiazamacrocycle, [Mn(III)(16)L2(16)S16] with a -(lamda lamda delta delta)(lamda lamda delta delta)-chiral sequence were prepared using the same N2-trans-cinnamoyl-2-hydroxy-3-naphthoylhydrazide (H3L2) as a bridging pentadentate ligand between the metal centers for the formation of a macrocyclic system. 相似文献
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A novel S4-symmetric icosanuclear manganese metalladiazamacrocycle was synthesized using a pentadentate ligand, N-3-phenyl-trans-2-propenoylsalicylhydrazide (H3L), that has a rigid and bulky terminal N-acyl group. A 20 cyclic repeat of an--(Mn-N-N)--linkage resulted in a highly puckered diaza-bridged 60-membered icosanuclear metallamacrocycle. The steric interaction between the ligands in the cyclic system leads to five consecutive Mn(III) centers in a chemically different--(Mn(A)Mn(B)Mn(C)Mn(D)Mn(E))--environment, with the chiralities of the metal centers being in a rather complicated--(LambdaLambdaDeltaLambdaLambda)(DeltaDeltaLambdaDeltaDelta)--sequence. 相似文献
6.
Ohara T Kume M Narukawa Y Motokawa K Uotani K Nakai H 《The Journal of organic chemistry》2002,67(26):9146-9152
Novel 15-membered macrolides possessing the dilactone skeleton, diolides 13a and 13b, have been synthesized in our research program aimed at finding new antibacterial macrolides. Key strategic elements of the approach include the ring-expanding reaction of 13-membered dilactones, prepared from erythromycin A (Ery-A), to 15-membered dilactones via intramolecular translactonization. The absolute configuration at the regenerated C-8 position of the new diolides was determined by chemical transformation, leading to the corresponding lactam analogues, whose stereochemistry is known in the literature. For further confirmation, X-ray analysis was performed. The X-ray structure determination of 13a revealed a backbone conformation similar to that of Ery-A. Novel 15-membered diolide 13a and the 11,12-diol 18 exhibited antibacterial activities comparable to that of Ery-A. 相似文献
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[structure: see text]. A new 36-membered macrolactone, (25S,27S,29S,33S)-caylobolide A, was isolated from the Bahamian cyanobacterium Lyngbya majuscula. The structure of caylobolide contains an unprecedented repeated unit-a contiguous pentad of 1,5 diols-and a 1,3,5-triol. The relative steroechemistry of the 1,3,5-triol was determined using Kishi's Universal NMR database, and absolute stereochemistry at C25,27,29 and C33 were determined by Mosher's analysis. Caylobolide A exhibited in vitro cytotoxicity against human colon tumor cells (IC50 HCT 116, 9.9 microM). 相似文献
9.
G Zhu YV Geletii C Zhao DG Musaev J Song CL Hill 《Dalton transactions (Cambridge, England : 2003)》2012,41(33):9908-9913
A dodecazinc silicotungstate K(20)Na(2)[Zn(6)(OH)(7)(H(2)O)(Si(2)W(18)O(66))](2)·34H(2)O (1) has been synthesized and characterized by X-ray crystallography, elemental analysis, infrared, UV-vis spectroscopy, cyclic voltammetry, acid-base titration, and DFT calculations. The twelve zinc atoms between the two [Si(2)W(18)O(66)](16-) frameworks make this complex more stable hydrolytically than the heteropolytungstate ligands, [Si(2)W(18)O(66)](16-), themselves. The structurally unique central Zn(12) core is formed by the fusion of two [Zn(6)(OH)(7)(H(2)O)](5+) units through two edge-sharing Zn6 atoms. DFT B3LYP calculations give HOMO-LUMO and (HOMO - 1)-LUMO energy gaps of ~3.65 and 3.91 eV, respectively, as compared to the band gap in ZnO of 3.35 eV. 相似文献
10.
Islam Md. Rafiqul Kazuaki Shimada Shigenobu Aoyagi Yuji Takikawa Chizuko Kabuto 《Heteroatom Chemistry》2004,15(2):175-186
5H-1,2,4-oxathiazoles were efficiently synthesized from 6H-1,3,5-oxathiazine S-oxides by thermal cycloreversion of the substrates and the products were effectively converted into 1,2,4-thiadiazoles. © 2004 Wiley Periodicals, Inc. Heteroatom Chem 15:175–186, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20004 相似文献
11.
Nataliya P. BurkovskayaMarina E. Nikiforova Mikhail A. KiskinAnatoliy S. Lermontov Artem S. BogomyakovVladimir S. Mironov Zhanna V. DobrokhotovaVasyl I. Pekhnyo Aleksei A. SidorovVladimir M. Novotortsev Igor L. Eremenko 《Polyhedron》2011,30(17):2941-2949
New dodecanuclear phenylphosphonate-bridged Co(II) complexes [(μ2-THF)5(η-HPiv)Co12(μ3-OH)4(μ6-O3PPh)4(μ-Piv)12]·THF·2С6Н6 (1·THF·2С6Н6), [(μ2-THF)6Co12(μ3-OH)4(μ6-O3PPh)4(μ-Piv)12]·3THF (2·3THF) and [(μ2-Hmhp)6Co12(μ3-OH)4(μ6-O3PPh)4(μ-Piv)12]·6.5MeCN (3·6.5MeCN) have been synthesized by the reaction of the cobalt(II) pivalate polymer {Co(Piv)2}n (Piv is the pivalate anion), as a source of metal fragments containing cobalt(II) atoms, with potassium phenylphosphonate (K2PO3Ph) in the presence of neutral O-donor additional ligands like molecules of THF or 6-methyl-2-pyridone (Hmhp). The structures of the dodecanuclear complexes 1-3 were determined by using single-crystal X-ray diffraction data. The magnetic properties of the compounds showed that complexes 1 and 3 exhibit antiferromagnetic exchange interactions between the magnetic centers. The stability of compounds 1 and 3 were studied using thermogravimetric analysis. 相似文献
12.
Hexanuclear, octanuclear, and decanuclear manganese metalladiazamacrocycles have been prepared by reacting a series of pentadentate ligands, N-acylsalicylhydrazides (N-(3-methylbutanoyl)salicylhydrazide (H(3)3-mbshz), N-(phenylacetyl)salicylhydrazide (H(3)pashz), N-(3,3-dimethylbutanoyl)salicylhydrazide (H(3)3-dmbshz), N-(2-methylpropanoyl)salicylhydrazide (H(3)2-mpshz), N-((R,S)-2-methylbutanoyl)salicylhydrazide (H(3)RS-2-mbshz), N-((S)-2-methylbutanoyl)salicylhydrazide (H(3)S-2-mbshz), and N-(2,2-dimethylpropanoyl)salicylhydrazide (H(3)2-dmpshz)), with manganese(II) acetate tetrahydrate. The self-assembled, supramolecular complexes assume a nearly planar cyclic structure with an -(Mn-N-N)(n) backbone and measure approximately 2.1, approximately 2.3, and approximately 2.6 nm in outer diameters for n = 6, 8, and 10, respectively. The chiralities of the manganese centers on the metalladiazamacrocycle occur in alternating ...LambdaDeltaLambdaDelta... configurations. While beta-branched N-acylsalicylhydrazides (H(3)3-mbshz, H(3)pashz, H(3)3-dmbshz) with a sterically flexible Calpha methylene group yield 18-membered hexanuclear manganese metalladiazamacrocycles of S(6) point group symmetry, alpha-branched N-acylsalicylhydrazides lead to 24-membered octanuclear manganese metalladiazamacrocycles or 30-membered decanuclear manganese metalladiazamacrocycles depending on the size of the N-acyl substituents. The alpha-branched H(3)2-mpshz ligand with the sterically least demanding isopropyl tail at the N-acyl position yields a 24-membered octanuclear manganese metalladiazamacrocycle of S(8) point group symmetry, but other alpha-branched N-acylsalicylhydrazides such as H(3)RS-2-mbshz, H(3)S-2-mbshz, and H(3)2-dmpshz lead to 30-membered decanuclear manganese metalladiazamacrocycles of S(10) point group symmetry. The magnetic properties of the metalladiazamacrocycles are characterized by a weak antiferromagnetic exchange interaction, with J(eff) = -8.5 to -3.8 K between the Mn(3+) ion spins with S = 2 in the cyclic system. 相似文献
13.
Zou LF Zhao L Guo YN Yu GM Guo Y Tang J Li YH 《Chemical communications (Cambridge, England)》2011,47(30):8659-8661
A novel dodecanuclear wheel with ten Dy(III) ions and two Co(II) ions bridged by four Schiff-base ligands and sixteen acetates represents the highest-nuclearity 3d-4f example of its type displaying single-molecule magnet behaviour. 相似文献
14.
A.N. Nesmeyanov G.G. Aleksandrov A.B. Antonova K.N. Anisimov N.E. Kolobova Yu.T. Struchkov 《Journal of organometallic chemistry》1976,110(2):C36-C38
Three novel stable complexes of manganese were prepared by interaction of [(η5-C5H5)Mn(CO)2 (THF)] with phenylacetylene. X-ray structure analysis of two of the complexes established the presence of a phenylvinylidene ligand. In [(η5-C5H5Mn(CO)2(CCHPh)] this ligand forms an unusual double MnC bond and in [(η5-C5H5)Mn2(CO)4(CCHPh)] it acts as a bridge strengthening the MnMn bond. 相似文献
15.
Basler R Chaboussant G Sieber A Andres H Murrie M Kögerler P Bögge H Crans DC Krickemeyer E Janssen S Mutka H Müller A Güdel HU 《Inorganic chemistry》2002,41(22):5675-5685
The magnetic exchange interactions in the mixed-valence dodecanuclear polyoxovanadate compounds Na(4)[V(IV)(8)V(V)(4)As(III)(8)O(40)(H(2)O)].23H(2)O, Na(4)[V(IV)(8)V(V)(4)As(III)(8)O(40)(D(2)O)].16.5D(2)O, and (NHEt(3))(4)[V(IV)(8)V(V)(4)As(III)(8)O(40)(H(2)O)].H(2)O were investigated by an inelastic neutron scattering (INS) study using cold neutrons. In addition, the synthesis procedures and the single-crystal X-ray structures of these compounds have been investigated together with the temperature dependence of their magnetic susceptibilities. The magnetic properties below 100 K can be described by simply taking into account an antiferromagnetically exchange coupled tetramer, consisting of four vanadium(IV) ions. Up to four magnetic transitions between the cluster S = 0 ground state and excited states could be observed by INS. The transition energies and the relative INS intensities could be modeled on the basis of the following exchange Hamiltonian: H(ex) = -2J(12)(xy)[S(1x)S(2x)+ S(3x)S(4x)+ S(1y)S(2y)+ S(3y)S(4y)] - 2J(12)(z)[(S(1z)S(2z)+ S(3z)S(4z)] - 2J(23)(xy)[(S(2x)S(3x)+ S(1x)S(4x)+ S(2y)S(3y)+ S(1y)S(4y)] - 2J(23)(z)[(S(2z)S(3z)+ S(1z)S(4z)]. The following sets of parameters were derived: for Na(4)[V(12)As(8)O(40)(H(2)O)].23H(2)O, J(12)(xy)() = J(12)(z)= -0.80 meV, J(23)(xy) = J(23)(z) = -0.72 meV; for Na(4)[V(12)As(8)O(40)(D(2)O)].16.5D(2)O, J(12)(xy) = J(12)(z) = J(23)(xy) = J(23)(z = -0.78 meV; for (NHEt(3))(4)[V(12)As(8)O(40)(H(2)O)].H(2)O, J(12)(xy) = -0.80 meV, J(12)(z) = -0.82 meV, J(23)(xy)() = -0.67 meV, J(23)(z) = -0.69 meV. This study of the same [V(12)As(8)]-type cluster in three different crystal environments allows us to draw some conclusions concerning the applicability on INS in the area of nondeuterated molecular spin clusters. In addition, the effects of using nondeuterated samples and different sample container shapes for INS were evaluated. 相似文献
16.
Brechin EK Cador O Caneschi A Cadiou C Harris SG Parsons S Vonci M Winpenny RE 《Chemical communications (Cambridge, England)》2002,(17):1860-1861
The synthesis, structural characterisation and preliminary magnetic studies of a Co12 wheel are reported; the magnetic investigations reveal that the electronic ground state has a spin S = 6, which corresponds to ferromagnetic interactions between the twelve Co(II) ions. 相似文献
17.
Valeriu Mereacre Yanhua Lan Wolfgang Wernsdorfer Christopher E. Anson Annie K. Powell 《Comptes Rendus Chimie》2012,15(7):639-646
A series of four isostructural dodecanuclear complexes [MnIII9MnII2LnIII(O)8(OH)(piv)16(NO3)(CH3CN)]·xCH3CN·yC7H16 (piv = pivalate; x = ½, y = ¾, Ln = Tb (1); x = 2, y = ½, Ln = Dy (2), Ho (3), and Y (4)) has been prepared for which the structural motif described as ‘a lanthanide ion nested in a large manganese shell’ is observed. All compounds show out-of-phase signals in their ac susceptibilities, and their single-molecule magnet behaviour was confirmed by single-crystal micro-SQUID studies of 1-3 which show hysteresis loops of molecular origin at T < 1.0 K. The SMM behaviour observed in compounds 1-3 is more pronounced than that for 4, which contains the diamagnetic YIII ion. This is principally the result of ferromagnetic coupling between the paramagnetic anisotropic LnIII ions (TbIII, DyIII and HoIII) and the manganese shell, which enhances the total spin ground state of the complexes. 相似文献
18.
Jin Chul Jung Christoph Baehr Chang-Hun Lee Sang-Bong Park Young-Sub Son Kwang S. Kim 《Macromolecular Symposia》1999,142(1):101-109
When various properties of poly[2,5-di(n-alkyloxy)methyl-p-phenylenenaphthalene-1,8:4,5-diimide]s (Cm-NAPIs, m = 4, 6, 8) as aromatic 6-membered polyimides were compared with those of poly[2,5-di(n-alkyloxy)methyl-p-phenylenepyromellitimide]s (Cm-PYPIs, m = 4, 6, 8) as 5-membered ones, it was deduced that O atoms of C=O of Cm-NAPIs are not coplanar with their imide ring plane. This noncoplanarity led us necessarily to assuming that the 6-membered ring polyimide chains should have cis/trans-like isomeric structures. Detailed spectroscopic studies and ab initio calculations for appropriate model compounds are provided to support our assumption. 相似文献
19.
Masahiko Isaka Panida Chinthanom Sukitaya Veeranondha Sumalee Supothina J. Jennifer Luangsa-ard 《Tetrahedron》2008,64(49):11028-11033
Two novel cyclopropyl diketones, hamavellone A (1) and B (2), and two new 14-membered nonaketide macrolactones, hamigeromycin A (3) and B (4), together with six known compounds, 89-250904-F1 (radicicol analogue A, 5), pseurotin A (6), emodin (7), ω-hydroxyemodin (8), and emodin bianthrones (9 and 10) were isolated from the soil fungus Hamigera avellanea BCC 17816. The structures of the new compounds were defined by analysis of NMR and MS data. The absolute stereochemistry of 3 was addressed by chemical correlation to 5. Hamavellone B (2) exhibited antimalarial activity with an IC50 of 5.2 μg/mL, whereas it also showed comparable cytotoxicity. 相似文献
20.
The preparation of cyclic 10-membered tetrahydroxy enediynes is reported. The synthesis starts from tartaric acid and allows the control of the relative stereochemistry. Acetal protection of the 2,3-hydroxy groups stabilizes the enediyne during synthesis. Removal of the cyclic protecting group with EtSH/TFA transforms the stable compounds into reactive enediynes, and the rate constants of their cyclization were determined in benzene and water. The cytoxicity of the activated compounds was assayed against tumor cells in vitro, but the growth inhibitory effect was weak compared to cisplatin. 相似文献