Abstract Transition metal complexes with multidentate phosphorous/nitrogen ligands. Synthesis, characterization and reactivity. By Sergio Santiago Rozenel Doctor in Philosophy in Chemistry University of California, Berkeley Professor John Arnold, Chair Chapter 1: Chromium complexes supported by the multidentate monoanionic ligand [N2P2] {H[N2P2] = tBuN(H)SiMe2N(CH2CH2PiPr2)2} are presented, and the activity of these complexes towards ethylene oligomerization/polymerization is examined. The complexes [N2P2]CrCl2 (1) and [N2P2]CrCl (2) polymerized ethylene after activation with MAO. Derivatives of 1 and 2 were synthesized in order to gain insights about the active species in the ethylene oligomerization/polymerization processes. The alkyl complexes [N2P2]CrMe (3), [N2P2]CrCH2SiMe3 (4) and [N2P2]Cr(Cl)CH2SiMe3 (5), the cationic species {[N2P2]CrCl}BF4 (7), {[N2P2]CrCl}BPh4 (8) and {[N2P2]CrCH2SiMe3}BF4 (9), and the Cr(II) complex [N2P2]CrOSO2CF3 (11) were not active ethylene oligomerization/polymerization catalysts in absence of an activator. Reaction of 1 with two equivalents of MeLi led to reduction to 3. However, with one equivalent of MeLi the stable mixed alkyl-halide derivative [N2P2]Cr(Cl)Me (6) was obtained. Reaction of 2 with Red-Al® produced the hydride ([N2P2]Cr)2(ì-H)2 (10), which reacted with CO to produce the Cr(I) complex [N2P2]Cr(CO)2 (12). Reduction of 2 with KC8 in the presence of p-tolyl azide produced the dimeric cis μ-imido ([N2P2]Cr)2(ì-NC7H7)2 (13). A similar reduction in the presence of ethylene resulted in the isolation of the Cr(III) metallacyclohexane compound [N2P2]CrC4H8 (14). Chapter 2: A series of Co, Ni and Cu complexes with the ligand HN(CH2CH2PiPr2)2 (HPNP) has been isolated and their electrochemical behavior investigated by cyclic voltammetry. The nickel complexes [(HPNP¬)NiOTf]OTf and [(HPNP)NiNCCH3](BF4)2 display reversible reductions, as does the related amide derivative (NP2)NiBr. Related copper(I) and cobalt(II) derivatives were isolated and characterized. Addition of piperidine to [(HNP2)NiNCCH3](BF4)2 led to the formation of the new species [(HPNP)Ni(N(H)C(CH3)NC5H10)](BF4)2. Nucleophilic addition of piperidine to acetonitrile to produce HN=C(CH3)NC5H10 was catalyzed by [(HPNP)NiNCCH3](BF4)2. Chapter 3: A series of bimetallic ruthenium complexes [HPNPRu(N2)]2(μ-Cl)2](BF4)2 (2), [(HPNPRu(H2)Cl)2(μ-Cl)2](BF4)2 (3), [(HPNPRu)2(μ-H2NNH2)(μ-Cl)2](BF4)2 (4), [(HPNPRu)2(μ-Cl)2(μ-HNNPh)](BF4)2 (5), [HPNPRu(NH3)(ç2-N2H4)](BF4)Cl (6), [(HNP2Ru)2(μ-Cl)2(μ2-OSO2CF3)]OSO2CF3 (7), [HPNPRu]2(μ-Cl)3]BPh4 (8) and [HPNPRu]2(μ-Cl)3]BF4 (9) were isolated and characterized in the course of reactions aimed at studying the reduction of N2 and hydrazine. Complex 4 produces ammonia catalytically from hydrazine, and complex 2 generates ammonia upon reaction with Cp2Co/HLuBF4. DFT calculations support the idea that the diazene complex formed is more stable than the expected Chatt-type intermediate. Chapter 4: The reduction chemistry of cobalt complexes with the PNP ligand was explored. Reaction of (HPNP)CoCl2 (1) with n-BuLi generated the deprotonated Co(II) product (PNP)CoCl (2), and the Co(I) reduced species (HPNP)CoCl (3). The reaction of complex 2 with KC8 was investigated, where it was found that the products obtained depended upon the inert gas used to carry out the reaction: (PNP)CoN2 (4) under N2, bimetallic complex [(PNP)Co]2 (5) under Ar, and (HPNP)Co(H)3 (8) under H2. Complex 5 reacted with H2 to generate the bimetallic complex [(PNP)CoH]2 (6). With H2, H3SiPh and AgBPh4 complex 3 generated the species (HPNP)CoCl(H)2 (9), (HPNP)CoCl(H)SiH2Ph (10) and [(HPNP)CoCl]BPh4 (11) respectively. DFT calculations were performed to gain insights about the transformations observed.

This book explores synthesis, structural changes, properties, and potential applications of transition metal (TM) compounds. Over three sections, chapters cover such topics as the synthesis of pentoxide vanadium (V2O5), the effect of TM compounds on structural, dielectric properties and high-temperature superconductors, and TM-doped nanocrystals (NCs).

Direct Synthesis of Metal Complexes provides in-depth coverage of the direct synthesis of coordination and organometallic compounds. The work is primarily organized by methods, but also covers highly relevant complexes, such as metal-polymer coordination compounds. This updated reference discusses recent developments in cryosynthesis, electrosynthesis, and tribosynthesis (popular as it doesn't require organic solvents), with special attention paid to 'greener' methodologies and approaches. Additionally, the book describes physical methods of zero-valent metal interaction with organic matter, including sputtering, ultrasonic treatment and synthesis in ionic liquids. The book presents completely new content as a follow-up to the 1999 Elsevier Science publication Direct Synthesis of Coordination and Organometallic Compounds that was edited by Dr. Garnovskii and Dr. Kharisov. - Covers current methods and techniques of metal interactions with organic media leading to metal chelates, adducts, di- and polymetallic complexes, metal-containing macrocycles, supported coordination compounds (i.e., metal complexes on carbon nanotubes), and more - Describes reactivities of distinct forms of elemental metals (powders, sheets, nanoparticles (including a host of less-common metal nanostructures) with organic phase (liquid, solid and gaseous) and water - Includes experimental procedures, with examples of direct synthesis, at the end of each chapter