Au(I) catalysis has recently emerged as a powerful tool for the realization of a broad range of organic transformations. Despite this rapid development, attaining selectivity and maintaining catalyst stability remain significant challenges. Rational ligand design, such as the employment of NHC or TA ligands, has been used to confront these issues. This thesis focuses on the use of Au(I) catalysts bearing these ligands for the selective hydroalkynylation of enol ethers. By employing a TA-Au stabilized catalyst, [(OAr)3PAu(TA-H)]OTf, the intermolecular hydroalkynylation of enol ethers, a substrate that is well-known to promote decomposition of the gold cation, was efficiently achieved. As an expansion of this reaction, the NHC-Au catalyst, IPrAuNTf2, was utilized in a multicomponent system to promote the tandem hydroalkynylation of enol ethers formed in-situ via the cycloisomerization of alkynols. Further exploration of this tandem reaction revealed that IPrAuNTf2 catalyzes a cascade ring-expansion of the alkynylated heterocycles to form oxepines. The mechanistic and synthetic insight obtained from these developed reactions has the potential to be applied towards future studies in gold catalysis.

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Alkali (A) and alkaline earth (AE) metals can form carbides and intercalated graphites with carbon. The carbides mostly represent acetylides which are salt-like compounds composed of C22− dumbbell anions and metal cations. Both the acetylide carbides and intercalated graphites are technologically important. Superconductivity has been observed in several intercalated graphites such as KC8 and CaC6. Li intercalated graphites are a major ingredient in Li ion batteries. CaC2 is an important commodity for producing acetylene and the fertilizer CaCN2. In spite of the extensive research on A–C and AE–C compounds, phase diagrams are largely unknown. The thermodynamic and kinetic properties of both carbides and intercalalated graphites are discussed controversially. Recent computational studies indicated that well-known carbides, like CaC2 and BaC2, are thermodynamically unstable. Additionally, computational studies predicted that acetylide carbides will generally form novel polymeric carbides (polycarbides) at high pressures. This thesis is intended to check the validity of theoretical predictions and to shed light on the complicated phase diagrams of the Li–C and the Ca–C systems. The Li–C and the Ca–C systems were investigated using well-controllable metal hydride–graphite reactions. Concerning the Li–C system, relative stabilities of the metastable lithium graphite intercalation compounds (Li-GICs) of stages I, IIa, IIb, III, IV and Id were studied close to the competing formation of the thermodynamically stable Li2C2. The stage IIa showed distinguished thermal stability. The phase Id showed thermodynamic stability and hence, was included in the Li–C phase diagram. In the Ca–C system, results from CaH2–graphite reactions indicate compositional variations between polymorphs I, II and III. The formation of CaC2  I was favored  only  at  1100  ◦C or  higher  temperature  and  with  excess calcium, which speculates phase I as carbon deficient CaC2−δ . To explore the potential existence of polycarbides, the acetylide carbides Li2C2 and CaC2 were investigated under various pressure and temperature conditions, employing diamond anvil cells for in situ studies and multi anvil techniques for large volume synthesis. The products were characterized by a combination of diffraction and spectroscopy techniques. For both Li2C2 and CaC2, a pressure induced structural transformation was observed at relatively low pressures (10–15 GPa), which was followed by an irreversible amorphization at higher pressures (25–30 GPa). For Li2C2 the structure of the high pressure phase prior to amorphization could be elucidated. The ground state with an antifluorite Immm structure (coordination number (CN) for C22− dumbbells = 8) transforms to a phase with an anticotunnite Pnma structure (CN for C22− dumbbells = 9). Polycarbides, as predicted from theory, could not be obtained. / <p>At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 2: Manuscript.</p>

High-intensity light — for instance that from a laser — can be destructive, not only to the human eye, but also to equipment such as imaging sensors and optical communication devices. Therefore, effective protection against such light is desirable. A protection device should ideally have high transmission to non-damaging light, and should also be fast-acting in order to effectively stop high-intensity light. In working towards a protection device, there is a need to conduct fundamental research in order to understand the processes involved. One of the photophysical processes of special interest in the field of optical power limiting (OPL) is reverse saturable absorption, where a compound in an excited state absorbs light more strongly than it does in its ground state. In this work, several novel organoplatinum compounds for OPL, rationally designed to have a strong reverse saturable absorption, have been synthesized. The compounds have been analyzed using linear and nonlinear absorption spectroscopy, luminescence spectroscopy, and quantum chemistry calculations to gain further knowledge regarding their photophysical properties. In addition to this fundamental research, the absorption capabilities of some of these compounds indicate that they can be used for OPL applications. Consequently, compounds from these studies have been incorporated into a sol–gel glass that could be used in optical systems. / <p>Finansiellt stöd från Kempestiftelsen.</p>

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Le projet de recherche est centré sur le développement de nouvelles transformations catalysées par de l'or en chimie des ions N-acyliminiums. L'objectif de la première partie de ce projet est de développer une séquence 5-exo-dig intramoléculaire hydroalkoxylation/aza-Ferrier-Petasis réarrangement catalysée par l’or. Une deuxième partie du projet est consacrée à l'élaboration de la première alcynylation catalytique d'ions cycliques N-acyliminium utilisant N,O-acétals. Ce type de réaction est potentiellement une transformation importante, donnant naissance à des dérivés d'amines propargyliques. Ces derniers peuvent faire l’objet d’autres réactions conduisant à des produits naturels azotés ainsi qu’à certains analogues. Compte tenu de nos objectifs, l’intérêt principal est l'utilisation d’alkynes TMS en accord avec des complexes d'or qui ont été coordines avec des contre-ions faiblement nucléophiles. Pour élargir le champ de la catalyse basée sur l'or, il est important d'étendre la gamme de substrats et les groupes fonctionnels qui peuvent être activées par des complexes d'or. Une dernière partie est consacrée à la catalyse séquentielle qui favorise des processus catalytiques à plusieurs étapes. De cette manière, deux transformations catalytiques et fondamentalement différentes sont réalisées dans un même récipient. Ce travail nous a permis l’accès rapide et efficace à une famille de composes à structure complexe avec bons rendements. Par conséquent, il s'agit d'un sujet innovant en synthèse organique moderne qui a permis d’ouvrir la voie à de nouveaux projets. / The research project is centred on the development of new gold catalyzed transformations in N-acyliminium ion chemistry. The objective of our first part of the project is to develop an enantioselective gold-catalyzed 5 exo-dig intramolecular hydroalkoxylation/aza-Ferrier-Petasis rearrangement sequence. This sequence could give an asymmetric and atom economic expeditious access to the structure of hydropyrrolizidines, which are known to be potential biologically active compounds. A second part of the project is devoted to the development of the first catalytic alkynylation of cyclic N-acyliminium ions using N,O-acetals. This type of reaction is potentially an important transformation, giving rise to propargylic amine derivatives amenable to further interesting synthetic manipulations en route to nitrogen-containing natural products and some analogs. Considering our objectives, key features is the use of TMS alkynes in conjunction with gold complexes that have been paired with poorly nucleophilic counter-ions. To broaden the scope of catalysis based on gold, it is important to extend the range of substrates and functional groups that can be activated by gold complexes. A final section is devoted to the sequential catalysis which designs the promotion of catalytic multistep processes. In this way, two fundamentally distinct chemical transformations are catalytically promoted in a single flask. This research area allows the rapid and efficient reach of complex molecular frameworks with improved yields and resource efficiency. Therefore, this is an exciting theme in modern organic synthesis that has recently stimulated the report of numerous excellent contributions.

Chapter 1.<br />1-Ethynyl-2-phenyltetramethyldisilanes HCºCSiMe2SiMe2C6H4-p-X [X = NMe2(1.1), Me (1.2), H (1.3), Br (1.4), CF3 (1.5)] are accessible from ClSiMe2SiMe2Cl, BrMgC6H4X and HCºCMgBr in a two step Grignard reaction. The crystal structure of 1.1 as determined by single crystal X-ray crystallography exhibits a nearly planar PhNMe2 moiety and an unusual gauche array of the phenyl and the acetylene group with respect to rotation around the Si-Si-bond. Full geometry optimization (B3LYP/6- 31+G**) of the gas phase structures of 1.1 and 1.3 affords minima for the gauche and the trans rotational isomers, both being very close in energy with a rotational barrier of only 3 – 5 kJ/mol. Experimental and calculated (time-dependent DFT B3LYP/TZVP) UV absorption data of 1.1 – 1.5 show pronounced electronic interactions of the HCºC- and the C6H4X p-systems with the central Si-Si bond.<br /><br />Chapter 2.<br />A family of [( 5-Cp*)Ru( 6-arene)]+ (Cp* = C5Me5) sandwich complexes of 1- and 1,4-substituted phenyl and naphthyl systems are described along with the regioselectivities of the reactions under various conditions. Finally, the (h 5-Cp*) Ru+ arenophile was found to act as a gate to the flow of electrons between para-substituted termini. When it is complexed onto the phenyl or A naphthyl ring, the gate is closed. On the contrary, when it is complexed onto the B naphthyl ring, the gate is open.<br /><br />Chapter 3.<br />Regioselective complexation reactions of the organoiron acetylide derivatives (h 2- dppe)(h 5-Cp*)Fe-C C-Ar (Ar = phenyl, 1-naphthyl; dppe = 1,2- bis(diphenylphosphino)ethane) with [(h 5-Cp*Ru(CH3CN)3][PF6] to afford heterobimetallic complexes formulated as [(h 2-dppe)(h 5-Cp*)Fe-C C-{(h 6-Ar)Ru(h 5- Cp*)}][PF6], were achieved. In the case of the FeII-RuII 1-naphthyl derivative, the (h 5-Cp*)Ru+ arenophile was complexed both onto the substituted ring and free rings of the acetylide 1-naphthyl linker. The first redox-driven h 6-h 6 inter-ring haptotropic migration of the (h 5-Cp*)Ru+ moeity was shown to occur. Crystal structures of all of the seven new iron acetylenes were resolved, including both haptotropomers of the naphthyl compound.<br /><br />Chapter 4.<br />The diorganoiron [{(h2-dpppe)(h5-Cp*)Fe-CC-}2(1,4-naphthyl)] (4.12) was synthesized in good yield in two steps via the vinylidene, and oxidation led to the mixed valence (MV) and iron(III)-iron(III) species in good to excellent yields. This exhaustive empirical study on the family of complexes 4.12[PF6]n (n = 0,1,2) includes a crystal structure for the case in which n = 2. This work clearly establishes good electronic and magnetic communication between the iron centers across the bis(ethynyl)naphthalene bridge. All empirical measurements of these naphthyl compounds reveal that their properties fall between those of known phenyl and anthracenyl derivatives. In some cases, the naphthyl derivative behaves as an average of the phenyl and anthracenyl complexes. For example, the comproportionation constant of the naphthyl species falls at the midpoint between those for the phenyl and anthracenyl compounds. The same is true for the UV absorption maxima in all three oxidation states (Fe[II]- Fe[II], MV, and Fe[III]- Fe[III]). The large electronic (2043 cm-1) and magnetic (-526 cm-1) coupling constants were determined via NIR spectroscopy and SQUID magnetometry, respectively. As for the heterotrinuclear species, the iron(II) acetylene, 4.14B[PF6] [{Cp*(dppe)Fe-C C}2-(h 6 – [1,4-napthyl])RuCp*](PF6), [Cp* = h 5 - C5Me5; Fe = FeII] was prepared in high yields with an adapted, regioselective synthesis via the trinuclear vinylidene. Complete characterization, including a crystal structure, of this sandwich complex reveals that the arenophile perturbs the organoiron ligand more in the bis(iron) than in the previously reported mono(iron) case.