The Synthesis of New Sulfur-containing Chiral Macrocyclic Ligands

Five new chiral sulfur-containing macrocyclic ligands which can be used in chiral recognition to guests have been synthesized and characterized

Intramolecular Hydrogen Bond Self-template Synthesis of Some New Robson-type Macrocyclic Ligands

The intramolecular hydrogen bond self-template effect was suggested in the process of directly synthesizing the first six chiral metal-free Robson-type macrocyclic ligands. These ligands were characterized by H-1 NMR, IR, FAB-MS.

Slow magnetic relaxation and photoluminescence behaviors of dilanthanide complexes bearing N_(8)O_(2)donor macrocyclic ligand

On account of the complicated magnetic exchange interactions between lanthanide ions,binuclear lanthanide complexes have broad application prospect in the field of single-molecule magnets.Therefore,it is necessary to develop reasonable bridging ligands to manipulate the directional assembly of binuclear lanthanide complexes.Herein,we selected the macrocyclic ligand L^(N_(8)O_(2))to build up two new dilanthanide complexes[Ln_(2)(LN_(8)O_(2))(OpyO)_(2)(H_(2)O)2](NO_(3))_(2)(1-Ln,Ln=Dy,Tb;LN_(8)O_(2)=hexamethyl-tetraaza-dioxe-dipyrazolacycloicosaphane-2,9,12,19-tetraene;OpyOH=2-pyridinol-1-oxide).Dynamic magnetic studies show that 1-Dy exhibits slow relaxation behavior under a 1 kOe applied field.Further fitting analysis of relaxation times gives the effective energy barrier of 38.2 cm^(−1),and reveals that the slow magnetic relaxation behavior is dominated by the Orbach and Raman processes.High-resolution luminescence emission spectrum indicates the energy gap of 36.8 cm^(−1)between the ground state and the first excited state,consistent with the magnetic measurement results.1-Tb exhibits brilliant characteristic green light emission under UV light excitation.The absolute quantum yield of 1-Tb is 44.8%,and its first-order fitted decay lifetime is 779.21μs at room temperature.This study provides the way for directional construction of high-performance molecular materials with magnetic and optical dual-function.

The Determination of the Protonation Constants of A New Macrocyclic Dinucleating Ligand, BDBPH

The protonation constants of a new dinucleating 24-membered hexaazadiphenol macrocyclic ligand, BDBPH, were determined by potentiometric measurement at 25.0 degreesC and mu = 0.100 mol.L-1 (KCl). The species distributions of the deprotonated and protonated compounds in the pH range from 2 to 12 aqueous solutions were also described.

The Synthesis of a New Macrocyclic Dinucleating Ligand,3,6,9,17,20,23-Hexaaza-29,30-Dihydroxy-13,27-Dimethyl-Tricyclo[23,3,1,1^(11,15)]Triaconta-1(28),11,13, 15(30),25,26-Hexaene

A new dinucleating 24-membered hexaazadiphenol macrocyclic ligand, 3,6,9,17,20, 23-hexaaza-29,30- dihydroxy-13,27-dimethyl-tricycl [23, 3, 1, 1 11,15] triaconta -1(28), 11,13,15(30),25, 26-hexaene, BDBPH, was synthesized by the NaBH4 reduction of the Schiff-base obtained from the [2+2] condensation between diethylenetriamine and diformyl -p-cresol. The structure was characterized by elemental analysis, 1HNMR and FAB-MS. The synthetic method was also discussed.

Syntheses and Crystal Structures of Lanthanide Complexes of New 15-Membered Macrocyclic Ligands with Three Pendant Acetato Groups

Two new 15-membered functionalized macrocycles, dioxo^polyazacycloalkanes with three pendant acetato groups, have been synthesized by the condensation reaction of DTPA dianhydride (DTPA=diethylenetriaminepentaacetic acid) with 1,2-diaminopropane, (15-DTPA-1,2-pn), or 1,2-diaminocyclohexane, (15-DTPA-1,2-cy). Their lanthanide complexes [Ln(15-DTPA-1,2-pn)(H 2O)] 2 [Ln=Eu (1), Gd (2)] and [Ln(15-DTPA-1,2-cy)(H 2O)] 2 [Ln=Eu (3), Gd (4)] were also prepared. Single crystal X-ray diffraction analyses of complexes 2 and 4 show that they have dimeric structures in solid state; each metal ion is nine-coordinated in a distorted tricapped-trigonal prism. In complex 4, the coexistence of two diastereoisomeric molecules in the crystal lattice was observed.

Synthesis of a novel macrocyclic ligand containing bipyridine units

The 6-hydroxymethyl-6'-tetrahydropyranyloxymethyl-2, 2'-bipyridine (2) was synthesized by the reaction of 6,6'-dihydroxymethyl-2, 2'-bipyridine (1) with 3, 4-dihydroxypyran (DHP). 6.Tetrahydropyranyloxymethyl-6'-iodomethyl-2, 2'-bipyridine (5) was obtained from mesylate and iodizating reaction of compound 2. The coupling of 2 and 5 followed by hydrolysis gave bis(6'-hydroxymethyl-2, 2'-bipyridine-6-methyl) ether (7). The macrocyclic ligand 8 was obtained by treating 7 and 6, 6'-dibromethyl-2, 2'-bipyridine. The synthetic conditions of the intermediate 2 and macocyclic ligand 8 were discussed.

A Novel Cobalt(Ⅲ) Complex with Macrocyclic Triamine Ligand for High Capacity Hydrogen Adsorption

The coordination complex of Co（Ⅲ） based on a macrocyclic triamine ligand 1,4-diacetate-1,4,7-triazacyclodecane （L） has been synthesized and characterized. The metal cation is bonded with three nitrogen atoms and two oxygen atoms of L and one chloride ion to form a distorted octahedral geometry. This complex coordinated with macrocyclic ligand possesses large pore volume that will be contributed to observe high H2 adsorption. With respect to the first-principles electronic structure calculations, the feasibility to store hydrogen in the complex is explored. Indeed, the complex has shown a very high total H2 adsorption of 7.2 wt% （wt% = （weight of adsorbed H2）/（weight of host material））, with a binding energy of 0.03 eV/H2

Syntheses and structures of tetranuclear Zn(Ⅱ) complexes with in situ generated macrocyclic Schiff base ligands:Applications in Zn^(2+) sensing

Three novel Zn（II） complexes,[Zn4L1Cl4]-3H2O（1）,[Zn4L2Cl4]-2DMF（2） and[Zn4L^3Cl4]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 Zn^2＋ sensors have been investigated.Take H4L^1 for example,it exhibits a 4-fold fluorescence enhancement upon the addition of 2 equiv.of Zn^2＋ in MeOH.

Synthesis of a Hexagonal Molecular Nickel-wheel

The macrocyclic ligand c-H2pyN2-O3ane （2） was readily prepared in a diluted condition in THF. The mixture of 2 and Ni（OTf）2 in DMF using Et4NOH as the base source gave a mononuclear square planar complex （Et4N）[Ni（OH）（c-pyNE-O3ane）] （3）. Addition of Fe（OTf）2 into the solution of 3 in DMF instantly generated a hexagonal molecular nickel-wheel 4 in 72% yield. Both 3 and 4 were characterized by X-ray crystallography on a MoKa radiation diffractometer （λ= 0.71073 A）： the crystal of 3 was grown in space group P212121 with a = 12.079（5）, b=15.099（6）, c = 17.299（8） A, V = 3160（2） A3, Z = 4, Dc = 1.369 g/cm3, F（000） = 1384, C33H44N4NiO6, Mr = 651.43, μ= 0.665 cm-1, R = 0.0353, wR = 0.0668 for 4548 observed reflections with I〉 2σ（I）; 4 is in space group P21/n with a = 17.7416（17）, b = 17.5490（17）, c = 29.036（3）A,β = 106.195（2）°, V= 8681.5（14） As, Z = 2, Dc = 1.352 g/cm3, F（000） = 3704, C170H190N22Ni6O40, Mr = 3533.70,μ = 719 cm-1, R = 0.0841 and wR = 0.2339 for 9371 observed reflections with I〉 2σ（I）.

Metal-Ligand Cooperative Effect on Intramolecular Electron Transfer in Macrocycle-Encircled Copper-Oxygen Species

Reproduction of ubiquitous metal-ligand cooperativity in copper-oxygen enzyme mimics is crucial for the comprehension of catalytic mechanisms in coppercontaining enzymes and copper-catalyzed chemical transformations.Here we describe the synthesis and reduction behavior of a series of encapsulated dinuclear copper-oxygen species by systematically altering the size and geometric structure of peripheral macrocyclic ligands.Along with the occurrence of a single-electron reduction,these macrocycleencircled dicopper complexes show distinct electron transfer pathways as a function of differently sized and substituted macrocyclic ligands.Detailed structural characterization and density functional theory calculations reveal that a coupled metal-ligand and bimetallic cooperativity is involved in the singleelectron reductionof hydroxyl-bridged dicopper species within macrocyclic homologue ligands Py[7]Ph[1]and Py[7]Ph[1]-Me.The highly flexible configurations of macrocyclic ligands are conducive to stabilizing copper-oxygen intermediates with different valence states and facilitating an intramolecular electron transfer between macrocyclic ligands and the central copper-oxygen moiety.Correlation of biased electron transfer behaviors of copper-oxygen species with their peripheral macrocyclic ligands provides a new means of tuning redox properties of metal cluster species and opens a broader prospect on the mechanistic study of copper-containing enzymes and copper-catalyzed transformations.

Electrochemical and Spectroscopic Studies on the Interaction between Tetracoordinate Macrocyclic Copper（Ⅱ）, Nickel（Ⅱ） and Cobalt（Ⅲ） Complexes with DNA

Mononuclear copper（Ⅱ）, nickel（Ⅱ） and cobalt（Ⅲ） tetracoordinate macrocyclic complexes were synthesized and spectroscopically characterized. The crystal structure of the three compounds were determined by X-ray crystallography. The electrochemical experimental results indicate that the three complexes could interact with DNA mainly by electrostatic interaction. The interaction of tetracoordinate macrocyclic cobalt（Ⅲ） complex with DNA was studied by cyclic voltammetry and UV-vis spectroscopy. The experimental results reveal that tetracoordinate macrocyc- lic cobalt（Ⅲ） complex could interact with DNA by electrostatic interaction to form a 1 ： 1 DNA association complex with a binding constant of 7.50 ×10^3 L·mol^-1.

Synthesis, crystal structure and magnetic properties of the binuclear copper (II) complex of a new bis (1, 4, 7,10-tetraazacy-clodoclecane) ligand

A new binucleating macrocyclic ligand 2,6-bis (1,4,7,10-te-traazacyclododecan-10-ylmethyl)methoxy-benzene (L) and its binuclear copper (II) complex, [ Cu2LBr2 ] (ClO4 )2 · 3H2O (1), was prepared and the structure was determined by X-ray crystallography. Complex 1 crystallizes in monoclinic crystal system, P21/n space group with a = 0.8206(3), b = 2.0892(8), c = 2.3053(7) nm, β=95.83(2)°, V = 3.932 nm3, Mr = 1017.57, Z = 4, Dc= 1.692 g/cm3, and R = 0. 0489, Rw= 0.0552 for 6571 observed reflections with I≥2σ (I). Both of the copper(II) centers are coordinated by four amine nitrogen donors of cyclen subunits and a bromide an-ion, and each copper (II) ion is in a square-pyramidal coordination environment. Variable temperature magnetic susceptibility studies indicate that there exists weak intramolecular an-tiferro-magnetic coupling ( - 2J = 2.06 cm-1) between the two copper(n) centers.

Potassium Acetate/18-Crown-6 Pair:Robust and Versatile Catalyst for Synthesis of Polyols from Ring-Opening Copolymerization of Epoxides and Cyclic Anhydrides

Efficient synthesis of polyester polyols with tunable molecular weight and microstructures from cyclic anhydride/epoxide mixtures by taking advantage of chain transfer reaction remains a great challenge,because most of the catalysts exhibit poor tolerance to chain transfer agent(CTA).In this contribution,we demonstrated that potassium acetate(KOAc)and 18-crown-6(18-C-6)combination has great potential in the synthesis of diverse polyester polyols with controllable molecular weight and high-end group fidelity.Com-pared with KOAc,KOAc/18-C-6 pair could induce a much faster chain transfer between the active and dormant chains,and thus produce polyester polyols with narrow and monomodal distribution.In addition,polyester polyols could be efficiently prepared in laboratory by using commercially available cyclic anhydride without further purification(containing about 2%diacid residual as CTA)with an extremely low catalyst loading([catalyst pair]:[anhydride]:[epoxide]=1:50000:250000,[catalyst pair]=0.0004 mol%).KOAc/18-C-6 could also promote the self-switchable copolymerization of cyclic anhydride/epoxide/cyclic ester mixtures.Ring-opening copolymerization of cyclic ester was initiated automatically after the full conversion of cyclic anhydride,finally producing polyester polyols with ABA-type block structure.

Application of Fe^Ⅲ-TAML/H2O_(2) system for treatment of fluoroquinolone antibiotics

Over the recent past,fluoroquinolone antibiotics(FQs)have raised extensive attention due to their potential to induce the formation of resistance genes and"superbugs",thus various advanced oxidation techniques have been developed to eliminate their release into the environment.In the present study,the prototype tetraamido macrocyclic ligand(Fe^Ⅲ-TAML)/hydrogen peroxide(H2O_(2))system is employed to degrade FQs(i.e.,norfloxacin and ciprofloxacin)over a wide p H range(i.e.,p H 6-10),and the reaction rate increases with the increase in p H level.The effect of dosage of Fe^Ⅲ-TAML and H2O_(2) on the degradation of FQs is evaluated,and the reaction rate is linearly correlated with the added amount of chemicals.Moreover,the impact of natural organic matters(NOM)on the removal of FQs is investigated,and the degradation kinetics show that both NOM type and experimental concentration exhibit negligible influence on the oxidative degradation of selected antibiotics.Based on the results of liquid chromatography-high resolution mass spectrometry and theoretical calculations,the reaction sites and pathways of FQs by Fe^Ⅲ-TAML/H2O_(2) system are further predicted and elucidated.

Manganese catalyzed asymmetric transfer hydrogenation of ketones

The asymmetric transfer hydrogenation(ATH)of a wide range of ketones catalyzed by manganese complex as well as chiral P_(x)N_(y)-type ligand under mild conditions was investigated.Using 2-propanol as hydrogen source,various ketones could be enantioselectively hydrogenated by combining cheap,readily available[MnBr(CO)_(5)]with chiral,22-membered macrocyclic ligand(R,R,R',R')-CyP_(2)N_(4)(L_(5))with 2 mol%of catalyst loading,affording highly valuable chiral alcohols with up to 95%ee.