Synthesis, Characterization And Properties Of Nitrogen-containing Aromatic Heterocyclic Ligands New Complex Research

Following the pioneering work of Werner, an enormous amount of relevantinformation has been collected concerning the physical and chemical properties oftransition metal complexes. In particular, the magnetic properties of these systems havebeen well documented in the last three decades. The main points deserving attention arethe understanding of the correlation factors between magnetic coupling properties andits relevant structures for those magnetic compounds, in which relevant spin-carrierswere bridged by sole atoms or multi-atoms'molecule or ions. On the other hand, papersdeal with the magnetic coupling through intermolecular forces such asÏ€-Ï€stacking andhydrogen bond, etc. are very limited.This dissertation aims to search for some factors that dominate magnetic couplingproperties and to correlate molecular force and its magnetic coupling properties. Basedon this aspiration or aim, twenty-four novel coordination complexes have beensynthesized with nine ligands, which involves 2-Substituent and2,9-Bisubstituent-1,10-phenanthroline derivatives, and the magnetism of a reported CuIIcomplex (5) has been studied. The detailed information is as follows. Five complexesdeal with 2-hydroxyl-1,10-phenanthroline (L1) as ligand: [Ni(L1)(OSO3)(H₂O)₃] 5H₂O(1), [Cu(L1)(C₂O₄)(H₂O)] H₂O (2), [Ni(L1)(O₂C₃O₂H₂)(H₂O)₂] [Ni(L1)(O₂C₃O₂H₂)(H₂O)₂] 5H₂O (3), [Co(L1)(OSO3)(H₂O)3] 5H₂O (4),[Cu₂(μ1,3-SCN)₂(L1)₂(OCH₃)₂(HOCH₃)₂] (5); two complexes deal with2-(1,2,3-1H-triazol-l-yl)-1,10-phenanthroline (L2) as ligand: [Mn(L2)(ONO)(H₂O)2] (L2)-(ClO₄) (6) and [Co(L2)(ONO)(H₂O)₂]·(L2)(ClO₄) (7); three complexes deal with2-(1,10-phenanthroline-2-ylamino) ethanol (L3) as ligand: [Cu₂(L3)₂(μ-OSO3)₂] (8),[Co2(μ2-Cl)₂(L3)4] SbF6(9) and [Ni(L3)2(N3)2] (10); one complex deals with2-(4-phenyl-1H-pyrazol-1-yl)-1,10-phenanthroline (L4) as ligand:[Cu(L4)(ONO₂)(CH₃OH)] (NO₃) (11); one complexes deals with2-(2-keto-pyridyl-1)-1,10-phenanthroline (L5) as ligand: [Ni(L5)2(H₂O)] (ClO4)2 2H₂O(12); six complexes deal with [2,9-di(3,5-dimethyl-1H-pyrazol-1-yl)]-1,10-phenanthroline(L6) as ligand: [Cu(L6)(NCS)(CH₃OH)] ClO4(13), [Cu(L6)(ClO4)2] (14), [Mn(L6)(NCS)₂] (15), [Ni(L6)(NCS)₂] (16), [Co(L6)(ONO₂)₂] (17) and [Mn(L6)(ONO)(CH₃OH)] ClO₄(18);four complexes with [2,9-di(1H-pyrazol-1-yl)]-1,10-phenanthroline (L7) as ligand:[Ni(L7)(NCS)₂] (19), [Cu(L7)₂] (ClO₄)₂(20), [Cu(L7)(Cl)₂] [Cu(L7)(Cl)₂] (CH₂Cl2) (21) and[Cu(L7)(NCS)₂] (22); two complexes deal with [2,9-di(methoxy)]-1,10-phenanthroline (L8)as ligand: [Cu(L8)(CH₃OH)(Cl)₂] (23) and [Cu₂(μ2-Cl)₂(L8)2Cl₂] (24); one complex dealswith 2,9-dihydroxy-1,10-phenanthroline (L9) as ligand: [Co(L9)(H₂O)₂(Cl)₂] (25). Thetwenty-four novel complexes were characterized by infrared spectra and X-raycrystallographic analysis. The complex (19) was studied by UV-vis. solid electronicreflectance spectrum. The variable-temperature magnetic susceptibilities for complexes(1), (5), (6) and (19) were measured at 2-300 K and the fittings on the obtained magneticdata were made and the some experimental magnetic coupling properties were obtained.In order to understand the correlation between the molecular forces and the relevantmagnetic coupling properties, the theoretical calculations on complexes (1), (2), (3), (5),(6), (8), (10), (11), (13), (14), (15), (16), (19), (20), (21), (23) and (24) were performed.The magnetic interactions between metal cations were studied on the basis of densityfunctional theory (DFT) coupling with the broken-symmetry approach (BS). Thecalculations gave the information involving the spin density, the magnetic coupling signand the magnetic coupling magnitude of the relevant magnetic coupling pathways. Fromthe information the correlations between the magnetic coupling properties and therelevant structural factors have been studied and some interesting results are obtained.On magnetic coupling sign ofÏ€-Ï€stackings McConnell I spin polarization mechanismhas been used to explain the magnetic interaction of the complexes. Based on the studyof complex (5), the magnetic coupling magnitude of theÏ€-Ï€stacking pathways seemsrelevant with its Wiberg bond indexes and this is the first suggestion that correlatesmagnetic coupling magnitude with their relevant Wiberg bond indexes.The major contribution of this dissertation is as follows:1. Based on the data of the experiment and the theoretical calculations, one of thedominated factors that correlateÏ€-Ï€stacking's magnetic coupling strength with itsÏ€-Ï€stacking strength has been put forward for the first time.2. Based on the data of the theoretical calculations, the conclusion is obtained that McConnell I spin polarization mechanism is not suitable to explain magneticcoupling signs that arise from molecular forces.The obtained information in this dissertation may benefit to understand the magneticcoupling mechanism arisen from molecular force and it may also benefit to design andsynthesize ideal molecule-based ferromagnet, especially for those ferromagnet basedon complexes and intermolecular force.