This thesis describes the synthesis, structure and reactivity of singly bridged dinuclear Group 11 metal complexes, supported by N-heterocyclic carbene (NHC) ligands. These complexes include dinuclear copper(I) complexes that demonstrate three-center, two-electron bonding with short intermetallic distances. In the first part of this study, a hydride-bridged dicopper cation, {[(IDipp)Cu]2(μ-H)}+ BF4–, which adopts a bent arrangement about the hydride was isolated. It undergoes facile methanolysis, readily reacts with carbon dioxide to afford a (κ2-formate)-bridged dicopper species, and coordinates carbon monoxide reversibly to form a carbonyl adduct. The [(LCu)2H]+ cation also inserts phenylacetylene to afford a gem-dicopper vinyl cation, a rare example of the insertion of carbon-carbon multiple bonds into a copper hydride. The second part of this thesis describes the synthesis and structural characterization of the first boryl-bridged dicopper cation {[(SIDipp)Cu]2(μ-B(O2C6H4)}+ BF4–. The solid state structure shows a bent arrangement about the boryl with a short intermetallic distance of 2.4082(2) Å. The boryl-bridged dicopper cation deprotonates phenylacetylene to form a phenylacetylide dicopper complex. It also readily reacts with methanol to form the hydride-bridged dicopper cation. Density functional theory (DFT) calculations were applied to give further insight into the nature of the metal–boron bonds in comparison to the mononuclear analogue. The two electrons contributed by the bridging boryl are shared between the boron and the two copper centers in the [(LCu)2B]+ core. This three-center, two-electron bonding orbital is lower-lying in energy in comparison to the Cu−B σ-bonding molecular orbital in the mononuclear analogue, consistent with a less nucleophilic Cu–B bond. The NHC ligand also stabilizes an isoleptic series of dinuclear μ-fluoro cations of copper(I), silver(I), and gold(I). In these complexes, a single fluoride acts as the sole bridging ligand between the two group 11 metal centers of the form [(LM)2(μ-F)]+. All three cations are highly sensitive to adventitious moisture, readily forming the hydroxide-bridged dinuclear cations. The gold(I) complex is the most reactive. It activates the C-Cl bonds of CD2Cl2 and adds rapidly across an allene C=C bond to form an allylic C–F bond, and a vinyl anion bound asymmetrically to the two gold(I) centers.

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The objective of my MSc thesis is to study the self-assembly process of macrocyclic complexes, as well as the properties that affect the obtained supramolecular architectures. The possibility of substrate recognition within the cavity of these complexes is also of interest. Preparation of three new ligands based on the triazole-pyridine chelating units connected through variable spacer groups, as well as the complexes formed with octahedral metal ions, are described herein. The first ligand contained a naphthalene spacer region, which was longer than the previously examined xylene spacer. This extension increases the distance between metal ions in the complex, as well as the size of the cavity. More work is required to obtain the unsaturated double-stranded complex, which could potentially bind substrate molecules within its cavity. The triple-stranded saturated complexes with [Fe(H2O)6](BF4)2 and [Ni(H2O)6](BF4)2 both gave insight into the process of self-assembly. The next two ligands were designed to probe the effect that increasing the length of an aliphatic spacer had on complex self-assembly. Both ethyl and propyl spacer units had been previously studied, so butyl and pentyl spacer groups were the natural next step to analyze. The length of the alkyl spacer was found to be very important in the nature of the obtained complex. As the length of the alkyl chain, and the corresponding flexibility increased, so too did the complexity of the resulting supramolecular architectures. / Thesis (Master, Chemistry) -- Queen's University, 2013-09-03 12:21:39.581

Phosphoryl transfer reactions are vital to life. In response to the slow intrinsic rates of phosphoryl transfer, Nature has evolved a series of enzymes designed to accelerate these reactions and allow them to occur at biologically relevant rates. These metallo-enzymes are largely characterized by bi- or tri-nuclear active sites with effective dielectric constants that more closely resemble those of organic solvents than water. This project was designed to better understand the mechanisms by which metalloenzymes cleave phosphodiesters with poor leaving groups. The stability of the phosphodiester is central to the storage of genetic information in DNA and RNA. The cleavage of a series of more reactive RNA models, 2-hydroxylpropyl aryl phosphates 1a-g, catalyzed by a dinuclear Zn(II)2 complex of 53 in methanol was explored. A solution of 53:Zn(II)2:(-OCH3) was observed to accelerate the decomposition of 1a-g with rates that were 10^11-10^12-fold greater than the methoxidepromoted reaction at ss pH 9.47, approaching rate accelerations achieved by natural enzymes. The remarkable activity of 53:Zn(II)2:(-OCH3) and 36:Zn(II)2:(-OCH3) towards the cleavage of 1a-g probed the study of the decomposition of diribonucleotides(3'->€™ 5')UpU and (3'->€™ 5'€™)ApC in methanol. The 53:Zn(II)2:(-OCH3)- and 36:Zn(II)2:(-OCH3)-catalyzed decomposition of UpU achieved k2 values of 1.21 ± 0.17 and (7.04 ± 0.99) x 10^-2 M^-1s^-1. The reactivity of ApC in the presence of these systems was unimpressive, however Zn(II) ions in ethanol resulted in the isomerization of 3'->€™ 5'€™)ApC to (2'->™ 5'€™)ApC providing support for the existence of a pentacoordinate phosphorane intermediate. The pentacoordinate phosphorane was further explored through the reaction of 36:Zn(II)2:(-OCH3) with the cyclic phosphate 58 and 2-hydroxylpropyl methyl phosphate (59). In the presence of 36:Zn(II)2:(-OCH3) the rate of isomerization of 59/59a (kobs = (4.7 ± 0.5) x 10^-3 s^-1) exceeded that of expulsion of the methoxy group (kobs = 1.62 x 10^-3 s^-1), thus confirming the existence of a pentacoordinate phosphorane intermediate (60)and providing support for a two-step phosphodiester cleavage reaction. The catalytic efficiency of 36:Zn(II)2:(-OCH3) towards the cleavage of stable phosphodiesters probed its application towards the decomposition of dimethyl phosphate (2) in methanol-d4. The exchange of OCH3 for OCD3 occurred with kcatmax = (2.27 ± 0.03) x 10^-6 s^-1. / Thesis (Master, Chemistry) -- Queen's University, 2008-09-12 13:09:42.427

This thesis describes the synthesis and characterisation of a variety of acetylide-bridged di- and trinuclear ruthenium acetylide complexes that were prepared in a controlled fashion, and the preparation and characterisation of the ruthenium(II) complexes required for these stepwise reactions. These precursor complexes, or building blocks, include dimethyl-, acetylidomethyl-, and bis(acetylido)ruthenium(II) complexes. An introduction to metal acetylide chemistry is presented in Chapter 1. The previous research in this area is briefly reviewed, and the potential applications of these complexes are highlighted. The primary aims of this course of work are outlined, namely, to develop a controlled synthetic approach to the synthesis of oligonuclear ruthenium acetylide complexes. The synthetic strategies for this aim are introduced in Chapter 2, and the synthetic routes to cis and trans-Ru(CH3)2(dmpe)2 (25/23) and cis and trans-Ru(CH3)2(depe)2 (26/24) are described. Characterisation of the novel, synthetically important trans-Ru(CH3)2(dmpe)2 (23) is completed by an examination of its X-Ray crystallographic structure. Chapter 3 describes the thermal and photochemical metathesis reactions of trans-Ru(CH3)2(dmpe)2 (23) with terminal acetylenes, and the preparation of a variety of acetylidomethylruthenium(II) complexes, trans-Ru(CH3)(C≡CR)(dmpe)2 (R = Ph (30), tBu (31), SiMe3 (32), C6H4-4-tBu (33), C6H3-3,5-tBu2 (34), C6H4-4-C≡CH (35), C6H4-4-OCH3 (36), C6H4-4-CH3 (37), C6H3-3,5-(CF3)2 (38)). The characterisation of these complexes by NMR spectroscopy, IR spectroscopy and X-Ray crystallography is presented. A clean and high yielding synthesis of the synthetically significant unsymmetrical bis(acetylido)ruthenium(II) complexes was developed via the reaction of an acetylidomethylruthenium(II) complex with an excess of a second terminal alkyne in a mixture of methanol and benzene. The characterisation of the novel complexes trans-Ru(C≡CR)(C≡CR′)(dmpe)2 (R = Ph, R′ = tBu (40), SiMe3 (41), C6H4-4-C≡CH (44); R = tBu, R′ = SiMe3 (42), C6H4-4-C≡CH (43), C6H4-4-tBu (45), C6H3-3,5-tBu2 (46)) by NMR and IR spectroscopy, mass spectrometry and X-Ray crystallography is described in Chapter 4. Additionally, Chapter 4 describes the synthesis and characterisation of symmetrical bis(acetylido)ruthenium(II) complexes, and a number of organic butenyne compounds, which were observed as by-products from the attempted synthesis of several of the bis(acetylido)ruthenium(II) complexes. Dinuclear ruthenium(II) complexes were prepared by the reaction of trans-Ru(C≡CR)(C≡CC6H4-4-C≡CH)(dmpe)2 (R = tBu (43) or Ph (44)) with an acetylidomethylruthenium(II) complex in toluene and methanol. Both symmetrical and unsymmetical dinuclear complexes could be prepared in this way, and were characterised by a range of techniques including NMR spectroscopy, IR spectroscopy, mass spectrometry and X-Ray crystallography, and are described in Chapter 5. In addition, an electrochemical study of one of the dinuclear complexes was undertaken using cyclic voltammetry. The symmetrical trinuclear ruthenium(II) complexes, trans,trans,trans- (RC≡C)Ru(dmpe)2(μ-C≡CC6H4C≡C)Ru(depe)2(μ-C≡CC6H4C≡C)Ru(dmpe)2(C≡CR) (R = Ph (80), tBu (81), SiMe3 (82)) was prepared by the reaction of two equivalents of an acetylidomethylruthenium(II) complex with the symmetrical bis(acetylido)ruthenium(II) complex, trans-Ru(C≡CC6H4-4-C≡CH)2(depe)2 (54), in toluene and methanol. These syntheses, and the subsequent characterisation of the products are also reported in Chapter 5. The primary aim of this thesis, viz. the synthesis and characterisation of acetylide bridged di- and trinuclear ruthenium acetylide complexes in a controlled fashion, was successfully achieved. Suggestions for future work are described in Chapter 6.

This thesis describes the synthesis and characterisation of a variety of acetylide-bridged di- and trinuclear ruthenium acetylide complexes that were prepared in a controlled fashion, and the preparation and characterisation of the ruthenium(II) complexes required for these stepwise reactions. These precursor complexes, or building blocks, include dimethyl-, acetylidomethyl-, and bis(acetylido)ruthenium(II) complexes. An introduction to metal acetylide chemistry is presented in Chapter 1. The previous research in this area is briefly reviewed, and the potential applications of these complexes are highlighted. The primary aims of this course of work are outlined, namely, to develop a controlled synthetic approach to the synthesis of oligonuclear ruthenium acetylide complexes. The synthetic strategies for this aim are introduced in Chapter 2, and the synthetic routes to cis and trans-Ru(CH3)2(dmpe)2 (25/23) and cis and trans-Ru(CH3)2(depe)2 (26/24) are described. Characterisation of the novel, synthetically important trans-Ru(CH3)2(dmpe)2 (23) is completed by an examination of its X-Ray crystallographic structure. Chapter 3 describes the thermal and photochemical metathesis reactions of trans-Ru(CH3)2(dmpe)2 (23) with terminal acetylenes, and the preparation of a variety of acetylidomethylruthenium(II) complexes, trans-Ru(CH3)(C≡CR)(dmpe)2 (R = Ph (30), tBu (31), SiMe3 (32), C6H4-4-tBu (33), C6H3-3,5-tBu2 (34), C6H4-4-C≡CH (35), C6H4-4-OCH3 (36), C6H4-4-CH3 (37), C6H3-3,5-(CF3)2 (38)). The characterisation of these complexes by NMR spectroscopy, IR spectroscopy and X-Ray crystallography is presented. A clean and high yielding synthesis of the synthetically significant unsymmetrical bis(acetylido)ruthenium(II) complexes was developed via the reaction of an acetylidomethylruthenium(II) complex with an excess of a second terminal alkyne in a mixture of methanol and benzene. The characterisation of the novel complexes trans-Ru(C≡CR)(C≡CR′)(dmpe)2 (R = Ph, R′ = tBu (40), SiMe3 (41), C6H4-4-C≡CH (44); R = tBu, R′ = SiMe3 (42), C6H4-4-C≡CH (43), C6H4-4-tBu (45), C6H3-3,5-tBu2 (46)) by NMR and IR spectroscopy, mass spectrometry and X-Ray crystallography is described in Chapter 4. Additionally, Chapter 4 describes the synthesis and characterisation of symmetrical bis(acetylido)ruthenium(II) complexes, and a number of organic butenyne compounds, which were observed as by-products from the attempted synthesis of several of the bis(acetylido)ruthenium(II) complexes. Dinuclear ruthenium(II) complexes were prepared by the reaction of trans-Ru(C≡CR)(C≡CC6H4-4-C≡CH)(dmpe)2 (R = tBu (43) or Ph (44)) with an acetylidomethylruthenium(II) complex in toluene and methanol. Both symmetrical and unsymmetical dinuclear complexes could be prepared in this way, and were characterised by a range of techniques including NMR spectroscopy, IR spectroscopy, mass spectrometry and X-Ray crystallography, and are described in Chapter 5. In addition, an electrochemical study of one of the dinuclear complexes was undertaken using cyclic voltammetry. The symmetrical trinuclear ruthenium(II) complexes, trans,trans,trans- (RC≡C)Ru(dmpe)2(μ-C≡CC6H4C≡C)Ru(depe)2(μ-C≡CC6H4C≡C)Ru(dmpe)2(C≡CR) (R = Ph (80), tBu (81), SiMe3 (82)) was prepared by the reaction of two equivalents of an acetylidomethylruthenium(II) complex with the symmetrical bis(acetylido)ruthenium(II) complex, trans-Ru(C≡CC6H4-4-C≡CH)2(depe)2 (54), in toluene and methanol. These syntheses, and the subsequent characterisation of the products are also reported in Chapter 5. The primary aim of this thesis, viz. the synthesis and characterisation of acetylide bridged di- and trinuclear ruthenium acetylide complexes in a controlled fashion, was successfully achieved. Suggestions for future work are described in Chapter 6.

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No description available.

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第22702号 / 工博第4749号 / 新制||工||1742(附属図書館) / 京都大学大学院工学研究科物質エネルギー化学専攻 / (主査)教授 大江 浩一, 教授 近藤 輝幸, 教授 中尾 佳亮 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM

Heterodinuclear and homodinuclear metal complexes with a direct metal-metal interaction offer the potential for unique catalysis due to cooperativity effects that impact reaction mechanisms, reactivity, and selectivity. Quantum-chemical density functional theory (DFT) calculations can directly examine the origin of dinuclear reactivity and selectivity effects. Chapter 1 provides a short overview of heterodinuclear and homodinuclear catalysts that have been experimentally and computationally examined. Chapter 2 reports our study using DFT methods to understand the mechanism and reactivity of a heterodinuclear Co-Zr catalyst with phosphinoamide ligands that catalyzes a Kumada coupling between alkyl halides and alkyl Grignards. Chapter 3 reports DFT calculations that determine the mechanism for homodinuclear Ni-Ni promoted intramolecular vinylidene"“alkene cyclization.