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Title: Synthesis, reactivity and magnetic properties of some ruthenium and osmium complexes bearing Schiff base ligands
Other Titles: Han liao he e Xifu jian jin shu luo he wu de he cheng, fan ying ji ci xing yan jiu
含釕和鋨席夫鹼金屬絡合物的合成, 反應及磁性研究
Authors: Xiang, Jing ( 向景)
Department: Department of Biology and Chemistry
Degree: Doctor of Philosophy
Issue Date: 2010
Publisher: City University of Hong Kong
Subjects: Osmium compounds.
Ruthenium compounds.
Complex compounds -- Synthesis.
Ligands (Biochemistry)
Schiff bases.
Notes: CityU Call Number: QD181.O7 X53 2010
xi, 232 leaves : ill. 30 cm.
Thesis (Ph.D.)--City University of Hong Kong, 2010.
Includes bibliographical references (leaves 204-218)
Type: thesis
Abstract: The thesis includes four parts: (1) reactivity of RuVI(N), OsVI(N) complexes containing a tridentate O^N^O Schiff base ligand; (2) synthesis and reactivity of OsIII(NHCN) and OsIII-guanidine complexes containing a bidentate O^N ligand; (3) synthesis and magnetic properties of a series of polynuclear complexes based on paramagnetic ruthenium building blocks; (4) ruthenium-activated amine-amine coupling reaction. In part 1, the reactivity of two neutral nitrido complexes containing a tridentate Schiff base ligand [OsVI(N)(L1)Cl(OH2)] (1.1) and [RuVI(N)(L1)Cl] (1.2) (L1 = the anion of N-salicylidene-2-aminophenol) towards various nucleophiles such as CN-, OH-, CN- and N3- have been studied. Compound 1.1 reacts with various equivalents of CN- to generate a series of cyano complexes. Addition of one equivalent of CN- to a solution of 1.1 gives (PPh4)[OsVI(N)(L1)(CN)Cl]. Addition of 3 equivalents of CN- leads to the formation of (PPh4)2[OsVI(N)(L2)(CN)2] (L2 = the anion of (2-hydroxyphenyl)(2-hydroxyphenylamino)acetonitrile), where nucleophilic addition of CN- to the imine function on L1 ligand has occurred. Addition of excess CN- leads to nucleophilic attack on the nitride, followed by reductive protonation to generate a hydrogen cyanamido species, [OsIII{N(H)CN}(L3)(CN)3]2-, in which transformation of the tridentate Schiff base to a deprotonated bidentate 2-(2-hydroxyphenyl)benzoxazole (L3) has occurred. Reaction of (PPh4)2[OsVI(N)(L2)(CN)2] with PPh3 leads to a neutral complex [OsIII(NHPPh3)(PPh3)(L3)(CN)2], where a similar ligand transformation occurs. Reactions of 1.2 with 3 and 10 equivalents of CN- in methanol give two paramagnetic tricyano compounds (PPh4)2[RuIII(L1)(CN)3] and (PPh4)2[RuIII(CN-L1)(CN)3], respectively. Treatment of 1.2 with excessive NaN3 in methanol affords a triazido compound, (PPh4)2[RuIII(salpa)(N3)3]. These compounds could serve as building blocks for the construction of magnetic materials. In part 2, the reactivity of (PPh4)2[OsIII{N(H)CN}(L3)(CN)3] towards various electrophiles and nucleophiles has been investigated. Reactions of this compound with various alkyl amines and ammonium salts produce a series of guanidine-type complexes with the general formula, (PPh4)[OsIII{N(H)C(NH2)R}(L3)(CN)3] {R = CH3CH2NH; (CH3NH2)N; NH2; N(H)NH2; N(H)OH; N(CH3)OH}. The structures of some of these complexes have been determined by X-ray crystallography. Oxidation of [OsIII{N(H)C(NH2)(NHOH)}(L3)(CN)3]- leads to a nitrosyl complex [OsII(NO)(L3)(CN)3]-. On the other hand, oxidation of [OsIII{N(H)C(NH2)(NHNH2)}(L3)(CN)3]- by O2 or H2O2 leads to a formamidine complex, [OsIII(NH2C=NH)(L3)(CN)3]-. In part 3, a series of polynuclear complexes based on the building blocks [RuIII(Q)2(CN)2]-, [RuIII(CN-L1)(CN)3]2- and [RuIII(L1)(N3)3]2- have been synthesized. Reactions of these complexes with various 3d metals give a number of polynuclear complexes, including {[RuIII(Q)2](μ-CN)2[MnIII(salchda)]}n, {[RuIII(Q)2(CN)]2(μ-CN)2[CuII(cyclam)]}, {[RuIII(Q)2(CN)]2(μ-CN)2[NiII(cyclam)]}n, [RuIII(Q)(CN)2]n{[RuIII(Q)2](μ-CN)2[NiII(cyclen)]}n, [RuIII(Q)2(CN)]2(μ-CN)2- [MnII(DMF)2(Cl)]}n, {[RuIII(Q)2(CN)]2(μ-CN)2[MnII(MeOH)4]}, {[RuIII(Q)2(CN)]2(μ-CN)2- [CoII(DMF)2(Cl)]}n, {[RuIII(Q)2(CN)]2(μ-CN)2[CoII(MeOH)4]}, [RuIII(CN-L1)(μ-CN)3- [MnII(MeOH)3]n2nMeOH, [RuIII(CN-L1)(μ-CN)3[CoII(MeOH)3]n2nMeOH, {[RuIII(CN-L1)(CN)](μ-CN)2[MnII(L)]}n, {[RuIII(CN-L1)(CN)](μ-CN)2[NiII(cyclen)]}2, {[RuIII(CN-L1)(CN)](μ-CN)2[MnII(bpy) (MeOH)][RuIII(CN-L1)](μ-CN)3][MnII(bpy)2]}2, {[Ru(L1)(MeOH)](μ1,3-N3)(μ-N)[Ru(L1)][Co(MeOH)](μ-MeO)(μ3-MeO)}2 and {[Ru(L1)(MeOH)](μ-N3)(μ-N)[Ru(L1)][Ni(MeOH)](μ-MeO)(μ3-MeO)}2. The structures of these complexes have been determined by X-ray crystallography and their magnetic properties have been investigated. In part 4, reaction of [RuIII(salchda)(H2O)2](PF6) (4.1) with ethylamine, cyclohexylamine, isopropylamine and benzylamine under argon in acetone or ethanol gives a series of bis(amine)ruthenium(III) compounds. However, reaction of 4.1 with these amines in acetonitrile generates the bis(amidine) products, where the amidine ligands are formed by nucleophilic addition of amine to coordinate nitrile. Refluxing a solution of 4.1 and benzylamine or 2-aminomethylenepyridine in ethanol leads to the compounds [RuIII(salchda)(NHC(NHCH2Ph)Ph)2](PF6) or [RuIII(salchda) (NHC(NHCH2py)py)2](PF6), respectively, in which the axial amidine ligands are formed from two amines via amine-amine coupling. Reaction of 4.1 with pyrrolidine in ethanol produces a bis(imine) product, [RuIII(salchda) (NC4H7)2](PF6), where the axial ligands 1-pyroline are formed by oxidative dehydrogenation of pyrrolidine by air upon bonding to ruthenium(III).
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