首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
The templated synthesis of organic macrocycles containing rings of up to 96 atoms and three 2,2′‐bipyridine (bpy) units is described. Starting with the bpy‐centred ligands 5,5′‐bis[3‐(1,4‐dioxahept‐6‐enylphenyl)]‐2,2′‐bipyridine and 5,5′‐bis[3‐(1,4,7‐trioxadec‐9‐enylphenyl)]‐2,2′‐bipyridine, we have applied Grubbs’ methodology to couple the terminal alkene units of the coordinated ligands in [FeL3]2+ complexes. Hydrogenation and demetallation of the iron(II)‐containing macrocyclic complexes results in the isolation of large organic macrocycles. The latter bind {Ru(bpy)2} units to give macrocyclic complexes with exocyclic ruthenium(II)‐containing domains. The complex [Ru(bpy)2(L)]2+ (isolated as the hexafluorophosphate salt), in which L=5,5′‐bis[3‐(1,4,7,10‐tetraoxatridec‐12‐enylphenyl)]‐2,2′‐bipyridine, undergoes intramolecular ring‐closing metathesis to yield a macrocycle which retains the exocyclic {Ru(bpy)2} unit. The poly(ethyleneoxy) domains in the latter macrocycle readily scavenge sodium ions, as proven by single‐crystal X‐ray diffraction and atomic absorption spectroscopy data for the bulk sample. In addition to the new compounds, a series of model complexes have been fully characterized, and representative single‐crystal X‐ray structural data are presented for iron(II) and ruthenium(II) acyclic and macrocyclic species.  相似文献   

2.
Two new flexible extended dialdehydes (H2hpdd and H2pdd) with different functional pendant arms (? CH2CH2PhOH and ? CH2CH2Ph) have been synthesized and reacted with 1,2‐bis(2‐aminoethoxy)ethane to prepare Schiff‐base macrocyclic complexes in the presence of a ZnII‐ion template. As a result, two preorganized dinuclear ZnII intermediates ( 1 and 2 ), as well as two 42‐membered folded [2+2] macrocyclic dinuclear ZnII complexes ( 3 and 4 ), were produced. The central zinc ions in compounds 1 – 4 showed distinguishable coordination patterns with the dialdehydes and the [2+2] macrocyclic ligands, in which a subtle pH‐adjustment function of the two pendant arms (with or without the phenolic hydroxy group) was believed to play a vital role. Furthermore, cation‐ and anion‐recognition experiments for complexes 3 and 4 revealed that they could selectively recognize acetate ions by the formation of 1:1 stoichiometric complexes, as verified by changes in their UV/Vis and MS (ESI) spectra and even by the naked eye.  相似文献   

3.
Three novel Zn(II) complexes,[Zn4L1Cl4]-3H2O(1),[Zn4L2Cl4]-2DMF(2) and[Zn4L3Cl4]H2O(3),have been synthesized and structurally characterized.In these complexes,interesting 32-membered dodecadentate macrocyclic ligands were generated in situ by ’2 + 2’ type condensation reactions between a tetraamine and various dialdehydes.All the complexes are isostructurally tetranuclear Zn(Ⅱ) complexes,containing endogenous alkoxo and phenoxo bridges.Applications of the macrocyclic ligands as Zn2+ sensors have been investigated.Take H4L1 for example,it exhibits a 4-fold fluorescence enhancement upon the addition of 2 equiv.of Zn2+ in MeOH.  相似文献   

4.
《Polyhedron》1999,18(23):3013-3018
The reaction of 3,14-dimethyl-2,6,13,17-tetraazatricyclo[14,4,01.18,07.12]docosane (L1) with bromoacetic acid produced the macrocycle (L2=2,13-bis(2-carboxymethyl)-3,14-dimethyl-2,6,13,17-tetraazatricyclo[14,4,01.18,07.12]docosane) in which two carboxymethyl groups are appended. The complexes [NiL2]·4H2O (2) and [CuL2]·4H2O (3) have been prepared and characterized. The two pendant carboxymethyl groups of the macrocyclic ligand are trans to each other, and the absolute configuration is a trans-III in the solid state. The crystal structures of 2 and 3 revealed an axially elongated octahedral geometry with four nitrogen atoms of the macrocycle and two oxygen atoms of the pendant arms at the axial positions. The nickel(II) and copper(II) ions are located at an inversion center. Macrocycle L2 reacts more rapidly with metal (II) ions than does L1. Spectra and electrochemical behaviors of the complexes are also discussed.  相似文献   

5.
The rational selection of ligands is vitally important in the construction of coordination complexes. Two novel ZnII complexes, namely bis(acetato‐κO)bis[1‐(1H‐benzotriazol‐1‐ylmethyl)‐2‐propyl‐1H‐imidazole‐κN3]zinc(II) monohydrate, [Zn(C13H15N5)2(C2H3O2)2]·H2O, ( 1 ), and bis(azido‐κN1)bis[1‐(1H‐benzotriazol‐1‐ylmethyl)‐2‐propyl‐1H‐imidazole‐κN3]zinc(II), [Zn(C13H15N5)2(N3)2], ( 2 ), constructed from the asymmetric multidentate imidazole ligand, have been synthesized under mild conditions and characterized by elemental analyses, IR spectroscopy and single‐crystal X‐ray diffraction analysis. Both complexes exhibit a three‐dimensional supramolecular network directed by different intermolecular interactions between discrete mononuclear units. The complexes were also investigated by fluorescence and thermal analyses. The experimental results show that ( 1 ) is a promising fluorescence sensor for detecting Fe3+ ions and ( 2 ) is effective as an accelerator of the thermal decomposition of ammonium perchlorate.  相似文献   

6.
Two new isomorphous tetranuclear complexes [Cu4L2(4,4′-bipy)2]·(ClO4)4·2CH3CN·2H2O (1) and [Zn4L2(4,4′-bipy)2]·(ClO4)3·CH3O·4H2O (2) have been obtained and fully characterized (where bipy = bipyridine, H2L = macrocycle is the [2+2] condensation product of 2,6-diformyl-4-fluoro-phenol and 1,4-diaminobutane). They exhibit wheel-like configuration in which two 4,4′-bipy molecules connect two dinuclear [M2L]2+ units. The interactions of the complexes with calf thymus DNA were studied by UV-Vis and CD spectroscopic techniques. The binding constants of 1 and 2 are 2.27 × 106 and 3.89 × 105 M−1, respectively. The magnetic measurement of 1 reveals that there are strong antiferromagnetic coupling (J = -272.6 cm−1) between two Cu(II) ions in the macrocyclic unit and ferromagnetic interaction (j′ = 41.7) between the Cu(II) ions in two adjacent macrocyclic units. Furthermore, the cyclic voltammogram of 1 shows that it undergoes two quasi-reversible processes with the half wave potentials -0.232 and -0.606 V, respectively.  相似文献   

7.
The reaction of 1,8-diamino-3,6-diazaoctane and diethyl malonate in dry methanol yielded a 13-membered macrocycle. Complexes of the type [Ln(tatd)Cl2 (H2O)3]Cl [LnIII=La, Pr, Nd, Sm, Eu, Gd, Tb, Dy; tatd=1, 5, 8, 11-tetra-azacyclotridecane-2,4-dione] have been synthesized by template condensation. The complex [La(tatd)Cl2 (H2O)3]Cl in methanol was reacted with lanthanide chlorides to yield the trinuclear complexes of type [2{La(tatd)Cl2(H2O)3}LnCl3]Cl2 [LnIII=La, Pr, Nd, Sm, Eu, Gd, Tb, Dy]. The chemical compositions of mono and trinuclear complexes have been established on the basis of analytical, molar conductance, electrospray (ES) and fast atom bombardment (FAB) mass data. In mononuclear complexes the Ln3+ ion is encapsulated by four ring nitrogens and in trimetallic complexes the exo-carbonyl oxygens of two mononuclear units coordinate to the Ln3+ ions resulting in a polyhedron around the lanthanide ions. Thus the macrocycle is bonded in a tetradentate fashion in the former complexes and hexadentate in the latter. The coordination number nine around the encapsulated Ln3+ and seven around the exo-oxygen bonded Ln3+ ions are established. The symmetry of the ligand field around the metal ions is indicated from the emission spectra.  相似文献   

8.
The novel phenol and phthalazine-based symmetric compartmental 26-membered polyaza macropolycyclic ligand LH2, was synthesised, incorporating 2,6-diformyl-p-cresol and 1,4-dihydrazinophthalazine via 1:1 condensation. Its coordination behaviour with CuII and ZnII ions was investigated. The tetranuclear complexes [M4μ(Cl2)(L)Cl4]·2H2O exhibited aremarkably high stability, suggesting that, along with the large number of nitrogen donors available for metal binding, deprotonated phenolic functions were also involved in binding the metal ion. Incorporation of the bridging units into the macrocyclic cavity influenced electronic communications between the metal ions.  相似文献   

9.
Two porous metal–organic frameworks (MOFs), [Zn3(L)(H2O)2] ? 3 DMF ? 7 H2O ( MOF‐1 ) and [(CH3)2NH2]6[Ni3(L)2(H2O)6] ? 3 DMF ? 15 H2O ( MOF‐2 ), were synthesized solvothermally (H6L=1,2,3,4,5,6‐hexakis(3‐carboxyphenyloxymethylene)benzene). In MOF ‐ 1 , neighboring ZnII trimers are linked by the backbones of L ligands to form a fascinating 3D six‐connected framework with the point symbol (412.63) (412.63). In MOF‐2 , eight L ligands bridge six NiII atoms to generate a rhombic‐dodecahedral [Ni6L8] cage. Each cage is surrounded by eight adjacent ones through sharing of carboxylate groups to yield an unusual 3D porous framework. Encapsulation of LnIII cations for tunable luminescence and small drug molecules for efficient delivery were investigated in detail for MOF‐1 .  相似文献   

10.
Two heterobimetallic Zn‐Nd phenylene‐bridged Schiff‐base ligands complexes [ZnNd L1 (Py)(NO3)3] ( 1 ) and [Zn L2 Nd(Py)(NO3)3]·MeCN ( 2 ) (Py = pyridine, H2L1 = N,N′‐bis‐ (3‐methoxy‐salicylidene)phenylene‐1,2‐diamine, H2L2 = N,N′‐bis‐5‐bromo‐3‐methoxy‐salicylidene)phenylene‐1,2‐diamine) were obtained. Both 1 and 2 were structurally characterized by X‐ray crystallography, and their near‐infrared (NIR) luminescent properties were determined. For the two complexes, the occupation of pyridine at the axial position of 3d Zn2+ ions could effectively prevent luminescent quenching arising from OH‐, NH‐ or CH oscillators of the solvates around the 4f Nd3+ ions, and the heavy‐atom (Br) effect of the Schiff‐base ligands on their NIR luminescent properties is also discussed.  相似文献   

11.
In this work, we present the synthesis and optical study of the binuclear zinc(II) macrocyclic complexes, derived from 4-methyl-2,6-diformylphenol and 1,2-diaminobenzene (H2L). Two zinc macrocyclic complexes with different anions were prepared and characterized: [Zn2LCl2]·H2O (1) and [Zn2L](NO3)2 (2).  相似文献   

12.
A series of heterometallic 3d–Gd3+ complexes based on a lanthanide metalloligand, [M(H2O)6][Gd(oda)3] ? 3 H2O [M=Cr3+ ( 1‐Cr )] (H2oda=2,2′‐oxydiacetic acid), [M(H2O)6][MGd(oda)3]2 ? 3 H2O [M=Mn2+ ( 2‐Mn ), Fe2+ ( 2‐Fe ) and Co2+ ( 2‐Co )], and [M3Gd2(oda)6(H2O)6] ? 12 H2O [M=Ni2+ ( 3‐Ni ), Cu2+ ( 3‐Cu ), and Zn2+ ( 3‐Zn )], are reported. Magnetic and heat‐capacity studies revealed a significant impact on the magnetocaloric effect depending on the anisotropy of the 3d transition metal ions, as confirmed by comparison of the observed maximum values of ?ΔSm between complexes 2‐Co and 1‐Cr . In these two complexes, the 3d metal ions have the same spin (S=3/2 for Co2+ and Cr3+ ions), and the theoretical calculation suggested a larger ?ΔSm value for 2‐Co (47.8 J K?1 kg?1) than 1‐Cr (37.5 J K?1 kg?1); however, the significant anisotropy of Co2+ ions in 2‐Co , which can result in smaller effective spins, gives a smaller value of ?ΔSm for 2‐Co (32.2 J K?1 kg?1) than for 1‐Cr (35.4 J K?1 kg?1) at ΔH=9 T.  相似文献   

13.
Two mixed‐metal‐center inorganic‐organic hybrid frameworks incorporating N‐(Phosphonomethyl)iminodiacetate(H4pmida), [Zn2V2O2(pmida)2(H2O)10]·H2O ( 1 ) and [Zn2V2O2(pmida)2(H2O)12]·2H2O ( 2 ), were synthesized by hydrothermal reactions and characterized by elemental analysis, IR spectra, UV‐Vis spectra and single crystal X‐ray analysis. In complex 1 , the centrosymmetric dimeric [V2O2(pmida)2]4– unit connected to neighboring Zn2+ through the phosphonate group, while 2 the [V2O2(pmida)2]4– unit uncoordinated with the Zn2+ in the presence of NaOH. Magnetic measurements in the range 2‐300 K have shown weak antiferromagnetic interaction between the adjacent vanadium ions in complexes.  相似文献   

14.
Two complexes based on the ligand 1,4‐dihydro‐2,3‐quinoxalinedione, namely [Mn(H2L)2(H2O)2]n ( 1 ) and {[Zn2(H2L)2(tz)2] · 5H2O}n ( 2 ) (H3L = 2,3‐dioxo‐1,2,3,4‐tetrahydroquinoxaline‐6‐carboxylic acid, Htz = 1,2,4‐triazole) were hydrothermally synthesized and characterized by elemental analyses, IR spectroscopy, as well as single‐crystal and powder X‐ray diffraction. Complex 1 exhibited a 1D comb‐like chain formed by H2L anions linking MnII ions, whereas complex 2 was a 2D layer‐like structure with square‐shaped windows and outstretched arms built by combination of H2L and tz ligands with ZnII ions. The adjacent chains or layers connected with each other by intermolecular hydrogen bonding and π–π stacking to further extend to a 3D supermolecular framework. In addition, the thermal stabilities, luminescence properties, and optical energy gap of 1 and 2 were investigated in detail.  相似文献   

15.
We report a macrocyclic ligand based on a 3,6,10,13‐tetraaza‐1,8(2,6)‐dipyridinacyclotetradecaphane platform containing four hydroxyethyl pendant arms (L1) that forms extraordinary inert complexes with Ln3+ ions. The [EuL1]3+ complex does not undergo dissociation in 1 M HCl over a period of months at room temperature. Furthermore, high concentrations of phosphate and Zn2+ ions at room temperature do not provoke metal‐complex dissociation. The X‐ray crystal structures of six Ln3+ complexes reveal ten coordination of the ligand to the metal ions through the six nitrogen atoms of the macrocycle and the four oxygen atoms of the hydroxyethyl pendant arms. The analysis of the Yb3+‐ and Pr3+‐induced paramagnetic 1H NMR shifts show that the solid‐state structures are retained in aqueous solution. The intensity of the 1H NMR signal of bulk water can be modulated by saturation of the signals of the hydroxy protons of Pr3+, Eu3+, and Yb3+ complexes following chemical‐exchange saturation transfer (CEST). The ability of these complexes to provide large CEST effects at 25 and 37 °C and pH 7.4 was confirmed by using CEST magnetic resonance imaging experiments.  相似文献   

16.
Acrylamide complexes of metal nitrates: [M(O‐OC(NH2)CHCH2)n(H2O)m][NO3]2 (M = Co( 1 ), Ni( 2 ) (n = 6 and m = 0) and Zn( 3 ) (n = 4 and m = 2)) have been determined by using single crystal X‐ray diffraction analysis. All complexes crystallize in the triclinic space group . The structures of 1 and 2 represent octahedral species [M(AAm)6]2+ (AAm = O‐OC(NH2)CHCH2 and M = Co or Ni) and uncoordinated nitrate ions. The structure of 3 involves the octahedral cation [Zn(AAm)4(H2O)2]2+ in which the Zn2+ environment includes oxygen atoms of four acrylamide and two water molecules that are stabilized using ionic nitrate ions. The observations of the solid‐state IR spectroscopic vibrational frequencies of these acrylamide complexes are in agreement with the crystal structures.  相似文献   

17.
The isomorphous title complexes, dichlorido[4‐(3,5‐dimethyl‐4H‐1,2,4‐triazol‐4‐yl)benzoic acid‐κN1]zinc(II) dihydrate, [ZnCl2(C11H11N3O2)2]·2H2O, and dibromido[4‐(3,5‐dimethyl‐4H‐1,2,4‐triazol‐4‐yl)benzoic acid‐κN1]zinc(II) dihydrate, [ZnBr2(C11H11N3O2)2]·2H2O, were synthesized and crystallized by slow evaporation of the solvent from a solution of the ligand and either zinc chloride or zinc bromide, respectively, in water/ethanol. The ZnII ions occupy twofold axes in the noncentrosymmetric orthorhombic space group Fdd2. The metal ion is approximately tetrahedrally coordinated by two monodentate triazole groups of the ligands and additionally by two halide ions. The water molecules incorporate the complexes into a three‐dimensional framework made up by hydrogen bonds. Furthermore, each complex possesses two hydrogen‐bond‐donor sites represented by the carboxy groups and two acceptor sites at the noncoordinating N atoms of the triazoles.  相似文献   

18.
A new porous solid macrocyclic 1,4,7,10,14,17,20‐heptaazadocosane‐3,21‐dione polysiloxane ligand system of the general formula P‐(CH2)3‐C15H32O2N5, (where P represents [Si‐O]n siloxane network) has been prepared by the reaction of immobilized iminobis(N‐diethylenediamineacetamide)polysiloxane with 1,3 dibromopropane. The new macrocyclic polysiloxane ligand system exhibits high potential for the uptake of metal ions (Fe3+, Co2+, Ni2+, Cu2+ and Zn2+). Complexation with copper ions exhibits a high selectivity in which two copper ions were involved per one macrocyclic ligand group.  相似文献   

19.
The coordination polymers (CPs), [Ni(L)(H2O)4]n ( 1 ), [Co(HL)2(H2O)2]n ( 2 ), {[Cu(L)(H2O)3] · H2O}n ( 3 ), [Mn(L)(H2O)2]n ( 4 ), [Cd(L)(H2O)2]n ( 5 ), and {[Zn2(L)2] · H2O}n ( 6 ), were solvothermally synthesized by employing the imidazol‐carboxyl bifunctional ligand 4‐(1H‐imidazol‐1‐yl) phthalic acid (H2L). Single‐crystal X‐ray diffraction indicated that the L2–/HL ligands display various coordination modes with different metal ions in 1 – 6 . Complexes 1 and 2 show one‐dimensional (1D) chain structures, whereas complexes 3 – 6 show 2D layered structures. The magnetic properties of these complexes were investigated. Complexes 1 and 3 indicate weak ferromagnetic interactions, whereas complexes 2 and 4 demonstrate antiferromagnetic interactions. In addition, luminescence properties of 5 and 6 were measured and studied in detail.  相似文献   

20.
The bifunctional ligand 2,6‐dipicolinoylbis(N,N‐diethylthiourea) (H2L) readily reacts with mixtures of Zn(CH3COO)2 and LnCl3 in MeOH at ambient temperature with formation of trinuclear heterobimetallic complexes [Zn2Ln(L)2(OAc)3] ( 1a – 1f ) (Ln = Ce, Nd, Sm, Gd, Dy, Er). The X‐ray single‐crystal diffraction and structural studies of the complexes revealed their isostructural nature, in which two doubly‐charged ligands {L2–} bind two Zn2+ ions with the terminal acylthiourea sites and one Ln3+ ion with the central 2,6‐pyridinedicarboxamide site. In the complexes, the coordination numbers of LnIII and ZnII ions are 9 and 5, respectively. Magnetic properties of the complexes were studied by temperature‐dependent dc magnetic measurements. The observed μeff values at room temperature are all closed to the calculated values. Fitting χM and M data of [Zn2Gd(L)2(OAc)3] ( 1d ) shows a giso value of 1.94.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号