La Spectrométrie de Masse à source Plasma à Couplage Inductif s'impose comme la technique de spectrométrie de masse la plus répandue en analyse inorganique pour mesurer la concentration d'un isotope donné ou des rapports isotopiques. Le problème des interférences spectroscopiques, inhérent à cette technique, trouve une solution dans l'utilisation de dispositifs de réaction. Une résolution in situ des interférences est en effet rendue possible par l'injection, dans la cellule de réaction, d'un gaz judicieusement choisi. La compréhension de la chimie des interactions ions-molécules en phase gazeuse est cependant primordiale pour en optimiser l'efficacité. Une connaissance précise des conditions expérimentales dans la zone de réaction en fonction des paramètres instrumentaux s'avère ainsi cruciale pour interpréter les réactivités observées. Cette étude préliminaire est ensuite mise à profit dans le cadre de la résolution de deux interférences, caractéristiques au domaine du nucléaire. / Inductively Coupled Plasma Mass Spectrometry emerged as the most widespread mass spectrometry technique in inorganic analytical chemistry for determining the concentration of a given isotope or an isotope ratio. The problem of spectroscopic interferences, inherent to this technique, finds a solution through the use of reaction cell devices. An in situ interference removal is feasible with the addition of a well selected gas in the cell. The understanding of the chemistry of ions-molecules interactions in the gas phase is however fundamental to optimize the efficiency of such devices. An accurate knowledge of experimental conditions in the reaction zone according to instrumental parameters appears crucial in order to interpret observed reactivities. This preliminary study is then used for the resolution of two nuclear field characteristic interferences.

Carbazole-bis(oxazoline) (Czx) lanthanide dialkyl, CzxLn(CH2SiMe3)2, and dichloride CzxLnCl2(THF)n, complexes were synthesized by protonolysis and salt metathesis protocols. The X-ray crystal structures of CzxLn(CH2SiMe3)2 (Ln = Er and Yb) and CzxLnCl2(THF) (Ln = Y, Er and Yb) were determined. The carbazole-bis(oxazoline) ancillary ligand provides high stability but relatively low activity in some reactions for the corresponding lanthanide complexes, possibly due to steric crowding caused by the dimethyl groups on the oxazoline ring. The synthesis of a series of divalent ytterbium monohalide complexes, CzxYbX(THF)2 (X = I, Cl) or CzxYbI(DME) was achieved by salt metathesis or sodium amalgam reduction methods. The salt metathesis reaction of CzxYbI(THF)2 with Li(CHSiMe3)2 or NaN(SiMe3)2 gave the corresponding divalent ytterbium alkyl and amide complexes, CzxYb[CH(SiMe3)2](THF) or CzxYb[N(SiMe3)2](THF), respectively. The solution behaviour of CzxYbI(THF)2 was investigated via variable temperature NMR spectroscopy and supported a dynamic process involving dissociation of THF at, or above, 280K. Similar dynamic solution behaviour was found in other divalent ytterbium complexes as well. Reaction of 2,2’-bipyridine with CzxYbI(THF)2, afforded a trivalent ytterbium complex with a coordinated bipyridyl radical anion illustrating that the divalent complex is a strong, one electron reducing agent. Despite this, treatment of CzxYbI(THF)2 with LiCH2SiMe3 gave a trivalent ytterbium dialkyl complex, CzxYb(CH2SiMe3)2, also prepared by salt metathesis starting from CzxYbCl2(THF) and LiCH2SiMe3. Reaction of the trivalent ytterbium dialkyl complex, CzxYb(CH2SiMe3)2, with a primary aryl phosphine, ArPH2, (Ar = Mes, Is), unexpectedly formed the divalent ytterbium secondary phosphides, CzxYb(PHAr)(THF)2. The same ytterbium phosphide complexes were also prepared by salt metathesis starting from either the divalent CzxYbI(THF)2 or the trivalent CzxYbCl2(THF) complexes. Non-reducible lanthanide dichloride complexes, CzxLnCl2(THF) (Ln = Sc, Y, Er) reacted with sodium aryl phosphides (NaPHAr) to generate the lanthanide mono(secondary phosphide) complexes, CzxLnCl(PHAr)(THF). / Graduate

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This dissertation focuses on the exploratory synthesis of compounds that contain R6ZI12 (R= Ce, Gd, Er; Z=Mn, Fe, Co, C2) clusters with the goal of finding magnetically interesting compounds. Several new compounds were made via high temperature, solid state methods and structurally characterized using x-ray diffraction. Compounds that contain isolated clusters were studied in order to understand the magnetic coupling between lanthanide atoms. The exploration of transition metal centered clusters resulted in the discovery of two new structure types, CsR(R6CoI12)2 (R=Gd and Er) and (CeI)0.26(Ce6MnI9)2. The xray crystal structure of CsEr(Er6CoI12)2 was solved in the Pa3 – space group with the cell length 18.063(2) Å at 250K (Z = 4, R1 [I>2σ(I)] = 0.0459). (CeI)0.26(Ce6MnI9)2 was made by combining KI, CeI3, MnI2 and Ce metal and heating to 850°C for 500 hrs. The single crystal x-ray structure for (CeI)0.26(Ce6MnI9)2 was solved in the trigonal, P3 – space group with lattice parameters of a = 11.695(1) Å c = 10.8591(2) Å (Z = 2, R1 [I>2σ(I)] = 0.0895). The magnetic susceptibilities of hexanuclear gadolinium clusters in the compounds Gd(Gd6ZI12) (Z = Co, Fe or Mn), CaxGd1-x(Gd6MnI12) and CsGd(Gd6CoI12)2 are reported. The single-crystal structure of Gd(Gd6CoI12) and CaxGd1-x(Gd6MnI12) are reported here as well. The compound with a closed shell of cluster bonding electrons, Gd(Gd6CoI12), exhibits the effects of antiferromagnetic coupling over the entire range of temperatures measured (4 - 300 K). Clusters with unpaired, delocalized cluster bonding electrons (CBEs) exhibit enhanced susceptibilities consistent with strong ferromagnetic coupling, except at lower temperatures (less than 30 K) where intercluster antiferromagnetic coupling suppresses the susceptibilities. Four new compounds containing Gd6C2 clusters have been found: Gd6C2I11, Gd(Gd6C2I12), CsGd(Gd6C2I12)2 and Cs(Gd6C2I12). Gd6C2I11 and Cs(Gd6C2I12) crystallized in the P1 space group while Gd(Gd6C2I12) and CsGd(Gd6C2I12)2 crystallized in the R3 and Pa3 space groups respectively. The magnetic susceptibility data for Cs(Gd6C2I12) indicate strong intracluster ferromagnetic coupling, but antiferromagnetic coupling suppresses the susceptibility below 150 K. DFT calculations on CsGd6C2I12 and molecular models indicate that the magnetic coupling between the basal Gd atoms is stronger than the magnetic coupling involving the axial Gd atoms in the distorted clusters.

Polynuclear lanthanide complexes have attracted increasing interest in coordination and materials chemistry as they generally possess aesthetically pleasing molecular structures and display interesting properties possibly for useful chemical and materials applications. The work described herein concerned with the exploratory synthesis, structural characterization, and property investigation of a number of polynuclear lanthanide and silver complexes with selected organic ligands. Details of this thesis work are summarized in the following chapters: Chapter 1 offers a background of the research, with an emphasis on lanthanide-containing compounds and polynuclear silver complexes. Synthetic methodologies, novel structural characteristics, and interesting physical properties toward possible applications are surveyed in order to convey the justification of this thesis work. Chapter 2 describes the design and synthesis, structural characterization of a series of dinuclear lanthanide complexes with 1-(2-pyridylazo)-2-naphthol. The photophysical properties of these complexes pertinent to optical-limiting applications are evaluated. Chapter 3 details the halide-templated assembly of dodecanuclear and pentadecanuclear lanthanide hydroxide complexes featuring histidine as supporting ligand via the ligand-controlled hydrolysis. Salient structural features of these complexes are discussed. Chapter 4 reports the synthesis, structural characterization, and spectroscopic studies of the giant polynuclear lanthanide complexes containing a 60-metal cluster core when threonine was used as the supporting ligand. Carbonate has been identified as a novel anionic template in these clusters. These Ln60 cluster complexes feature a sodalite cage structure with 24 vertex-sharing cubane-like [Ln₄(μ₃-OH) ₄]⁸⁺ units. Their magnetic and optical properties are measured and discussed. Chapter 5 describes the unexpected discovery of a polynuclear silver complex with histidine, first isolated from the reaction of a halide-containing polynuclear lanthanide hydroxide complex and then rationally prepared by using silver nitrate and histidine. A series of analogous silver complexes with other amino acids have subsequently prepared and structurally characterized. Chapter 6 details two silver-amino acid helicates composed of individual helical coordination polymers. Optically pure helicates were obtained by using enantiomerically pure amino acids. While silver-glutamate possesses a double-helical structure, silver-aspartate displays an unprecedented six-strand helical structure. Chapter 7 summarizes the results presented in Chapters 2-6 and elaborates on some future research directions toward which each of these projects may be heading.

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The study of biological analytes in their native environment is a major challenge for biochemistry and molecular biology.  Luminesce spectroscopy is well suited for this task due to its non-invasiveness, high spatial and temporal resolution, and high signal to noise ratio. This thesis describes the development and applications of Ln-based luminescent probes for detecting small molecules and enzymes.  Specifically the probes presented are based on coumarin sensitizers coupled to a DO3A chelated LnIII center. The 1st generation of these probes employ 7-OH coumarins, caged at the 7-O position (Chapter 2). By use of p-pinacolatoboron benzyl or p-methoxybenzyl cages, this design allowed the construction of ratiometric EuIII-based probes capable of detecting the reactive oxygen species H2O2, NO and ONOO−. The second and third part of the thesis describes a further improvement of the design (Chapters 3 and 4). By employing caged coumarin precursors EuIII and TbIII-based probes were developed for a variety of different analytes (F−, Pd0, H2O2, β-galactosidase, β-glucosidase, α-mannosidase and phosphatase). Most of these probes displayed excellent turn-on responses when treated with their respective analytes. Furthermore they could be used for detecting multiple analytes simultaneously (Chapter 4). By use of one Eu-based and another Tb-based probe, the simultaneous detection of two analytes was possible. This could further be extended to simultaneous three analyte detection by the additional employment of an organic coumarin-based probe. The last part of the thesis (Chapter 5) describes protocols for the rapid and efficient access to triazole-linked lanthanide-antenna complexes by use of the copper-catalyzed azide-alkyne cycloaddition reaction. For robust substrates, microwave heating at 100 °C enabled rapid (15-60 min) access to various lanthanide complexes, which could be isolated via simple precipitation. Using these conditions pure bi- and tri-homometallic lanthanide complexes could be prepared. A second protocol, for substrates carrying sensitive functionalities was also developed. The application of catalytic amounts of CuOAc, BimPy2 ligand, and a large excess of NaAsc afforded a variety of lanthanide complexes, among them caged responsive probes, in moderate to good yields.

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