Synthesis, Characterization Of Several Aza-crown Ethers, Nitrogen-pivot-lariat Crown Ethers And Their Complexes

The coordination complexes of rare earth with macro cyclic ligand have distinctive structure and properties, and potential application in exploring new materials, the investigation of analysis and separation of the ions. In order to investigate the coordinating properties of different macro cyclic ligand with rare earth ions, and the influence of substituent group of the ligand to their rare earth complexes' fluorescence properties, this paper reports the synthesis of eight nitrogen-pivot benzo-aza-lariat crown ethers (L¹:1,22-diacetyl-1,22-diaza-3,6:14,17-dibenzo-7,10,13,16,25-pentaoxa-cyclotetracosane; L²:1,22-dibenzoyl-1,22-diaza-3,6:14,17-dibenzo-7,10,13,16,25-pentaoxa-cyclotetracosane;L³:1,22-di(2-carboxyl-benzoyl)-1,22-diaza-3,6:14,17-dibenzo-7,10, 13,16,25-pentaoxa-cyclotetracosane; L⁴:1,22-di(3-carboxyl-propionyl)-1,22-diaza-3,6:14,17-dibenzo-7,10,13,16,25-pentaoxa-cyclotetracosane; L⁵:1,22,25-triacetyl-1,22,25-triaza-3,6:17,20-dibenzo-7,10,13,16-tetraoxa-cycloheptacosane; L⁶:1,22,25-tribenzoyl-1,22,25-triiaza-3,6:14,17-dibenzo-7,10,13,16-tetraoxa-cyclotetracosane;L⁷:1,22,25-tri(2-carboxyl-benzoyl)-1,22,25-triaza-3,6:14,17-dibenzo-7,10,13,16-tetraoxa-cyclote-tracosane;L⁸:1,22,25-tri(3-carboxyl-propionyl)-1, 22,25-triaza-3,6:14,17-dibenzo-7,10,13,16-tetraoxa-cyclotetracosane ) and their rare earth complexes through elemental analysis, molar conductance, IR spectra and thermo gravimetric analysis.From the data we get, it can be seen that all nitrogen-pivot benzo-aza-lariat crown ether ligands have good coordinating properties with rare earth ions. For the installed acyl in the ring, which decrease electronic cloudy density around nitrogen atoms, and it also change the spatial structure of ligand, thus nitrogen atoms not take part in coordinate with rare earth ions, and only stop oxygen and oxygen atoms in the acyl act as donator atoms.The data of fluorescence spectra indicates that complexes of these ligands with Eu (III), Tb (III) all show characteristic line emission of rare earth ions. The complexes of L6 show higher luminescence intensity than others. At the same time, we determine the triplet state of the ligands, study the rule that control the change of their fluorescence properties in a deep step.The complexes of quinolin and its derivates have recently received considerable attention due to their potential applications in electroluminescence (EL). But compounds of the crown ethers contain quinolyl have not been reported. For this reason, we design and synthesize two novel quino-aza-crown ethers: L⁹:1, 22-diaza-3,6:17,20-diquino-7,10,13,16,25-pentaoxa-cyclotetra-cos-ane,L¹⁰:1,22,25-triaza-3,6:17,20-diquino-7,10,13,16-tetraoxa-cyclotetracosane.Thecomplexe s of Zn(II) and Al(III) of L⁹ and L¹⁰ are synthesized too. The ligands and complexes are characterized by elemental analysis, molar conductance, and IR spectra analysis. The data of fluorescence spectra indicates thatλ_em of the complexes of the novel quino-aza-crown ethers are red shift. It can be attributed to the electron absorbing of crown ring makes the HOMO-LUMO energy gap decreasing.