Synthesis,Crystal Structure and Fluorescence Properties of a 3D Framework Based on Hexanuclear Lanthanum 5-Nitroisophthalate Entities

摘要

The reaction of lanthanum（Ⅲ） nitrate and 5-nitroisophthalic acid in isopropanol/H2O under hydrothermal conditions leads to a 3D lanthanum-containing coordination polymer with the general chemical formula {[La6（Nip）9（H2O）4 ]·（H2O）4 }∞（1,Nip=5-nitroisophthalate）.The single-crystal X-ray analyses show that this compound crystallizes in the orthorhombic system,space group Ima2 with a=9.7769（12）,b=28.239（3）,c=21.149（2）,V=5839.1（11）3,Z=2,Mr=2859.61,Dc =1.626 g/cm 3,F（000）=2752.14040 reflections are collected,of which 5275 are unique （R int=0.0241）.Final GOOF=1.083,R=0.0406 and wR=0.1182,R indices based on 5183 reflections with I〉2σ（I）（refinement on F2）,443 parameters,1 restraint.Lp and absorption corrections were applied,=2.242mm-1.Absolute structure parameter x=0.08（3）.The crystal structure can be described as the butterfly-liked hexanuclear lanthanum entities {La6O6（CO2）8 } covalently linked to each other by nitroisophthalate ligands into an intricate three-dimensional structure.The fluorescence spectroscopy of compound 1 has been investigated.