Studies of Low Oxidation State Group 14 Complexes and Their Reactivity Towards Small Molecules

Studies of Low Oxidation State Group 14 Complexes and Their Reactivity Towards Small Molecules
Author: Jiaye Li
Publisher:
Total Pages: 410
Release: 2013
Genre:
ISBN:

This thesis concerns research into the synthesis of low oxidation state group 14 complexes and their reactivity towards small molecule activation. A number of group 14 complexes in the +1 or +2 oxidation states have been synthesized. These include the first singly-bonded amido germanium(I) complex (amido-digermyne, [LGeGeL], L = {N(MeAr)(SiMe3)}, MeAr = C6H2{C(H)Ph2}2Me-2,6,4), amido group 14 metal(II) halide complexes, e.g. [LECl] (E = Ge, Sn or Pb, SiR3 = SiMe3, SiPh2Me or SiPh3), and amido silicon(IV) halide complexes, e.g. [LSiX3] (X = Cl or Br). The reactivity of the amido digermyne towards a variety of small molecules, e.g. H2, CO2, N2O, CS2, alkynes, etc., has been examined. In addition, the synthesis of "one-coordinate" group 14 metal(II) monocationic complexes (e.g. [LE]+[PF]-, E = Ge or Sn, PF = [Al{OC(CF3)3}4]- ) has been investigated and their reactivity towards Lewis base molecules has been examined. Work included in this thesis can be divided into six chapters. Chapter 1 introduces recent developments in main group chemistry, bonding in low oxidation state main group compounds, kinetic stabilization, and the "inert pair" effect. Some examples of low oxidation state main group complexes are described.Chapter 2 introduces the synthesis and coordination chemistry of a series of bulky secondary amines, [(MeAr)(SiR3)NH], [(iPrAr)(SiMe3)NH] (iPrAr = C6H2{C(H)Ph2}2iPr-2,6,4) and [(tBuAr)(SiR3)NH] (tBuAr = C6H2{C(H)Ph2}2tBu-2,6,4). Subsequently, the chapter discusses the synthesis of amido group 14 metal(II) halide complexes, e.g. [LECl] (E = Ge, Sn or Pb; SiR3 = SiMe3, SiPh2Me or SiPh3), [{(iPrAr)(SiMe3)N}ECl] (E = Ge or Sn) and {(tBuAr)(SiMe3)N}GeCl. The structures of these complexes have been determined using X-ray crystallography. Furthermore, amido silicon(IV) halide complexes, [LSiX3] (SiR3 = SiMe3, SiPh2Me or SiPh3; X = Cl or Br) and [{(iPrAr)(SiR3)N}SiBr3], as well as an amido silicon hydride, [LSi(H)Cl2] have been synthesized and structurally investigated. Chapter 3 discusses the synthesis and structural characterization of the first singly-bonded amido-digermyne, [LGeGeL], and its reactivity towards small gas molecule activation, e.g. that of H2, CO2, N2O, etc. at ambient and low temperatures. These reactions produced bulky amido germanium(II) and germanium(III) hydride complexes, and a bis(germylene) oxide complex. Further efforts have been devoted to the reactivity of [LGeGeL] towards molecules such as CS2, tBuNC and tBuNCO. Chapter 4 expands on the reactivity of [LGeGeL] and [L#GeGeL#] (L# = (iPrAr)(SiiPr3)N). It describes reactions that have been carried out with organic molecules, e.g. cyclooctatetraene (COT), 4-dimethylaminopyridine (DMAP), azobenzene, 1,4-bis(trimethylsilyl)butadiyne, norbornadiene, etc. These reactions produced a number of low oxidation state germanium complexes. In general, the reactions of [LGeGeL] and [L#GeGeL#] with unsaturated molecules produced products with the substrate inserted into the Ge-Ge bond. However, the reaction with DMAP produced a bis-adducted germanium complex with a shortened Ge-Ge bond. Finally, reactions of [LGeGeL] with chlorinated compounds, iodine, and ketones are discussed. Chapter 5 summarizes investigations into the synthesis and coordination chemistry of the first examples of bulky amido "one-coordinate" germanium(II) and tin(II) monocationic complexes, [LE]+[PF]- (E = Ge or Sn, PF = [Al{OC(CF3)3}4]-) and [L'Sn]+[PF]- (L' = [(MeAr)(SiPh2Me)N]). Their reactivity towards DMAP was investigated, and this led to two-coordinate adducted germanium or tin cationic complexes. Chapter 6 summarizes miscellaneous results, and consists of two sections. The first section discusses theoretical investigations into the Mo-Ge bonding of singly-bonded or triply-bonded molybdenum germylene and germylyne complexes. Wiberg bond indices (WBI) were acquired to provide a quantitative description of the bonding in these complexes. The second section focuses on investigations into the synthesis of a bulky gallium(I) amide complex, [LGa:], which was prepared from the reaction of [{(MeAr)(SiMe3)N}Li] and "GaI". X-ray crystallographic studies of [LGa:] were carried out and indicate that the complex is essentially one-coordinate.

On the Catalytic Efficacy of Low-Oxidation State Group 14 Complexes

On the Catalytic Efficacy of Low-Oxidation State Group 14 Complexes
Author: Terrance John Hadlington
Publisher: Springer
Total Pages: 256
Release: 2017-02-14
Genre: Science
ISBN: 3319518070

This outstanding thesis describes a detailed investigation into the use of low-oxidation-state group 14 complexes in catalysis, developed at the cutting edge of inorganic and organometallic chemistry. It includes the preparation of a number of landmark compounds, some of which challenge our current understanding of metal–metal bonding and low-oxidation-state main group chemistry. Among the many highlights of this thesis, the standout result is the development of the first well-defined, low- oxidation-state main group hydride systems as highly efficient catalysts in the hydroboration of carbonyl substrates, including carbon dioxide, which are as efficient as those observed in more traditional, transition-metal catalyses. These results essentially define a new subdiscipline of chemistry.

Reactivity of Low-Valent Group 14 Species Toward Main Group Element, Transition Metal and Lanthanide Compounds

Reactivity of Low-Valent Group 14 Species Toward Main Group Element, Transition Metal and Lanthanide Compounds
Author: Xiaofei Sun
Publisher: Cuvillier Verlag
Total Pages: 259
Release: 2022-08-22
Genre: Science
ISBN: 3736966628

Die Dissertation befasst sich mit der Anwendung von niedervalenten Gruppe-14-Verbindungen in metallorganischer Chemie und Hauptgruppenchemie. Ausgehend von mono- und divalenten Siliziumverbindungen wurde die analoge Siliziumverbindung des 2π-Hückel-aromatischen Verbindung dargestellt (Kapitel 3.1). Ein chirales Silen wurde synthetisiert und weitere Reaktivität mit unterschiedlichen kleinen Molekülen untersucht (Kapitel 3.2). Außerdem wurden bidentate Silylene als Liganden zur Stabilisierung von Seldenerdelementen, Erdalkalielementen und Gruppe-12-Metallen eingesetzt (Kapitel 3.3-3.4). Verschiedene Polyphosphide wurden aus reduzierenden Silylenen oder Plumbolen generiert (Kapitel 3.5-3.6). Die dianionischen Gruppe-14-Metallole, Silol, Germol und Plumbol wurden als Liganden für sandwichartige Lanthanidkomplexe eingesetzt und die magnetischen Eigenschaften der Er-Verbindung wurden untersucht (Kapitel 3.7-3.8).

Studies of Low Oxidation State Group 13 and 14 Metallacycles

Studies of Low Oxidation State Group 13 and 14 Metallacycles
Author: William Douglas Woodul
Publisher:
Total Pages: 454
Release: 2011
Genre:
ISBN:

This thesis is mainly concerned with investigations into the reactivity of the gallium(I) N-heterocyclic carbene (NHC) analogue, [K(tmeda)][:Ga{[N(Dip)C(H)]2}] (Dip = C6H3Pri2-2,6). The preparation of the first monomeric Ge(I) radical was also investigated. Work carried out in these areas is divided into five chapters. Chapter 1 provides a general introduction to sub-valent group 13 and 14 chemistry, with an emphasis on the preparation of group 13 metal(I) and group 14 metal(II) N-heterocyclic carbene analogues. Chapter 2 summarizes investigations into the reactivity of [K(tmeda)] [:Ga{[N(Dip)C(H)]2}] towards groups 2 and 12 metal precursors. Reactions of magnesium, calcium, strontium, barium, zinc, and cadmium halides with [K(tmeda)][:Ga{[N(Dip)C(H)]2}] are discussed, and the first structurally characterized cadmium-gallium bonded molecular complex is reported. Chapter 3 summarizes investigations into the reactivity of [K(tmeda)] [:Ga{[N(Dip)C(H)]2}] towards selected lanthanide metal precursors. Reactions of samarium(II), europium(II), ytterbium(II), thulium(II), and cerium(III) iodides with [K(tmeda)][:Ga{[N(Dip)C(H)]2}] have given rise to a number of novel lanthanide-gallyl species, including the first structurally characterized GaTm or GaSm bonded complexes. Chapter 4 details the preparation of the first monomeric Ge(I) radical via the reduction of a bulky [beta]-diketiminato germanium(II) precursor. The verification of the +1 oxidation state in this species was achieved using a combination of crystallographic, EPR and ENDOR spectroscopic, and theoretical analyses. Chapter 5 describes several miscellaneous results, largely derived from attempts to prepare bulky guanidinato complexes of p-block elements in low oxidation states.

Inorganic Chemistry in Germany

Inorganic Chemistry in Germany
Author:
Publisher: Elsevier
Total Pages: 324
Release: 2023-09-29
Genre: Science
ISBN: 0443159459

Inorganic Chemistry in Germany, Volume 82 in the Advances in Inorganic Chemistry series, highlights advances in the field, with this new volume presenting chapters written by an international board of authors. Specific chapters focus on Cooperative effects in bimetallic and multimetallic complexes, Harnessing transition metal nitrido complexes for challenging bond activation reactions and catalysis, Applications of N-heterocyclic carbene-pnictogen compounds in transition metal chemistry and homogeneous catalysis, Aminopyridinato ligands – from quintuple bonding via hydrogen storage to selective olefin syntheses, Multifunctional Perspectives of Metal-Organic Frameworks, Recent advances in low valent silicon chemistry, Recent developments in CO2 reduction by aluminum and silicon compounds, and much more. Provides the authority and expertise of leading contributors from an international board of authors Presents the latest release in Advances in Inorganic Chemistry series Updated release includes the latest information on Inorganic Chemistry in Germany

Frustrated Lewis Pairs II

Frustrated Lewis Pairs II
Author: Gerhard Erker
Publisher: Springer
Total Pages: 321
Release: 2013-12-12
Genre: Science
ISBN: 3642377599

Frustrated Lewis Pairs: From Dihydrogen Activation to Asymmetric Catalysis, by Dianjun Chen, Jürgen Klankermayer Coexistence of Lewis Acid and Base Functions: A Generalized View of the Frustrated Lewis Pair Concept with Novel Implications for Reactivity, by Heinz Berke, Yanfeng Jiang, Xianghua Yang, Chunfang Jiang, Subrata Chakraborty, Anne Landwehr New Organoboranes in "Frustrated Lewis Pair" Chemistry, by Zhenpin Lu, Hongyan Ye, Huadong Wang Paracyclophane Derivatives in Frustrated Lewis Pair Chemistry, by Lutz Greb, Jan Paradies Novel Al-Based FLP Systems, by Werner Uhl, Ernst-Ulrich Würthwein N-Heterocyclic Carbenes in FLP Chemistry, by Eugene L. Kolychev, Eileen Theuergarten, Matthias Tamm Carbon-Based Frustrated Lewis Pairs, by Shabana Khan, Manuel Alcarazo Selective C-H Activations Using Frustrated Lewis Pairs. Applications in Organic Synthesis, by Paul Knochel, Konstantin Karaghiosoff, Sophia Manolikakes FLP-Mediated Activations and Reductions of CO2 and CO, by Andrew E. Ashley, Dermot O’Hare Radical Frustrated Lewis Pairs, by Timothy H. Warren and Gerhard Erker Polymerization by Classical and Frustrated Lewis Pairs, by Eugene Y.-X. Chen Frustrated Lewis Pairs Beyond the Main Group: Transition Metal-Containing Systems, by D. Wass Reactions of Phosphine-Boranes and Related Frustrated Lewis Pairs with Transition Metal Complexes, by Abderrahmane Amgoune, Ghenwa Bouhadir, Didier Bourissou

The Synthesis and Stabilisation of Low Oxidation State Complexes: Utilising Magnesium(I) Dimers as Reducing Agents

The Synthesis and Stabilisation of Low Oxidation State Complexes: Utilising Magnesium(I) Dimers as Reducing Agents
Author: Simon James Bonyhady
Publisher:
Total Pages: 594
Release: 2013
Genre:
ISBN:

This thesis pertains to the synthesis and stabilisation of low oxidation state main group element complexes through the utilisation of novel magnesium(I) dimers as reducing agents. As such, it is an exploration of the utility of these magnesium(I) complexes in organometallic synthesis and has resulted in the isolation of a number of compounds featuring unusual structural motifs, oxidation states and bonding modes.Chapter 1 provides a general introduction to low oxidation state main group chemistry and discusses a number of concepts that are unique to this field of study. Particular attention is paid to historical concepts such as the "double bond rule" and the new understanding of chemical bonding that has developed as a result of this "renaissance" in main group chemistry, as well as a general discussion of synthetic methods to access these compounds.Chapter 2 introduces the magnesium(I) dimers reported to date and details both their synthesis and reactivity in organic and organometallic synthesis. Two new [beta]-diketiminato magnesium(I) complexes are described, along with their [beta]-diketiminato magnesium(II) halide precursor complexes, and efforts towards improving the synthesis of these unusual compounds are outlined. A number of other novel [beta]-diketiminato magnesium(II) hydride, alkyl and halide complexes are also presented. Finally, efforts towards the synthesis of soluble models of magnesium amido-boranes, in which this library of magnesium(I and II) complexes is exploited, are also discussed.Chapter 3 presents a case study into the utility of magnesium(I) dimers as reducing agents in organometallic synthesis. A series of amidinato group 14 element(I) dimers [LEEL] (E = Si, Ge, Sn; L = amidinate) were synthesised in high to moderate yield, and comparisons between the magnesium(I) dimers and traditional reducing agents emphasised the efficacy of the magnesium(I) dimers in this role. The tin compound is the first of its type, while one and two previous examples exist for the silicon and germanium complexes, respectively, although they were only isolated in low yield.Chapter 4 describes the development of low oxidation state aluminium hydride chemistry, an area in which magnesium(I) dimers have been instrumental. A number of novel compounds are presented including of a series of compounds which feature remarkable [Al6H6] octahedral cores.Chapter 5 details efforts to extend the use of magnesium(I) dimers to compounds stabilised by bulky terphenyl ligands. The preparation of the second example of a diplumbyne, for which a moderate yielding synthesis was determined, is described. A dialumene and a disilyne were also desirable synthetic targets, and efforts to these ends are also outlined.Finally, Chapter 6 provides a summary of the results presented in this thesis.

Preparation, Characterisation and Reactivity of Low Oxidation State d-Block Metal Complexes Stabilised by Extremely Bulky Amide Ligands

Preparation, Characterisation and Reactivity of Low Oxidation State d-Block Metal Complexes Stabilised by Extremely Bulky Amide Ligands
Author: Jamie Hicks
Publisher: Springer
Total Pages: 214
Release: 2016-10-24
Genre: Science
ISBN: 9811029059

This thesis describes the synthesis and characterization of numerous metal-metal bonded complexes that are stabilized by extremely bulky amide ligands. It provides a comprehensive overview of the field, including discussions on groundbreaking complexes and reactions, before presenting in detail, exciting new findings from the PhD studies. The thesis appeals to researchers, professors and chemistry undergraduates with an interest in inorganic and/or organometallic chemistry.

Organometallic Compounds of Low-Coordinate Si, Ge, Sn and Pb

Organometallic Compounds of Low-Coordinate Si, Ge, Sn and Pb
Author: Vladimir Ya. Lee
Publisher: John Wiley & Sons
Total Pages: 390
Release: 2011-07-22
Genre: Science
ISBN: 1119956269

Until recently the low-coordinate compounds of the heavier elements of group 14 were known only as transient, unstable species which were difficult to isolate. However recent developments have led to the stabilisation of these compounds and today heavier group 14 element cations, radicals, anions, carbene analogues, alkene and alkyne analogues and aromatics have all been prepared as highly reactive, stable, fully characterizable and readily available organometallic reagents. Organometallic Compounds of Low-Coordinate Si, Ge, Sn and Pb describes the chemistry of this exciting new class of organometallics, with an emphasis on their major similarities and differences with the analogous species in organic chemistry. Topics covered include include the synthesis, structure, reactions and synthetic applications of : Si-, Ge-, Sn and Pb-centered cations, radicals and anions heavy analogues of carbenes: silylenes, germylenes, stannylenes and plumbylenes heavy analogues of alkenes: disilenes, digermenes, distannenes, diplumbenes heavy analogues of alkynes: disilynes, digermynes, distannynes, diplumbynes, and their valence isomers heteronuclear derivatives: silenes, germenes, stannenes, silagermenes, silastannenes, germastannenes heavy analogues of alkenes of the type: >E14=E13-, >E14=E15-, >E14=E16 [where E13, E14, E15 and E16 are elements of the groups 13, 14, 15 and 16] cyclic compounds (three-, four-, five-, and six-membered rings) heavy analogues of 1,3-dienes, allenes and other cumulenes heavy analogues of aromatic compounds; including a comparison between organometallic and organic aromaticity Organometallic Compounds of Low-Coordinate Si, Ge, Sn and Pb is an essential guide to this emerging class of organometallic reagents for researchers and students in main group, organometallic, synthetic and silicon chemistry