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Clegg JK Lindoy LF McMurtrie JC Schilter D 《Dalton transactions (Cambridge, England : 2003)》2005,(5):857-864
A range of 1,3-aryl linked, bis-beta-diketone derivatives (LH2) has been employed to synthesise neutral bis(ligand), dinuclear complexes incorporating square-planar copper(II) and tris(ligand) dinuclear helical derivatives containing octahedral iron(III). The 1H NMR spectra of the free ligands contain singlet peaks at ca. 16.2 ppm, indicative of enolic protons, confirming that the (bis) enol tautomer is present in solution. An X-ray structure of a ligand from the series incorporating tert-butyl terminal substituents confirms that the same tautomer persists in the solid and that the relative orientation of the bis-beta-diketone fragments is such that the coordination vectors lie at approximately 120 degrees to each other. The planar, dinuclear copper complexes form 1 : 2 adducts with pyridine and 4-(dimethylamino)pyridine, confirmed by X-ray structures, that incorporate five-coordinate metal centres. Based on this behaviour, the prospect of linking copper centres in the dinuclear complexes using the difunctional heterocyclic bases, 4,4'-bipyridine, 4,4'-trans-azopyridine and pyrazine as co-ligands has been probed. However, 4,4'-bipyridine was observed to coordinate through only one of its heterocyclic nitrogen atoms in the solid state to form a 1 : 2 ([Cu2(L)2]: 4,4'-bipyridine) adduct, analogous to the structures obtained with the above mono-functional nitrogen bases. Nevertheless, an X-ray structure determination shows that the related difunctional base, 4,4'-trans-azopyridine, coordinates in a bridging fashion via both its heterocyclic nitrogen atoms on alternate sides of each planar [Cu2(L)2] unit to produce an infinite one dimensional metallo chain. In contrast, with pyrazine, a new neutral, discrete assembly of type [Cu4(L)4(pyrazine)2] is formed. The X-ray structure shows that two planar dinuclear complexes are linked by two pyrazine molecules in a sandwich arrangement such that the coordination environment of each copper ion is approximately square pyramidal with the overall tetranuclear structure thus taking the form of a 'dimer of dimers'. 相似文献
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L. F. Lindoy 《Journal of the Iranian Chemical Society》2004,1(1):1-9
The selective use of tert-butoxycarbonyl protecting group chemistry has enabled efficient syntheses of multilinked macrocyclic derivatives incorporating tetraaza and aza-thia donor rings. Mixed ring species have also been prepared as well as a dendrimer incoporating nine N2S2-donor macrocyclic sites. The interaction of these species with selected metal ions is discussed. A series of cage molecules with varying cavity sizes has been prepared and their interaction with both (selected) metal ions and small molecules described. The formation of new large molecular squares and catenanes involving self-assembly is also presented. 相似文献
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Tomoaki Hiraoka Dr. Ryo Ohtani Dr. Masaaki Nakamura Prof. Dr. Leonard F. Lindoy Prof. Dr. Shinya Hayami 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(31):7521-7525
Control of ion arrangements in ionic liquids represents a major challenge owing to the presence of the predominant coulombic interactions between cationic and anionic ion species that forms the coulombic ordering. Here, water-induced ion rearrangement in a room-temperature ionic liquid (RT-IL) metal complex, (1-ethyl-3-methylimidazolium)2[MnN(CN)4], is demonstrated through coordinative interactions between anions. Solidification occurred, which was associated with the formation of a “separated” structure consisting of cation columns and anionic cyanide-bridged one-dimensional coordination polymers. The energy diagram is in accord with the resultant RT-IL incorporating mononuclear [MnN(CN)4]2− molecules being a kinetic phase stabilized by inter-ion repulsions of the anionic divalent metal complex moieties. Water acts to decrease the coulombic interactions, including repulsion, giving rise to breaking of the coulombic ordering arising from coordination bond formation in the IL phase. 相似文献
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Fumiya Kobayashi Dr. Ryo Ohtani Saki Teraoka Dr. Masaki Yoshida Prof. Dr. Masako Kato Dr. Yingjie Zhang Prof. Dr. Leonard F. Lindoy Prof. Dr. Shinya Hayami Dr. Masaaki Nakamura 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(23):5875-5879
Luminescent ZnII clusters [Zn4L4(μ3-OMe)2X2] (X=SCN ( 1 ), Cl ( 2 ), Br ( 3 )) and [Zn7L6(μ3-OMe)2(μ3-OH)4]Y2 (Y=I− ( 4 ), ClO4− ( 5 )), HL=methyl-3-methoxysalicylate, exhibiting blue fluorescence at room temperature (λmax=416≈429 nm, Φem=0.09–0.36) have been synthesised and investigated in detail. In one case the external heavy-atom effect (EHE) arising the presence of iodide counter anions yielded phosphorescence with a long emission lifetime (λmax=520 nm, τ=95.3 ms) at 77 K. Single-crystal X-ray structural analysis and time-dependent density-functional theory (TD-DFT) calculations revealed that their emission origin was attributed to the fluorescence from the singlet ligand-centred (1LC) excited state, and the phosphorescence observed in 4 was caused by the EHE of counter anions having strong CH−I interactions. 相似文献
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Ji-Eun Lee Jai Young Lee Joobeom Seo So Young Lee Hyun Jee Kim Sunhong Park Ki-Min Park Leonard F. Lindoy Shim Sung Lee 《Polyhedron》2008
A comparative investigation of the coordination behaviour of the 17-membered, N3O2-donor macrocycle, 1,12,15-triaza-3,4:9,10-dibenzo-5,8-dioxacycloheptadecane, L, with the soft metal ions Ag(I), Cd(II), Hg(II), and Pd(II) is reported. The X-ray structures of 12 complexes have been determined and a range of structural types, including both mononuclear and dinuclear species, shown to occur. In particular cases the effect of anion variation on the resulting structures has been investigated; L reacts with AgX (X = NO3, ClO4, PF6, OTf and CN) to yield related 2:2 (metal:ligand) complexes of types [Ag2L2(NO3)2] (1), [Ag2L2](ClO4)2 · 2DMF (2), [Ag2L2](PF6)2 · 2DMF (3), [Ag2L2](OTf)2 (4) and [Ag2L2(μ-CN)][Ag(CN)2] · H2O (5). In all five complexes the ether oxygens of each ring are unbound. In 1–4 the macrocycles are present in sandwich-like arrangements that shield the dinuclear silver centres, with each silver bonded to two nitrogen donors from one L and one nitrogen from a second L. A Ag···Ag contact is present between each metal centre such that both centres can be described as showing distorted tetrahedral geometries. In the case of 5 a rare single μ2-κC:κC symmetrically bridging two-electron-donating cyano bridge links silver ions [Ag···Ag distance, 2.7437(10) Å]; the macrocyclic ligands are orientated away from the dinuclear metal centres. In contrast to the behaviour of silver, reaction of cadmium(II) perchlorate with L resulted in a mononuclear sandwich-like complex of type [CdL2](ClO4)2 · CH3CN (6). Again, the ether oxygens do not coordinate, with each L binding to the cadmium centre only via its three nitrogen donors in a facial arrangement such that a distorted octahedral coordination geometry is attained. Reaction of L with HgX2 (X = ClO4, SCN and I) yielded the monomeric species [HgL(ClO4)2] (7), [HgL(SCN)2]·CH3CN (8) and [Hg2L2](HgI4)2 · 2L (9), in which all five donors of L are bound to the respective mercury centres. However, reaction of L with Hg(NO3)2 in dichloromethane/methanol gave a mononuclear sandwich-like complex [HgL2](NO3)2 · 2CH3OH (10) without anion coordination. Reaction of K2PdCl4 and Pd(NO3)2 with L yielded the 1:1 complexes [PdLCl]Cl · H2O (11) and [PdL(NO3)]NO3 · CH3OH (12), respectively, in which the metal is bound to three nitrogen donors from L along with the corresponding chloride or nitrate anion. Each palladium adopts a distorted square-planar coordination geometry; once again the ether oxygens are not coordinated. 相似文献
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Clegg JK Bray DJ Gloe K Gloe K Jolliffe KA Lawrance GA Lindoy LF Meehan GV Wenzel M 《Dalton transactions (Cambridge, England : 2003)》2008,(10):1331-1340
Uncharged complexes, formulated as trimeric metallocycles of type [M3(L(1))3(Py)6] (where M = cobalt(II), nickel(II) and zinc(II) and L(1) is the doubly deprotonated form of a 1,4-phenylene linked bis-beta-diketone ligand of type 1,4-bis(RC(O)CH2C(O))C6H4 (R = t-Bu)) have been synthesised, adding to related, previously reported complexes of these metals with L(1) (R = Ph) and copper(ii) with L(1) (R = Me, Et, Pr, t-Bu, Ph). New lipophilic ligand derivatives with R = hexyl, octyl or nonyl were also prepared for use in solvent extraction experiments. The X-ray structures of H2L(1) (R = t-Bu) and of its trinuclear (triangular) nickel(II) complex [Ni3(L(1))3(Py)6].3.5Py (R = t-Bu) are also presented. Electrochemical studies of H2L(1), [Co3(L(1))3(Py)6], [Ni3(L(1))3(Py)6], [Cu3(L(1))3], [Zn3(L(1))3(Py)6] and [Fe4(L(1))6] (all with R = t-Bu) show that oxidative processes for the complexes are predominantly irreversible, but several examples of quasireversible behaviour also occur and support the assignment of an anodic process, seen between +1.0 and +1.6 V, as involving metal-centred oxidations. The reduction behaviour for the respective metal complexes is not simple, being irreversible in most cases. Solvent extraction studies (water/chloroform) involving the systematic variation of the metal, bis-beta-diketone and heterocyclic base concentrations have been performed for cobalt(II) and zinc(II) using a radiotracer technique in order to probe the stoichiometries of the respective extracted species. Significant extraction synergism was observed when 4-ethylpyridine was also present with the bis-beta-diketone ligand in the chloroform phase. Competitive extraction studies demonstrated a clear uptake preference for copper(II) over cobalt(II), nickel(II), zinc(II) and cadmium(II). 相似文献
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Xue-Kui Ji Leonard F. Lindoy Brian W. Skelton Allan H. White 《Journal of inclusion phenomena and macrocyclic chemistry》2011,71(3-4):589-592
The synthesis and X-ray structure of a new pendant-arm derivative of a parent 14-membered N2O2-donor macrocycle bearing an N-substituted 6-methylene-2,4-dimethylphenol group is presented. A single crystal X-ray study shows a strong intramolecular hydrogen-bond between the pendant phenol proton and the tertiary nitrogen of the macrocyclic ring, which may inhibit its ability to bind with selected transition and post-transition metal ions. 相似文献