Design,Synthesis And Properties Of Functionalized Nitronyl Nitroxide Radicals And Their Metal-Complexes

In recent decades,in order to meet the current high-tech requirements for magnetic materials,researchers have designed different synthetic routes to obtain nitroxide radicals with different coordination abilities and complexes with different spatial structures.In this paper,eight functional nitroxide radical ligands and fourteen metal ion-nitroxide radical complexes were synthesized by design.They were characterized by using X-ray single crystal diffraction,X-ray powder diffraction,infrared,thermogravimetry,and the magnetism of some complexes was studied.The main research contents of this paper are as follows:1.Eight kinds of nitroxide radicals were synthesized.They are m-pyridyl-o-methoxyphenyl nitroxide radical(NIT-o-PhO-3Py),m-pyridyl-/m-methoxyphenyl nitroxide radical(NIT-m-PhO-3Py),m-pyridyl-p-methoxyphenyl nitroxide radical(NIT-p-PhO-3Py),p-pyridyl-m-methoxyphenyl nitroxide radical(NIT-m-PhO-4Py),p-pyridyl-o-methoxyphenyl nitroxide radical(NIT-o-PhO-4Py),p-carboxyphenyl nitroxide radical(NIT-p-PhCOOH)m-hydroxyphenyl nitroxide radical(NIT-m-PhOH),and p-pyridyl nitroxide radical(NIT-p-Py).2.The complex[Cu(hfac)2(NIT-o-PhO-3Py)]2(1)was synthesized with m-pyridyl-o-methoxyphenyl nitroxide radical(NIT-o-PhO-3Py)as ligand;the complex {[Cu(hfac)2]3(NIT-m-PhO-3Py)2}n(2)was synthesized with m-pyridyl-m-methoxyphenyl nitroxide radical(NIT-m-PhO-3Py)as ligand;the complex[Cu(hfac)2]3(NIT-p-PhCOOH)2(3)was synthesized with p-carboxyphenyl nitroxide radical(NIT-p-PhCOOH)as ligand;the complex[Cu(hfac)2(NIT-m-PhOH)]n(4)was synthesized with m-hydroxyphenyl nitroxide radical(NIT-m-PhOH)as ligand;the complex[Co(hfac)2(NIT-m-PhO-4Py)]2(5)was synthesized with p-pyridyl-m-methoxyphenyl nitroxide radical(NIT-m-PhO-4Py)as ligand;the complex[Co(hfac)2(NIT-p-PhO-3Py)]2(6)was synthesized with m-pyridyl-p-methoxyphenyl nitroxide radical(NIT-p-PhO-3Py)as ligand.Using p-pyridyl-o-methoxyphenyl nitroxy radical(NIT-o-PhO-4Py)as ligand,four complexes were synthesized:[Co(hfac)2(NIT-o-PhO-4Py)]2(7),[Ni(hfac)2(NIT-o-PhO-4Py)]2(8),[Cu(hfac)2]5(NIT-o-PhO-4Py)4(9)and[Cu(hfac)2(NIT-o-PhO-4Py)]n(10).The co-ligands were hexafluoroacetylacetone.The magnetic properties of complexes(1)-(3)and(7)were studied,and the results showed that complex(1)has weak ferromagnetic interaction;complex(2)has weak antiferromagnetic interaction;complexes(3)and(7)exhibit strong antiferromagnetic interactions.3.Four complexes:[Ln(hfac)3(NIT-p-Py)]2(Ln=Gd(11),Tb(12).Dy(13))and[La(hfac)3(NIT-p-Py)·H2O]2(14)were synthesized by the reaction of p-pyridyl nitroxide radical(NIT-p-Py)with hexafluoroacetylacetone salt of rare earth metals.The magnetic property of the complex(12)was studied and the result showed that the complex(12)has a strong antiferromagnetic interaction.In conclusion,fourteen novel metal-nitroxide radical complexes were assembled with metal salts by using the newly synthesized nitroxide radical.Among them,complexes(1).(5)-(8)and(11)-(14)are cyclic complexes.Complex(2)is two cyclic dimers connected by Cu ions.Connected and extended infinitely to form a one-dimensional chain structure.Moreover,the complexes(1)and(2)show essential differences in the structure and magnetic properties due to the subtle differences in the radical substituents.This study broadens the research field of cyclic complexes,proves that the subtle differences of free radicals bring great changes to the structure and properties of complexes,enriches the research contents of 2p-3d and 2p-4f series complexes,and provides a scientific basis for the construction of more new molecular magnetic materials with diverse structures and excellent properties.