Homochiral Coordination Polymers Based On Different Chiral Amino Acid Derivatives Ligands

In recent years,homochiral coordination polymers?CPs?have been favored by researchers because of their potential applications in chiral separation,correspondence selection,asymmetric catalysis,etc.,which has become one of the new research hotspots in the field of coordination chemistry.The combination of natural amino acids of inexpensive as well as readily available and carboxylic acid organic ligands with strong coordination ability and flexible coordination modes,is the most direct and effective strategy for the preparation of homochiral coordination polymers.In this paper,we have integrated L-alanine and L-proline into 4,4'-oxybis?benzoyl chloride?and 4,4'-biphenyldicarbonyl chloride by amide condensation reaction,and then obtained three chiral ligands with different flexibility.Nine kinds of novel homochiral coordination polymers with different dimensions have been synthesized by self-assembly reactions of different chiral ligands using linear or V-type pyridine auxiliary ligands and metal ions under suitable conditions.This paper mainly includes three section works:1.One-dimensional and three-dimensional homochiral coordination polymers based on phenylether chiral alanine derivative ligandsFour homochiral coordination polymers have been synthesized using phenylether chiral alanine derivative ligands and in the presence/absence of bpea auxiliary ligands:[Cu₂?DPOALa?₂?bpea?₂ H₂O]·7H₂O?1?,[M?DPOALa?H₂O]·H₂O?M=Mn,2;Co,3;Cd,4??H₂DPOALa=4,4'-Oxybisamide-2-?L-alanine?,bpea=1,2-bis?4-pyridyl?ethane?.All the compounds have been analysized by Single-Crystal X-ray diffraction analyzer.Compound 1 crystallizes in the chiral monoclinc space group P2₁,which is a one-dimension chain in which the metal ions are surrounded by the chiral ligands.Compounds 2-4 are isomorphic and crystallize in the chiral orthorhombic space group P2₁2₁2₁,which shows a fantastic 3D framework constructed from twisted left-handed helical chains.Magnetic studies of compounds 2 and 3 indicate that there is a typical antiferromagnetic interaction between the Mn?II?metal ions in compound 2,and there is a ferromagnetic interaction between the Co?II?metal ions in compound 3.Moreover,the solid-state photoluminescent spectra of compound 4 have been investigated,which shows a strong emission at 413 nm.2.Two-dimensional homochiral coordination polymers based on phenylether chiral proline derivative ligands.Inthiswork,twonovelhomochiralcoordinationpolymers[Cd_2.5?DPOPRo??HDPOPRo?₃?bpee?_2.5]·13H₂O?5?and[Cu₂?DPOPRo?₂?bpee?₂]·14H₂O?6?are successfully obtained under hydro?solvo?thermally conditions.?H₂DPOPRo=4,4'-Oxybisamide-2-?L-proline?,bpee=1,2-bis?4-pyridyl?ethene?.Two attractive 2D architectures have been confirmed by Single-Crystal X-ray crystallographic analysis.Compound 5 crystallizes in the chiral monoclinc space group C2.In 5,the interesting"crab-like"structural units are connected by the binuclear Cd?II?ions and bpee to form a novel layered structure.Compound 6 crystallizes in the chiral monoclinc space group P2₁.In 6,the interesting left-handed helical chains are jointed together by the bpee auxiliary ligands to construct the finally 2D layered network.The solid-state photoluminescent spectra of compound 5 have been studies,which shows a strong emission at 414 nm.3.Three-dimensional homochiral coordination polymers based on biphenyl chiral proline derivative ligands.On the basis of the hydro?solvo?thermally reactions,three homochiral coordination polymers,[M?BPPRo??V-4?H₂O]·3H₂O?M=Cd,7;Zn,8?,[Cu?BPPRo??bpea?H₂O]·7H₂O?9?,have been successfully synthesized with biphenyl chiral proline derivative ligands and V-4/bpea auxiliary ligands.?H₂BPPRo=4,4'-biphenylamide-2-?L-proline?,V-4=1,3-phenylamide-bis-?4-pyridine??.Single-Crys tal X-ray diffraction exhibits that compounds 7 and 8 are isomorphic except for minor differences in the coordination environment,which crystallize in the chiral orthorhombic space group P2₁2₁2₁,showing a 3D architecture containing two different kinds of left-hand helical chains constructed from chiral ligands and V-4 auxiliary ligands,respectively.Compound 9 crystallizes in the chiral monoclinc space group C2.Through the self-assembly reaction utilizing metal Cu?II?ion,chiral ligands and bpea have successfully constructed right-handed helical chains and linear chains respectively,and then cooperated with each other masterly to form a 3D architecture.PLATON caculations shows that the porosity of compound 9 is 25.89%of the crystal volume.All compounds include two identical structural features:?1?all helical chains from chiral ligands are arranged in an ABAB overlapping fashion;?2?all compounds show a 3D diamond net with a 4-connected uninodal?6⁶?topology.The solid-state photoluminescent spectra of compounds 7 and 8 have been studies,which show a strong emission at 424 nm and 437 nm,respectively.