Studies On The Synthesis,Structure And Properties Of Metal Complexs Using Hydroxyethylhydrazine And Its Schiff Base As Ligands Or Precursors

In recent years,Lanthanide complexes and transition metal complexes have attracted much attention owing to their unique properties and potential applications in fields such as magnetism,electriClty and optics.Chemists have focused on synthesis,structure and properties of these complexes and made a series of breakthroughs.In this paper,we designed three ligands.Their reaction with rare earth metal ions ortransition metalions gave a series of 3d and 4f complexes,the structures and magnetic properties of which were studied in detail.The main research works of this thesis are listed below.1.[Ni₃(HL¹)₆]Cl₆·6CH₃OH-6H₂O(1),[Ni3(HL1)4(CH₃OH)2Cl4]Cl2(2),[Co2(HL1)4Cl2]Cl2(3),{[Co(L1)(H₂O)]ClO4}n(4),{[Co3(HL1)2(L1)2Cl3]Cl}n(5),[Co4(L2)4](N03)4·2CH₃CN-H₂O(6)and[Co(HL2)2](NO₃)2(7)were separated from the reactions of hydroxyethyl hydrazine(HL1)with NiCl₂·6H₂O,Co(ClO4)2·6H₂O,CoCl2·6H₂O or Co(NO₃)2·6H₂O.The Ni(?)ions in(1)and(2)are bridged to form linear trinuclear skeletons.The two Co(?)ions in complex(3)are consolidated by four hydroxyethyl hydrazine ligands,forming a dinuclear skeleton.Complex(4)features mononuclear Co secondary building units,which are bridged by hydroxyethyl hydrazine ligands to form a one-dimensional structure.Complex(5)features V-shaped trinuclear Co3 secondary building units,which are bridged by hydroxyethyl hydrazine ligands to form a one-dimensional structure.Variable-temperature solid state magnetic susceptibilities measurements of(1)-(5)in the temperature range of 2-300 K revealed the presence of dominant antiferromagnetic exchange interactions between the metal centres in(1)-(5).2.The reactions of Ln(NO₃)₃ with the Shiff-base ligand of 2-((2-pyridinylmethylene)hydrazine)ethanol(HL3)and CH₃COOH in the presence of triethylamine afforded a series of lanthanide complexes[Ln2(L2)2(NO₃)2(OAc)4]·2CH₃CN(Ln=Gd(8),Tb(9),Dy(10),Ho(11),Er(12)).[Cu2(HL3)2(S04)2(CH₃0H)2](13)and[Cu3(L3)2(CH₃COO)2]n·2nCH₃0H(14)were separated from the reactions of 2-((2-pyridinylmethylene)hydrazine)ethanol(HL3)with Cu(S04)2·5H20,Cu(OAc)2·H20,respectively.[M(HL3)2](ClO4)2(M=Co(15),Ni(16)),[Co(HL3)2S04](17),[Ni(HL3)2S04]·CH₃0H(18),[Cu(HL3)2Cl]Cl·(19)were also prepared,which show mononuclear structures.Compounds(8)-(13)show similar dinuclear cores with the two lanthanide ions bridged by four acetate ligands in the ?₂-?l:?2 and ?₂-?1:?1 bridging modes.The two Cu(?)ions in complex(13)are bridged by four O atoms from the two JV42-ligands,forming the dinuclear skeleton.Complex(14)presents trinuclear units[Cu3(L3)2(CH₃COO)2]as repeating units,which are bridged by CH₃COO-ions to form a one-dimensional ladder.Their magnetic properties were investigated.It revealed antiferromagnetic interactions between the metal ions in(8)and(14)complexes,however ferromagnetic interactions between the the metal ions in(9)and(13).The profiles of XmT versus T curves of(10)-(12)are probably from thermal depopulation of the Stark sublevels of Ln? ions and/or weak antiferromagnetic interactions.3.The solvothermal reactions of Ln(NO₃)₃ with 2-((2-pyridinylmethylene)hydrazine)ethanol(HL3)in the presence or absence of 2-Pyridinecarboxaldehydeafforded three coordination polymers[Ln3(L4):2(L5)2(N03)5(H20)]n·2THF.CH₃0H·H20(Ln=Dy(20),Tb(21),Gd(22))and one pentadecanuclearcluster[Dy15(OH)20(L5)10(NO₃)i5(H₂O)15](23).The ligands of 2-Pyridinecarboxylate(HL5)and N-(pyridyl-2-hydroxylmethyl)-N'-(pyridyl-2-methylene)-hydroxyethyl hydrazine(HL4)in these compounds were generated in-situ in the corresponding reactions.Their magnetic properties were investigated.It revealed antiferromagnetic interactions between the Gd? ions in complex(22),and ferromagnetic interactions between the Dy? ions in complex(20).The profiles of ?mT versus T curves of(21)are probably from the thermal depopulation of the Stark sublevels of Ln? ions and/or weak antiferromagnetic interactions.The alternating-current susceptibility measurements of(20)present frequency and temperature-dependent out-of-phase signals under a zero direct-current field,relvealing the presence of typical slow magnetic relaxation behavior in this compound.