Synthesis, Crystal Structures, DNA Cleavage and DNA-binding Studies of Ho(Ⅲ) and Er(Ⅲ)Complexes Based on Macrocyclic Schiff Base

Two novel macrocyclic Schiff base complexes[LnL(PhCOO)(CH3OH)](ClO4)2·(CH3OH)2(Ln=Ho,1;Ln=Er,2),in which L denotes the macrocyclic ligand,were synthesized via condensation of 2,6-diformyl-4-methyl-phenol and 1,3-diamino-2-propanol by employing benzoate as the second ligand.Their crystal structures were determined by X-ray diffraction,which showed that both complexes belong to a monoclinic system with space group P21/c.The coordination polyhedron displayed a distorted bicapped trigonal prism with the coordination number of eight.Both complexes efficiently cleaved supercoiled DNA to its nicked circular form.The UV-vis absorption results and ethidium bromide(EB)fluorescence spectra indicated that the complexes bind to CT-DNA in an intercalative mode,with Ksq values to be 11830 and 10560,respectively.

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 Schiff Base Type Macrocycles Containing Naphthalene Ring

A series of new Schiff base type macrocyclic crown ethers containing naphthalene ring were synthesized from 2,2'-di(o-formylnaphthoxy) ethyl ether or 1,2-di(o-formylnaphthoxy) ethane and four appropriate diamines. The chemical structures of the new compounds were characterized by elemental analysis, infrared spectra, nuclear magnetic resonance spectra and mass spectrometry.

Synthesis and Electrical Conductivities of Fully Conjugated Schiff Base Macrocycles Containing 1,3,4-Oxadiazole

Conjugated Schiff base macrocycles containing 1,3,3-oxadiazole were prepared by [2 + 2] cyclic condensation of phenylenediamine with 2,5-bis(m-formyl-phenyl)-1,3,4-oxadiazole. These macrocycles with iodine or TCNQ produced stable charge-transfer complexes. The formation of complexes were identified by UV-Vis and FT-IR spectra.

Synthesis and spectral studies of macrocyclic Pb(Ⅱ),Zn(Ⅱ),Cd(Ⅱ)and La(Ⅲ) complexes derived from 1,4-bis(3-aminopropoxy)butane with metal nitrate and salicylaldehyde derivatives

Eight new macrocyclic complexes were synthesized by template reaction of 1,4-bis（3-aminopropoxy）butane with metal nitrate and 1,3-bis（2-formylphenyl）propane or 1,4-bis（2-formylphenyl）butane and their structures were proposed on the basis of elemental analysis, FTIR, UV-vis, molar conductivity measurements, ^1H NMR and mass spectra. The metals to ligand molar ratios of the complexes were found to be 1： 1. The complexes are 1：2 electrolytes for Pb（II）, Zn（II） and Cd（II） complexes and 1：3 electrolytes for La（III） as shown by their molar conductivities （Am） in DMSO at 10^-3 mol L^-1. Due to the existence of free ions in these complexes, such complexes are electrically conductive. The configurations of La（III） and Pb（II） were proposed to probably octahedral and Zn（II） and Cd（II） complexes were proposed to probably tetrahedral.

Synthesis and characterization of new azo containing Schiff base macrocycle

Fully conjugated Schiff base macrocycle has been prepared through a simple and mild condition,a one-pot cyclization procedure of four-component without using a template.The condensation reaction of related bis（hydroxybenzaldehyde） with phenylenediamines to prepare a conjugated[2 ＋ 2]Schiff base macrocycle has been investigated and fluorescent[2 ＋ 2]Schiff base macrocycles with N_2O_2 binding pockets has been prepared and characterized by elemental analysis,^1H NMR,IR,fluorescent,UV-visible and MALDI mass spectroscopies.

One-pot synthesis of [1+1] and 62-membered [2+2] Schiff base macrocycles

New [1＋1] and 62-membered [2＋2] Schiff base macrocycles containing a 2,6-diamidopyridine subunit have been synthesized by condensation reaction of the precursors pyridine-2,6-dicarboxamide and 1,10- bis（2＇-formylphenyloxy）decane in the presence of phosphoric acid via a one-pot process. The cyclo- condensed products were effectively isolated by gel column chromatography and characterized by 1H NMR, FTIR, mass spectrometry and X-ray analysis. The two macrocycles have a twisted structure, and not an open ＇circular＇ conformation in the solid state.

Synthesis and crystal structure of Ni,Cu complexes of 5-methyl-10,10,15,15,20,20-hexaethylcalix[4]pyrrole mono-Schiff bases

The functionalized calix[4]pyrrole meso-substituted Schiff bases were conveniently prepared by four- step synthetic route. Furthermore, the nickel and copper complexes of calix[4]pyrrole meso-substituted Schiff base with 1：2 stoichiometry were obtained. The crystal structures of the calix[4]pyrroles and their metal complexes were determined by X-ray diffraction.

Synthesis and Characterization of New Macrocyclic Cu（Ⅱ） Complexes from Various Diamines, Copper（Ⅱ） Nitrate and 1,4-Bis（2-formylphenoxy）butane

Six new macrocyclic complexes were synthesized by a template reaction of 1,4-bis（2-formylphenoxy）butane with diamines and Cu（NO3）2·3H2O and their structures were proposed on the basis of elemental analysis, FT-IR, UV-Vis, magnetic susceptibility measurements, molar conductivity measurements and mass spectra. The metal to ligand molar ratios of the Cu（Ⅱ） complexes were found to be 1 ： 1. The Cu（Ⅱ） complexes are 1 ： 2 electrolytes as shown by their molar conductivities （∧m） in DMF at 10^-3 mol·L^-1. Due to the existence of free ions the Cu（Ⅱ） complexes are electrically conductive. Their configurations were proposed to be probably distorted octahedral.

Synthesis and characterization of macrocyclic compounds with a hydroxyl functional group

A novel [1＋1] Schiff-base macrocyclic compound 3 has been synthesized from precursor 1, 1,3-bis（2＇- formylphenoxy）-2-propanol, and precursor 2, resorcinol-bis（4-aminophenyl）ether, via condensation and cyclizaction using Ba2＋ as template. The macrocycle 3 was further reduced giving saturated macrocycle 4. The structures of 3 and 4 were characterized by elemental analysis, ~H NMR, IR, and MS spectra, and their structures were determined via single crystal X-ray diffraction studies. X-ray diffraction analysis revealed that the macrocyclic compound 3 has a folded conformation, and the corresponding reduced product 4 adopts a twisted and folded conformation due to its flexible nature. ~ 2013 Bi-Xue Zhu. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.