The Design,Synthesis,Structure And Fluorescent Properties Of Coordination Complexes With Conjugated Schiff Base Including Donor-Acceptor Groups

D-A conjugated Schiff base inherits the optical,catalytic and magnetic properties of D-A compound,and is also characterized by easy synthesis process,high adaptability and reversible conversion of Schiff base compound.Based on the molecular design and functionality,a series of functionalized D-A conjugated schiff base ligands including their precursors were designed and synthesized.A number of symmetric and asymmetric complexes were obtained by routine method.The crystal structures of 36 novel compounds were investigated.Their fluorescence properties were studied.The main results are as follows:1.H₂L¹,H₂L²,H₂L³ and H₂L⁴ with different substituents were prepared by the condensation of salicylaldehyde with amino acids.Complexes of Zn（Ⅱ）,Ni（Ⅱ）and Co（Ⅱ）were synthesized and characterized by X-ray diffractometry and X-ray diffraction analysis The achieved six crystals（1-6）are showed as follows:[Cu（L¹）_n（1）[[Co（L¹）₂·Co（H₂O）₆]（2）（H₂L¹ =[（2-Hydroxy-benzylidene）-amino]-acetic acid）[Cu（L²）]_n（3）[Ni（L²）（H₂O）₃]（4）（H₂L² =[（5-Chloro-2-hydroxy-benzylidene）-amino]-acetic acid）[Cu（L³）（MeOH）]₂·（MeOH）（5）（H₂L³ =[（2,4-Dihydroxy-benzylidene）-amino]-acetic acid）[Cu（L⁴）（H₂O）]₂·（H₂O）₂（6）（H₂L⁴ =[（2-Hydroxy-5-nitro-benzylidene）-amino]-acetic acid）Complex 1 is a MOF-74 type coordination polymer structure in which the metal Cu（Ⅱ）is pentacoordinate binding to ONO atoms of ligand H₂L¹,and forms a dinuclear building block by sharing phenolic hydroxyl O with adjacent molecules.And then the blocks assemble into coordination polymer directly through coordinating with the uncoordinated carboxyl group 0 of the adjacent blocks on the axial position of Cu（Ⅱ）.2 are mainly composed of two parts,one is Co（Ⅱ）complex with two ligand and the other is Co（Ⅱ）·6H₂O.The functionalization of the complex 1 was studied by the ligand modification strategy.Ligand H₂L² was synthesized by the insertion of Cl in the ligand.Complex 3 is achieved with isomorphic pattern to 1.Its structure was the same as that of MOF-74,but with Clgroups in the channel.The complex of H₂L² and Ni（Ⅱ）are mononuclear.Ni（Ⅱ）is six-coordinated with ligand and three water molecules to form octahedral geometry.The ligands H₂L³ and H₂L⁴ were prepared by insertion of-OH and-NO₂ groups into the ligand.Their complexes 5 and 6 with Cu（Ⅱ）were all binuclear structures,which is similar to complexes 1 and 3.However,due to the strong hydrogen bonding ability of-OH and the steric-hindrance of-NO₂,the binuclear structures can t coordinate with the O atoms of neighboring blocks in the axial direction to form the MOF structure.2.Salen-type ligands H₂L⁵,H₂L⁶,H₂L⁷ and H₂L⁸ were prepared by condensation of diaminomaleonitrile（DAMN）with salicylaldehyde analogs.The ligands and its complexes were studied,and eight single crystals were obtained（7-14）.[（H₂L⁵）·（EtOH）₂]（7）[（H₂L⁵）·（DMF）₂]（8）[Zn（L⁵）（DMF）]·（DMF）₂（9）[Zn（L⁵）（Pyrazine）]·（MeOH）（10）（H₂L⁵ =2,3-Bis-[（2,4-dihydroxy-benzylidene）-amino]-but-2-enedinitrile）[Zn（L⁶）（EtOH）]·（EtOH）₂（11）（H₂L⁶ = 2,3-Bis-[（2,3-dihydroxy-benzylidene）-amino]-but-2-enedinitrile）[Al（L⁷）（H₂O2）₂]·（NO₃）（12）（H₂L⁷ =2,3-Bis-[（4-diethylamino-2-hydroxy-benzylidene）-amino]-but-2-enedinitrile）[Co（L⁸）（N₂）（DMF）]·（MeOH）₂（13）[Ni（L⁸）]₂·{[Ni（L⁸）]₂（CN）}·（H₂O）₂（14）（H₂L⁸ = 2,3-Bis-[（2-hydroxy-3-methoxy-benzylidene）-amino]-but-2-enedinitrile）(H₂L^8’= 2-Amino-3-[（2-hydroxy-3-methoxy-benzylidene）-amino]-but-2-enedinitrile)7 and 8 were obtained by recrystallization of H₂L⁵ in different solvents.In 7,molecules of H₂L⁵ have very good co-planarity due to the hydrogen bonds with solvent molecule ethanol,and the co-planarity was further transferred to the whole two-dimensional structure based on other hydrogen bonds.The restriction of molecular rotation and vibration in the system thtoguh hydrogen bonds reduced the energy dissipation,which euipped the system with good crystal-induced emission enhancement（CIEE）.In addition,H₂L⁵ molecule was recrystallized in other solvents and 8 was obtained.8 had two dimethylformamide（DMF）molecules besides H₂L⁵ molecule,but the DMF molecule can’t form hydrogen bonds to restrict the molecular rotation and vibration H₂L⁵,which resulted in the isomerization of H₂L⁵.Then,the fluorescence selectivity of H₂L⁵ to Al（Ⅲ）in the presence of methanol was studied.And the Al（Ⅲ）complex of H₂L⁵ was utilized to detect pyrophosphate through the fluorescence quenching response in methanol.According to the emission mechanism of Al-L complex,it was also applied to monitor the water content of methanol in industrial production.9 and 10 both were complexes of Zn（Ⅱ）and H₂L⁵,but the axial coordination molecules were not the same.The axial coordination molecule of 9 was DMF and 10’s was pyrazine.The supramolecular structures and fluorescence properties were studied.11,12 and 13 were mononuclear salen complexes.Zn（Ⅱ）was pentacoordinate,and Al（Ⅲ）and Co（Ⅱ）were hexacoordinated.Wihle,14 had three molecules in the asymmetric unit,two of which were salen complexes of Ni（Ⅱ）,and one was a complex of half dissociated of ligand with Ni（Ⅱ）.3.Based on the semi-condensated D-A type Schiff base H₂L⁸ in complex 14,5 semi-condensated D-A type Schiff bases had been designed and synthesized,and the complex with H₂L^11’,and Zn（Ⅱ）had been studied.Moreover,asymmetric ligand and the complexes of Zn（Ⅱ）,Mg（Ⅱ）were synthesized based on the semi-condensated Schiff bases.Nine crystals（15-23）were obtained.[(H₂L^5’)·（MeCN）]（15）(H₂L^5’=2-Amino-3-[（2,4-dihydroxy-benzylidene）-amino]-but-2-enedinitrile)(H₂L^9’)（16）(H₂L^9’=2-Amino-3-[（2-hydroxy-benzylidene）-amino]-but-2-enedinitrile)(H₂L^10’)（17）(H₂L^10’=2-Amino-3-[（2-hydroxy-4-methoxy-benzylidene）-amino]-but-2-enedinitrile)[Zn2(L^11’)₂（MeCN）（MeOH）]·（MeCN）（18）(H₂L^11’= 2-Amino-3-[（2-hydroxy-naphthalen-l-ylmethylene）-amino]-but-2-enedinitrile)[Zn(L^11a)（MeOH）]（19）（H₂Llla = 2-[（3,5-Di-tert-butyl-2-hydroxy-benzylidene）-amino]-3-[（2-hydroxy-naphthalen-1-ylmethylene）-amino]-but-2-enedinitrile）[Zn(L^11b)（H₂0）]（20）(H₂L^11b=2-[（4-Chloro-2-hydroxy-benzylidene）-amino]-3-[（2-hydroxy-naphthalen-l-ylmeth ylene）-amino]-but-2-enedinitrile)[Mg(L^11c))（EtOH）（H₂0）]·（0.5 EtOH）（21）(H₂L^11c=2-[（2-Hydroxy-naphthalen-1-ylmethylene）-amino]-3-[（2-hydroxy-5-nitro-benzylid ene）-amino]-but-2-enedinitrile)(H₂L^12a)（22）[Zn(L^12a)（MeOH）]（23）(H₂L^12a=2-[（3,5-Di-tert-butyl-2-hydroxy-benzylidene）-amino]-3-[（4-diethylamino-2-hydro xy-benzylidene）-amino]-but-2-enedinitrile)15,16 and 17 were crystals of H₂L^5’,H₂L^9’and H₂L^10’.The crystal structures of them proved the feasibility of the designed method.18 was a dinuclear complex of Zn（Ⅱ）and H₂L^11’.19 and 20 were asymmetric salen type complexes of Zn（II）.They were synthesized from H₂L^11’ and 3,5-di-t-butylsalicylaldehyde or 4-chlorosalicylaldehyde through the metal template method.20 was a Mg（Ⅱ）complex synthesized from H₂L^11’ and5-nitrosalicylaldehyde.Based on H₂L^12’,22 and 23 were synthesized as asymmetric salen-type ligand and complexes of Zn（Ⅱ）with 3,5-di-t-butylsalicylaldehyde on the other side.The fluorescence properties of the complexes had also been studied.4.By the condensation of 4-nitrobenzene-1,2-diamine with salicylaldchyde,a semi-condensated D-A type Schiff base was obtained,which failed to obtain bilateral salphen-type ligand.However,through one pot method with salicylaldehyde,4-nitrobenzene-1,2-diamine and template transition metals,salphen type complexes derived from same kind of salicylaldehyde analog were prepared.At the same time,semi-condensated D-A type Schiff bases were researched and crystals of H₂L^13’ and complex from H₂L^16’ were analysized.Based on H₂L^14’ and H₂L^16’,complexes with different kinds of salicylaldehyde analogs were synthesized.Thirteen crystals（24-36）were obtained.[Ni(L¹³)].（MeOH）（24）[Cu(L¹³)]·（DMF）（25）(H₂L¹³ =6,6’-（lE,1’E）-（4-nitro-1,2-phenylene）bwas（azanylylidene）bwas（methanylylidene）b was（3-（diethylamjno）phenol）[Ni(L¹⁴)]·（H₂O）₂（26）[Cu(L¹⁴)].（MeOH）₂（27）(H₂L¹⁴=4,4’-（lE,1’E）-（4-nitro,1,2-phenylene）bwas（azanylylidene）bwas（methanylylidene）di benzene-1,3-diol)[Ni(L¹⁵)]₂·（EtOH）（28）[Ni(L¹⁵)]·（MeOH）·（Dioxane）₂（29）[Cu(L¹⁵)]（30）[Zn(L¹⁵)（EtOH）]·（EtOH）（31）(H₂L¹⁵=6,6’-（1E,1’E）-（4-nitro-1,2-phenylene）bwas（azanylylidene）bwas（methanylylidene）b was（2,4-di-tert-butylphenol）)(H₂L^13’)（32）(H₂L¹³=2-[（2-Amino-5-nitro-phenylimino）-methyl]-5-（1-ethyl-propyl）-phenol)[Co(L^16’)₂]·（H₂O）₃（33）(H₂L^16’=1-[（2-Amino-5-nitro-phenylimino）-methyl]-naphthalen-2-ol)[Cu(L^4a]·（DMF）（34）[Zn(L^14a)（H₂O）]₂[Zn(L^14a)（MeOH）]·2（H₂O）4（35）(H₂L^14a=4-（{2-[（3,5-Di-tert-butyl-2-hydroxy-benzylidene）-amino]-5-nitro-phenylimino}-m ethyl）-benzene-1,3-diol)[Zn(L^16a)（DMF）]·（DMF）（36）(H₂L^16a-1-（{2-[3,5-Di-tert-butyl-2-hydroxy-benzylidene）-amino]-5-nitro-phenylimino}-m ethyl)-naphthalen-2-ol)24 and 25 were symmetric complexes of Ni（Ⅱ）and Cu（Ⅱ）with ligand H₂L¹³.26 and 27 were symmetric complexes of Ni（Ⅱ）and Cu（Ⅱ）with ligand H₂L¹³.28,29,30 and 31 were symmetric complexes of Ni（Ⅱ）,Cu（Ⅱ）and Zn（Ⅱ）.32 was the crystal of H₂L^13’.33 was a Co（Ⅱ）complex of H₂L^16’.34 and 35 were synthesized as asymmetric salphen type complexes of Cu（Ⅱ）and Zn（Ⅱ）with 3,5-di-tert-butyl salicylaldehyde on the other side based on H₂L^15’..36 was a asymmtric salphen type complex of Zn（Ⅱ）,which was obtained from H₂L¹6,and 3,5-di-tert-butyl salicylaldehyde in metal template method.The fluorescence properties of the Zn（Ⅱ）salphen type complexes were also studied.In summary,we firstly studied the modification of the MOF-74 analog’s channels by ligand-modifying method based on D-A conjugated Schiff base system from salicylaldehyde and glycine.Then,the ligand-related CIEE properties and the fluorescence properties of the complexes were studied by the symmetric D-A conjugated Schiff base ligands derived from salicylaldehyde and DAMN.The asymmetric Schiff base complexes derived from DAMN were studied based on semi-condensated D-A type Schiff base.At last,based on 4-NO₂ ortho-phenylenediamine,two types of asymmetric D-A conjugates were synthesized.One was asymmetric D-A type complexes with same kind of salicylaldehyde analog through one pot process.And the other was asymmetric D-A type complexes with different kinds of salicylaldehyde analogs based on semi-condensated D-A ligands throgh metal template method.A total of 36 crystal structures were studied.