This thesis describes the synthesis, structure, equilibriaand other properties of novel thallium(III) monomeric andplatinum-bonded complexes with nitrogen donor ligandsethylenediamine, diethylenetriamine, triethylenetetramine,porphyrin, 2,2'-bipyridine and 1,10-phenanthroline in solutionand in solid. The existence of three complexes withthe general formula[Tl(en)n]3+(n = 1-3) and their overall stability constantshave been established in pyridine. All three complexes wereidentified by their205Tl and1H NMR chemical shifts and205Tl-1H coupling constants. The formation process of thecomplexes was followed by1H NMR spectroscopy. The crystal structure of[Tl(en)3](ClO4)3was determined; the thallium(III) ion isN-coordinated in a distorted octahedral geometry. Two [Tl(dien)n]3+(n = 1-2) complexes were proved to exist insolution and the structure of the bis-complex [Tl(dien)2]2+inu-facialisomers was determined in solid. In addition,crystal structures of [Tl(en)2CN](ClO4)2with cyanide bridging between two Tl(en)2units forming an infinite chain structure and of[Tl(tren)2(CN)2](ClO4) with a distorted pseudo-octahedral coordinationaround thallium were determined. Thallium(III) complexes with2,2'-bipyridine and 1,10-phenanthroline have been studied inDMSO using205Tl,13C and1H NMR spectroscopy. In addition, aseven-coordinated thallium was found in the crystal structureof [Tl(bipy)3(dmso)](ClO4)3, and six-coordinated thallium in pseudo-octahedralgeometry in [Tl(phen)2Cl2](ClO4). The solvated complex [Tl(dmso)6]3+has been prepared using concentrated aqueoussolution of Tl(ClO4)3by a solvent replacement reaction in DMSO, and thewater-free solid compound [Tl(dmso)6](ClO4)3was crystallized from DMSO. The structure of thecomplex [Tl(dmso)6]3+is a regular octahedron with the Tl-O bonddistance 2.224(3) Å. It represents an easy and secure wayto introduce water-free Tl(III) into organic phase withoutreduction. Through several reactions, novel heteronuclear Pt-Tlcomplexes with the composition [(NC)5Pt-Tl(tpp)]2-, [(NC)5Pt-Tl(thpp)]2-, [(NC)5Pt-Tl(bipy)n](n = 1-2), [(NC)5Pt-Tl(en)n-1](n = 1-3) and [(NC)5Pt-Tl(phen)n](n = 1-2), have been synthesized in solution.Multinuclear NMR (195Pt,205Tl,13C and1H), Raman spectroscopy and X-ray diffraction dataare fully compatible with formation of unsupported Pt-Tl bondedcomplexes both in solution and in solid. The huge1J(195Pt-205Tl) spin-spin coupling constants (48-66 kHz) wereobserved by both195Pt and205Tl NMR spectroscopy in solution and they providea strong evidence of formation of the Pt-Tl bond in solution.In all six determined crystal structures of the Pt-Tl compoundsa very short Pt-Tl bond is found with distances2.6117(5)-2.6375(5) Å. The calculated values of Pt-Tlforce constants (1.38-1.91 N/cm) are characteristic for asingle metal-metal bond. In the Pt-Tl compounds, the oxidation state of the metalions is intermediate between the stable states PtII/PtIVand TlIII/TlI, respectively, and this is reflected by their195Pt and205Tl chemical shifts. It turns out that N-donorligands can really stabilize the Pt-Tl bond both in solutionand in solid. The character of the metal-metal bond anditstheoretical basis are discussed. <b>Keywords:</b>Thallium, Platinum, Cyanide, N-donor ligand,Metal-metal bond, Multinuclear NMR, Raman spectroscopy, X-raydiffraction, Equilibrium, Spin-spin coupling.

<p>This thesis describes the synthesis, structure, equilibriaand other properties of novel thallium(III) monomeric andplatinum-bonded complexes with nitrogen donor ligandsethylenediamine, diethylenetriamine, triethylenetetramine,porphyrin, 2,2'-bipyridine and 1,10-phenanthroline in solutionand in solid.</p><p>The existence of three complexes withthe general formula[Tl(en)_n]³⁺(n = 1-3) and their overall stability constantshave been established in pyridine. All three complexes wereidentified by their²⁰⁵Tl and¹H NMR chemical shifts and²⁰⁵Tl-¹H coupling constants. The formation process of thecomplexes was followed by¹H NMR spectroscopy. The crystal structure of[Tl(en)₃](ClO₄)₃was determined; the thallium(III) ion isN-coordinated in a distorted octahedral geometry. Two [Tl(dien)_n]³⁺(n = 1-2) complexes were proved to exist insolution and the structure of the bis-complex [Tl(dien)₂]²⁺in<i>u-facial</i>isomers was determined in solid. In addition,crystal structures of [Tl(en)₂CN](ClO₄)₂with cyanide bridging between two Tl(en)₂units forming an infinite chain structure and of[Tl(tren)₂(CN)₂](ClO₄) with a distorted pseudo-octahedral coordinationaround thallium were determined. Thallium(III) complexes with2,2'-bipyridine and 1,10-phenanthroline have been studied inDMSO using²⁰⁵Tl,¹³C and¹H NMR spectroscopy. In addition, aseven-coordinated thallium was found in the crystal structureof [Tl(bipy)₃(dmso)](ClO₄)₃, and six-coordinated thallium in pseudo-octahedralgeometry in [Tl(phen)₂Cl₂](ClO₄).</p><p>The solvated complex [Tl(dmso)₆]³⁺has been prepared using concentrated aqueoussolution of Tl(ClO₄)₃by a solvent replacement reaction in DMSO, and thewater-free solid compound [Tl(dmso)₆](ClO₄)₃was crystallized from DMSO. The structure of thecomplex [Tl(dmso)₆]³⁺is a regular octahedron with the Tl-O bonddistance 2.224(3) Å. It represents an easy and secure wayto introduce water-free Tl(III) into organic phase withoutreduction.</p><p>Through several reactions, novel heteronuclear Pt-Tlcomplexes with the composition [(NC)₅Pt-Tl(tpp)]^2-, [(NC)₅Pt-Tl(thpp)]^2-, [(NC)₅Pt-Tl(bipy)_n](n = 1-2), [(NC)₅Pt-Tl(en)_n-1](n = 1-3) and [(NC)₅Pt-Tl(phen)_n](n = 1-2), have been synthesized in solution.Multinuclear NMR (¹⁹⁵Pt,²⁰⁵Tl,¹³C and¹H), Raman spectroscopy and X-ray diffraction dataare fully compatible with formation of unsupported Pt-Tl bondedcomplexes both in solution and in solid. The huge¹J(¹⁹⁵Pt-²⁰⁵Tl) spin-spin coupling constants (48-66 kHz) wereobserved by both¹⁹⁵Pt and²⁰⁵Tl NMR spectroscopy in solution and they providea strong evidence of formation of the Pt-Tl bond in solution.In all six determined crystal structures of the Pt-Tl compoundsa very short Pt-Tl bond is found with distances2.6117(5)-2.6375(5) Å. The calculated values of Pt-Tlforce constants (1.38-1.91 N/cm) are characteristic for asingle metal-metal bond.</p><p>In the Pt-Tl compounds, the oxidation state of the metalions is intermediate between the stable states Pt^II/Pt^IVand Tl^III/Tl^I, respectively, and this is reflected by their¹⁹⁵Pt and²⁰⁵Tl chemical shifts. It turns out that N-donorligands can really stabilize the Pt-Tl bond both in solutionand in solid. The character of the metal-metal bond anditstheoretical basis are discussed.</p><p><b>Keywords:</b>Thallium, Platinum, Cyanide, N-donor ligand,Metal-metal bond, Multinuclear NMR, Raman spectroscopy, X-raydiffraction, Equilibrium, Spin-spin coupling.</p>