Homochiral Coordination Polymers Based On Chiral Dicarboxylic Acids And Bipyridyl Auxiliary Ligands

In recent years, chiral coordination polymers (CPs) have received remarkable attention not only because of their intriguing variety of structures, but also because of their potential applications such as asymmetric catalysis, non-linear optical properties, magnetism, and so on. In this article, choosing enantiopure (1R,2R)-1,2-cyclohexane-dicarboxylic acid (H2L) and (2R,2R’)-2,2’-(([1,1’-biphenyl]-4,4’-dicarbonyl)bis(azan-edily))dipropionic acid (H2L’) as the chief ligands to react with transition metals. Eight new homochiral coordination polymers mixed with varied auxiliary bipyridyl ligands have been constructed under hydro(solvo)thermal conditions. The photoluminescent, magnetic, and photocatalysis properties of some compounds have been investigated on the basis of crystal structural analysis.The dissertation can be summarized as following:1. Chiral coordination polymers based on (1R,2R)-1,2-cyclohexanedicarboxylic acid and the photoluminescent property research. Two coordination polymers have been synthesized in the absence/presence of neutral rigid bipyridyl ligands: [Zn3(L)2(OH)2](1), [Cd(L)(bpe)2(H2O)2]·H2O(2).H2L=(1R,2R)-1,2-cyclohexanedicar-boxylic acid, bpe=1,2-bis(4-pyridyl)ethylene. Complex 1 crystallizes in the orthorhom-bic chiral space group P212121. The Zn(II) ions are bridged by the μ3-OH oxygen atoms to form a [Zn3(μ3-OH)2]n4+ 2D layered structure with 63-hcb topolyge running along the ab plane.There exist right-handed helicl chains within the layer, which is consistent with the positive cotton effect of the CD spectra. The complex 2 is crystallized in the monoclinic chiral space group C2. The L2- ligands connect Cd(II) ions to form a 1D (CdL)n chain along the c-axis. The solid-state photoluminescent property manifests that 2 has potential application acting as fluorescent material.2. Chiral coordination polymers based on (1R,2R)-1,2-cyclohexanedicarboxylic acid and the magnetism property research:(1) Five coordination polymers have been synthesized in the presence of different neutral rigid bipyridyl ligands:[Co(L)(bpa)2(H2O)3]·4H2O(3),[Ni(L)(bpa)(H2O)3]·2H2O(4),[Ni(L)(bpe)2(H2O)2]·H2O(5),[Co(L)(bpe)2(H2O)2]·H2O(6),[Cu3(HL)2(L)2(bpy)3]·4H2O(7),where bpa= 1,2-bis(4-pyridyl)ethane, bpy= 4,4’-bipyridine. The complex 3 is crystallized in the monoclinic chiral space group P2(1). The bpa ligands connect Co(II) ions to form a 1D chain and the carboxylic ligands are decorated on the same side in parallel manner. The compound 4 is crystallized in the orthorhombic chiral space groupP212121. The gauche bpa ligands link Ni(Ⅱ) ions to form a 1D left-handed helical chain, which is consistent with the negative cotton effect of the CD spectra. Complexes 5 and 6 have the isomorphous structure with complex 2. The complex 7 is crystallized in the monoclinic chiral space group C2. The [Cu2(CO2)2] binuclear units of Cul(II) ions and Cu2(Ⅱ) are connected by the L2- ligands to form a 1D infinite chain. The bpy ligands link neighboring chains into a (4,4)-connected 2D network running along the ab plane.(2) 5 show antiferromagnetic interactions between the 1D chains.(3) Structural varieties of complexes show that different N-donor ancillary ligands play crucial roles in regulating structures of the coordination polymers.3. Chiral coordination polymer based on (2R,2R’)-2,2’-(([1,1’-biphenyl]-4,4’-dicar-bonyl)bis(azanedily))dipropionic acid and the photocatalysis character research:(1) The synthesis and characterization of the chiral ligand (2R,2R’)-2,2’-(([1,1’-biphenyl]-4,4’-dicarbonyl)bis(azanedily))dipropionic acid (H2L’). The new chiral ligand H2L’ was obtained by the reaction of 4,4’-biph -enyldicarbonyl chloride and L-Alanine Methyl Ester Hydrochloride. The IR and NMR spectras validate the correctness and purity of the ligand.(2) A chiral coordination polymer has been synthesized under hydrothermal condition in the presence of bpa bipyridyl ligand:[Cu(L’)3(bpa)(H2O)]·2H2O(8) [H2L’=(2R,2R’)-2,2’-(([1,1’-biphenyl]-4,4’-dicarbonyl)bis(azanedily))dipropionic acid]. Complex 8 is crystallized in the orthorhombic chiral space groupC222(1).The chiral ligands connect Cu(Ⅱ) ions to form a 1D left-handed helical chain and bpa ligands link Cu(II) ions to form a 1D zigzag chain. Solid-state CD spectra confirmed the single chirality. (3) Tthe photodegradation of methyl orange experiment under the UV-light indicate that 8 can be a heterogeneous photocatalyst.