Studies On The Synthesis, Structures And Properties Of Metal Coordination Compounds (Polymers) Based On Dicarboxylic Acid-acylated N-acyl-salicylhydrazide Ligands

The syntheses and properties of discrete polynuclear complexes and coordination polymers ranging from 1D to 3D have attracted great research interest for many years because of their intriguing architectures and potential applications in catalysis, electronics, nonlinear optics, magnetic materials, porous materials, as well as their relevance to bioinorganic chemistry. As a type of multidentate ligands containing N, O coordination atoms, rich hydrogen-bonded donors and accepters, as well as the great conjugated system, the N-acyl-salicylhydrazide ligands have been widely used to construct polynuclear metal complexes and coordination polymers with interesting structural motifs. Based on the hot research point on the construction of functional coordination compounds with N-acyl-salicylhydrazide ligands, in this thesis, we made an extension of these ligands from the prevalent monoacyl-monosalicylhydrazide to the multiacyl-multisalicylhydrazide ligands, and made use of them in the construction of metal coordination compounds (polymers). With the starting materials of N,O-containing multidentate ligands of N,N’-(2,6-pyridinedicarboxyl)-disalicylhydrazide (H6L) and (1 R,3 S)-1,2,2-trimethyl-3-{2-[5-(2-hydroxyphenyl)-1,3,4-oxadiazole]}-cyclopentanecarboxylic acid (H2L’) derived from the acylation of 2,6-pyridinedicarboxylic acid or chiral camphoric acid and salicylhydrazide, twenty-three new coordination compounds (polymers) were obtained with discrete mono-, multi-nuclear, cyclic decanuclear and dodecanuclear, as well as 1D and 2D polymeric structures. The properties of these compounds were investigated as well.The contents include four parts as follows:1. Eight metal coordination compounds (polymers) with diverse structures were synthesized from the hendecadentate ligand of N,N’-(2,6-pyridinedicarboxyl)-disalicylhydrazide (H6L) which derives from the acylation of 2,6-pyridinedicarboxylic acid and salicylhydrazide. The magnetic and luminescent properties of these compounds were investigatedEight coordination compounds (polymers) were obtained from the reaction of H6L ligand with transition metal or Pb(II) salts:[M(H4L)(H2O)2]-2DMF [M= Mn (1), Co (2), Zn (3)], [Cd(H4L)(Py)2]·DMF·Py (4), [Co3(H4L)4(H2O)4]-2DMF-2H2O (5), [Ni4(H2L)2(Py)4]·2DMF·H2O (6), [Cu6(L)2(py)4]n (7) and [Pb2(H5L)2(NO3)2]·2DMF (8) (py= pyridine). With the H6L ligand coordinating to metal ions in six different modes, the mononuclear complexes 1-4, centrosymmetric mixed-valence trinuclear complex 5, tetra-and bi-nuclear complexes 6 and 8, as well as the 1D polymer 7 featuring hexanuclear secondary building units were formed, respectively. The hexanuclear unit in 7 is the highest-nuclear unit of N-acyl-salicylhydrazide-containing coordination polymer formed by the connection of polynuclear units via N-acyl-salicylhydrazide ligand itself. The luminescent studies of 3 and 4 indicate that the emissions of them are both assigned to intraligand Ï€â†'Ï€* transition, and for complex 8, no fluorescent emission can be observed. The magnetic study of compound 7 indicates an antiferromagnetic coupling interaction between Cu(II) ions.2. Two metallamacrocycle compounds were synthesized from H6L ligand. The magnetic and luminescent properties of these compounds were investigatedConventional reaction of H6L ligand with organic-anionic Mn(II) salt afforded a mixed-valence dodecanuclear compound with wheel-like macrocyclic structure: [Mn"6Mnâ…£6(L)6(H2O)12] (9). The addition of bridging ligand imidazole in the reaction system of H6L and Zn(NO3)2-6H2O yielded complex [Zn10(H4L)2(H2L)4(H20)4]0o.5{[Zn10(H4L)2(H2L)4(im)(Him)(H20)]-}n (10) (Him=imidazole), which is composed of discrete decanuclear Zn(II) metallamacrocycle and ID chain formed from the linkage of decanuclear zinc(II) units by imidazole molecules. These compounds are the first examples of an N-acyl-salicylhydrazide-based metallamacrocycle in which the N-acyl-salicylhydrazide ligand didn’t coordinate to a trivalent octahedral metal ion. The H6L Lligands in them present three kinds of coordination modes different from those in complexes 1-8. The similarities and differences of monoacyl-monosalicylhydrazide and multiacyl-multisalicylhydrazide ligands in the construction of metallamacrocycles were analysed. The magnetic study of 9 indicates a ferromagnetic coupling interaction between manganese ions. The luminescent property of 10 shows that the emission of this compound is due to the transition from ligand to metal ions (LMCT).3. A series of discrete polynuclear complexes were synthesized from the reaction of H6L ligand with lanthanide chlorides or nitrates. The magnetic and luminescent properties of these compounds were investigatedThe reaction of H6L ligand with lanthanide chlorides or nitrates afforded eight coordination compounds, which were, [M2(H3L)2(H2O)6]·2DMF-4H2O [M= La (11), Pr (13)], [Sm2(H3L)2(H2O)4]·2DMF-5H2O (14), [M2(H3L)2(H2O)4]-3DMF·H2O [M= Gd(15), Tb (16), Dy (17)] and [Er2(H3L)2(H2O)4]·2CH3OH·2DMF (18) with similar binuclear structures, and tetranuclear complex [Ce4(H4L)6(DMF)2(H2O)2]·2CH3OH-4DMF-4H2O (12). There shows no change in the structure of these complexes from light, middle to heavy rare earth. However, there presents bi-and tetra-nuclear structures in the light rare earth complexes. The H6L ligands in these rare earth complexes show two kinds of coordination modes different from those in the preceding complexes 1-10. The magnetic properties of 13,15 and 17 were investigated, antiferromagnetic coupling interaction can be observed in them. The luminescent study of 14 indicates that the the emission spectrum of this complex is assigned to the characteristic spectrum of Sm(III) ion, which is slightly disturbed by H6L ligand.4. Five coordination polymers were synthesized from the hexadentate ligand of (1 R,3 S)-1,2,2-trimethyl-3-{2-[5-(2-hy droxyphenyl)-1,3,4-oxadiazole]}-cy clopentanecarboxylate (H2L’), which is the derivative of chiral camphoric acyl-salicylhydrazide. The CD spectra and luminescent properties of these compounds were investigatedBy the reaction of H2L’ligand with transition metal acetates, five coordination polymers were obtained:{[M(L’)(py)2]-DMF}n [M=Co(19), N1(20)], [Cu(L’)(py)]n(21), [M2(L’)2(py)2]n [M = Zn (22), Cd (23)]. Among of them, compounds 19 and 20, which were obtained by low temperature solvothermal reaction, exhibit the similar 1D right handed helical chain structures. By the conventional solution method, compounds 21-23 were synthesized. Compound 21 shows 1D chain structure and compounds 22 and 23 present similar 2D structures. Different from the only right handed helical chain in 19 and 20, there present left and right handed helical chains arranged alternately in 21-23. The CD spectra of 19-23 indicate the chiral characteristic of them. The luminescent studies of 22 and 23 indicate that the emissions of them are both assigned to intraligand Ï€â†'Ï€* transition.