Syntheses, Structures And Properties Of The Complexes Based On Chiral Ligands Containing Nitrogen And Oxygen Atom

In recent years, the design and synthesis of chiral coordination polymers have attractedincreased attention and become a hotspot in the research of field because of intriguing andbeautiful structure and potential applications in biological medicine, enantioselectiveprocesses, molecular recognition, sorption, asymmetric catalysis, luminescence, andmagnetism and etc. On the basis of summarizing the research development of chiralcoordination polymers found that chiral compounds can be obtained by many routes.Comparing these routes, the use of chiral species is the most direct and effective method togenerate chiral compounds. Therefore, a series of coordination polymers constructed by chiralligands N-acetyl-L-tyrosine (Hacty) and s-(+)-mandelic acid have been synthesized, and theircrystal structures and properties were determined. In this paper, the main results are asfollows:First, seven homochiral coordination compounds constructed by N-acetyl-L-tyrosine:{[Zn(acty)(4,4’-bipy)2(H2O)2] NO32H2O}n(1)、{[Co(acty)(4,4’-bipy)2(H2O)2] NO32H2O}n(2)、{[Cd(acty)2(4,4’-bipy)H2O] H2O}n(3)、{[Cd(acty)(bpe)2(Ac)]6H2O}n(4)、[Cu2(acty)2(1,10-phen)2(OH)2](5)、[Cu6(2,2’-bipy)6(OH)8]3NO3(Hacty)(acty)8H2O (6)、[Cu(acty)2(4,4’-bipy)(H2O)]n(7)(Hacty=N-acetyl-L-tyrosine; bipy=bipyridine;1,10-phen=1,10-phenanthroline; bpe=1,2-bis(4-pyridyl)methane) have been synthesized andcharacterized by X-ray single-crystal diffraction analysis, elemental analysis, IR, thermalanalysis, fluorescent properties and magnetic properties were studied.Compounds1and2crystallize in the triclinic chiral space group P1and feature anisostructural1D infinite chain. The neighboring chains are connected by π π stacking to form2D network and further linked into a3D supramolecular structure via hydrogen bondinteractions. Compounds3,4,6and7crystallize in the monoclinic space group P21.Compound3and7shows a2D network,3contains left-handed helical chain and7containsright-handed helical chain. Compound4generates1D infinite chains and6consists of thepolynuclear [Cu6(2,2’-bipy)6(OH)8] unit which form a “stair steps-likes” structure, and theadjacent polynuclear clusters hold together by π π stacking between the outer bipy rings to form a set of2D layer. Compounds3,4and6are further extended to a3D supramoleculararchitecture through hydrogen bonds interactions. The dinuclear complex5crystallizes in theorthorhombic space group P21212, which are connected by intermolecular hydrogen bondsresulting in the formation of2D layers. Fluorescent properties of compounds1,3and4inDMSO solution at room temperature were studied. Results of luminescent studies ofcompounds1,3and4indicate that they are all potential blue fluorescent materials. Complex5shows antiferromagnetic interactions between the Cu(II) centers of each dicopper unit.Second, three homochiral coordination compounds constructed by s-(+)-mandelic acid,and unexpectedly, two compounds were obtained:[Ni(MA)2(2,2’-bipy)] H2O (8)[Ni(MA)2(bpe)]n(9)、[Co(MA)2(bpe)]n(10)、[Cu(2,2’-bipy)(H2O)2SO4]n(11)、[Co(4,4’-bipy)-(HCOO)2]n(HMA=s-(+)-mandelic acid; bipy=bipyridine; bpe=1,2-bis-(4-pyridyl)methane)have been synthesized and characterized by X-ray single-crystal diffraction analysis,elemental analysis, IR, thermal analysis, and magnetic properties of8and9were also studied.Compound8crystallize in the hexagonal chiral space group P6122and further connectedinto2D supramolecular layer by hydrogen bond and π π stacking interactions. Compounds9and10crystallize in the monoclinic space group C2/c, forming the isostructural1D infinitechain, which further linked into3D supramolecular structure via hydrogen bond. Thes-(+)-mandelic acid are chiral ligands, but the two compounds synthesized are achiral. Thismay be caused by the solvothermal conditions. During the synthetic procedure, half of theligands undergo inversion and were present as the enantiomer, so mandlic acid racemized andthe compounds are achiral. Unexpectedly, compounds11and12were obtained. Compound11crystallize in the monoclinic space group C2/c and present1D chain linking by SO42-,which further connected by hydrogen bond and π π packing interactions to form2Dsupramolecular network. Compound12crystallize in the tetragonal space group P43212anddisplay chiral3D structure. Magnetic properties study indicates that compounds8and9showweak antiferromagnetic interactions.