Homochiral Coordination Polymers Based On Chiral Alanine Derivative Ligands With Different Shapes

In recent years,homochiral coordination polymers(CPs)have attracted wide attention owing to their great potential for applications in heterogeneous catalysis,correspondence analysis,chiral recognition,magnetism,non-linear optical properties and so on.Natural chiral amino acids,which are inexpensive,nontoxic and readily available,have been widely utilized as organic linkers to construct homochiral CPs.Moreover,carboxylic ligands with good coordination ability and flexible coordination manners have contributed to construct CPs with fascinating architectures.This paper can be mainly divided into the following sections:1.Synthesis,characterization and properties of transition metal coordination polymers based on V-shape chiral alanine ligandHerein,two homochiral coordination polymers have been hydro(solvo)thermally synthesized with V-shape chiral alanine ligand(H2L1)and transition metal ions:[Zn(Li)]·3H2O(1),[Cd(Li)](2)(H2L1=2,6-pyridine-diamino-bis(L-alanine)).Single-crystal X-ray diffraction analysis has revealed that compound 1 crystallizes in the triclinic system Pi space group,which is a 1D "looped" chain with two types of alternating 14-membered rings.Solid-state CD spectra confirmed the single chirality of 1.Compound 2 is crystallized in the chiral trigonal P3121 space group and is a 3D architecture which can be can be envisioned as a 4-connected uninodal qtz(quartz)net.The photoluminescent and photocatalysis properties of compounds 1 and 2 have been investigated.The results show that compound 2 can be used as a potential luminescent material,and compounds 1 and 2 have created certain effects on the degradation of methylene blue(MB)and methyl orange(MO)under UV light.2.Synthesis,characterization and properties of transition metal coordination polymers based on auxiliary neutral bipyridine ligands and V-shape chiral alanine ligandReactions of V-shape chiral alanine ligand(H2L1)and transition metal ions by hydrothermal method or room temperature volatilization,in the presence of neutral rigid bipyridine ligands,afford three porous coordination polymers:[Co(Li)(bipy)(H2O)2]·3H2O(3),[Cu(L1)(bipy)(H2O)2]·3H2O(4)and[Cu(L1)(bpea)]·7H2O(5)(bipy=4,4'-bipyridine,bpea= 1,2-bis(4-pyridyl)ethane).Single-crystal X-ray diffraction analysis reveals that compound 3 and 4 are almost isostructural except the difference of metal ion.These crystal structures are solved in the tetragonal chiral space group P4322,showing a 3D 2-fold interpenetrating framework.PLATON analysis gave a total effective free volume of 19286.8 A3 per cell(29.5%of the crystal volume).Single-crystal X-ray diffraction has confirmed that compound 4 belongs to chiral tetragonal P41 space group,which is a 3D framework possessing large 1D open channels.PLATON calculations suggest that the free pore volume is 1058.3 A3 per unit cell(31.7%of the crystal volume)for the framework.Evacuated compounds 3 and 5 were used in studies of gas adsorption behavior.The result shows that the CO2 adsorption capacity of 5 is better than 3.The photo catalytic properties of complexes 3-5 show different degradative effects for MB and MO dyes.3.Synthesis,characterization and properties of transition metal coordination polymers based on linear chiral alanine ligandThree homochiral coordination polymers have been solvothermally synthesized in the absence/presence of neutral bipyridine ligands with linear chiral alanine ligand(H2L2)and transition metal ions:[Cd(L2)](6),[Co(L2)(bpea)(H2O)2]·2H2O(7)and[Ni(L2)(bpea)(H2O)2]·2H2O(8)(H2L2 = 4,4'-biphenylamide-2-(L-alanine)).Single-crystal X-ray diffraction analysis reveals that compound 6 crystallizes in the monoclinic system chiral space group C2,showing 2D layers which are stacked together in an ABAB overlapping fashion.Single-crystal X-ray diffraction analysis reveals that compound 7 and 8 are almost isostructural and crystallize in the orthorhombic chiral space group P212121,presenting a 1D right-handed helical chain.