Preparation And Properties Of Metal Complexes Based On Phenoxyisopropionic Acid And Azoles

Three chiral dicarboxylic ligands,namely,（R）-4-（4-（1-carboxyethoxy）phenoxy）-3-fluorobenzoic acid （L¹）,（R）-4-（4-（1-carboxyethoxy）phenoxy）-3-chlorobenzoic acid（L²）,and （R）-4-（4-（1-carboxyethoxy）phenoxy）-3-nitrobenzoic acid（L³）have been synthesized from（R）-（+）-2-（4-Hydroxyphenoxy）propionic acid.With different substituents attached on the benzene ring,the three ligands exhibited similar V-shaped configurations,which are expected to form different coordination polymers with novel structures.Five coordination polymers:[Co（L¹）（bimb）]2·Me OH·H2O（1）,[Co（L²）（bimb）]2·Me OH·H2O（2）,[Co（L³）（bimb）]2·Me OH·H2O（3）,[Zn（L³）（bimb）]2·Me OH·H2O（4）,[Cd（L³）（bimb）]2·Me OH·H2O（5）,,[Ag（L¹）（phen）]（6）,[Ag（L³）（phen）]（7）,[Cu（L¹）（phen）]·2H₂O（8）,[Cu（L3）（phen）]·2H₂O（9）（bimb=4,4’-bis（1H-imidazol-1-yl-methyl）biphenyl,phen=1,10-Phenanthroline monohydrate）are obtained by reacting the three ligands with transition metals in the presence of the second N-donor ligand.Complexes 1-5 are isomorphic with two-dimensional 2-fold interpenetration structures,sharing the following similar structural features:（a）The chiral carboxylate ligands linked the transition metals to form right-handed helical chains,which could induce the chains linked by achiral bimb and metals to show similar right-handed helixes;（b）The interpenetration occurring inside the cavities caused the formation of right-handed DNA-like double helical structures.Besides,their thermal stabilities,circular dichroism spectra,nonlinear optical and catalytic properties are also investigated.The results show that the complexes 1-5 have relatively stable structures and obvious Cotton effect.These complexes also demonstrate second-order nonlinear optical properties and significant asymmetric catalytic activities toward the aldol reactions.Complexes 6-9 demonstrate the asymmetric catalytic activities toward the Henry Reactions.Moreover,we investigated the optical and catalytic properties of complexes 10 and11,which have been synthesized and reported by our research group before.The two complexes are based on metal copper and zinc,namely:[Cu I（4-nptz）（CH3CN）]n（10）,[Zn（4-nbtz）2]n（11）,（4-nptz=5-（4-nitrophenyl）-1H-tetrazole,4-nbtz=5-（4-nitrobenzyl）-1H-tetrazole）.Photoluminescence analysis of complexes 10-11reveals that the luminescent emissions of the ligands could be tuned by the coordinated metal cations.In addition,the complex 10 shows catalytic activity for the coupling reaction ofα-amino acids and bromobenzene under relatively mild conditions.