Structural chemistry of metal coordination complexes at high pressure

The application of pressures of up to about 10 GPa may induce significant geometric, configurational, conformational and packing changes in molecular solids. This review highlights and describes recent advances in high pressure studies of coordination complexes, many of which have been conducted at synchrotrons or other central facilities. The main focus is on the wide range of geometric changes which occur with pressure. In some cases these changes have associated physical effects, and the review describes materials exhibiting negative linear compressibility, spin cross-over phenomena, magnetism and molecular conduction, as well as detailing the exciting possibilities for future developments in this area of research

Self-assembly in polyoxometalate and metal coordination-based systems: synthetic approaches and developments

Utilizing new experimental approaches and gradual understanding of the underlying chemical processes has led to advances in the self-assembly of inorganic and metal–organic compounds at a very fast pace over the last decades. Exploitation of unveiled information originating from initial experimental observations has sparked the development of new families of compounds with unique structural characteristics and functionalities. The main source of inspiration for numerous research groups originated from the implementation of the design element along with the discovery of new chemical components which can self-assemble into complex structures with wide range of sizes, topologies and functionalities. Not only do self-assembled inorganic and metal–organic chemical systems belong to families of compounds with configurable structures, but also have a vast array of physical properties which reflect the chemical information stored in the various “modular” molecular subunits. The purpose of this short review article is not the exhaustive discussion of the broad field of inorganic and metal–organic chemical systems, but the discussion of some representative examples from each category which demonstrate the implementation of new synthetic approaches and design principles

Development of covalent triazine frameworks as heterogeneous catalytic supports

Covalent triazine frameworks (CTFs) are established as an emerging class of porous organic polymers with remarkable features such as large surface area and permanent porosity, high thermal and chemical stability, and convenient functionalization that promotes great potential in heterogeneous catalysis. In this article, we systematically present the structural design of CTFs as a versatile scaffold to develop heterogeneous catalysts for a variety of chemical reactions. We mainly focus on the functionalization of CTFs, including their use for incorporating and stabilization of nanoparticles and immobilization of molecular complexes onto the frameworks

The synthesis and characterization of new higher nuclearity arene-ruthenium-sulfur clusters : a thesis presented in partial fulfillment of the requirements for the degree of Master of Science in Chemistry at Massey University, New Zealand

This thesis describes a project investigating the synthesis and characterization of new higher nuclearity arene-ruthenium-sulfur clusters and arene-ruthenium-nitrogen complexes. The thesis is divided into four chapters, with the introduction in Chapter One. The synthesis and characterization of new higher nuclearity arene-ruthenium-sulfur clusters are described in Chapter Two. These include two novel clusters, [Ru₅S₄(cymene)₄](PF₆)₂, [Ru₄(S₂)(SO)(cymene)₄](PF₆)₂ and one known cluster, [Ru₃S₂(cymene)₃](PF₆)₂. The X-ray crystallographic structures of these three arene-ruthenium-sulfur clusters are discussed in detail including how the number of valence electrons influences the structure, how the solid state structure and single crystal structure effect each other and how the structures determine the chemical shifts and other characters of the clusters. The unusual signals of these three clusters on ¹H NMR spectra are discussed carefully. The mechanisms of formation of arene-ruthenium-sulfur clusters are described in detail. Some electrochemistry and calculations (quantum chemistry) are also involved. The synthesis and characterization of arene-ruthenium-nitrogen complexes are described in Chapter Three. These include two new mono-nuclear complexes, [RuCl₂(NH₃)(cymene)], [Ru(NH₃)₃(cymene)](PF₆)₂, one novel amide dimer [RuCl(NH₂)(cymene)]₂ and one known complex, [RuCl(NH₃)₂(cymene)]PF₆. The mechanisms of reactions in which they are formed are also discussed. In Chapter Four, the experimental data is presented. The X ray crystallography of [Ru₅S₄(cymene)₄](PF₆)₂, [Ru₄(S₂)(SO)(cymene)₄](PF₆)₂, [RuCl₂(NH₃)(cymene)] and [RuCl(NH₂)(cymene)]₂ is described in detail

Coordination chemistry of amide-functionalised tetraazamacrocycles: structural, relaxometric and cytotoxicity studies

Three different tetraazamacrocyclic ligands containing four amide substituents that feature groups (namely allyl, styryl and propargyl groups) suitable for polymerisation have been synthesised. Gadolinium(III) complexes of these three ligands have been prepared as potential monomers for the synthesis of polymeric MRI contrast agents. To assess the potential of these monomers as MRI contrast agents, their relaxation enhancement properties and cytotoxicity have been determined. A europium(III) complex of one of these ligands (with propargyl substituents) is also presented together with its PARACEST properties. In addition, to gain further insight into the coordination chemistry of the tetra-propargyl substituted ligand, the corresponding zinc(II) and cadmium(II) complexes have been prepared. The X-ray crystal structures of the tetra-propargyl ligand and its corresponding gadolinium(III), zinc(II) and cadmium(II) complexes are also presented

Bioinorganic Chemistry

This book covers material that could be included in a one-quarter or one-semester course in bioinorganic chemistry for graduate students and advanced undergraduate students in chemistry or biochemistry. We believe that such a course should provide students with the background required to follow the research literature in the field. The topics were chosen to represent those areas of bioinorganic chemistry that are mature enough for textbook presentation. Although each chapter presents material at a more advanced level than that of bioinorganic textbooks published previously, the chapters are not specialized review articles. What we have attempted to do in each chapter is to teach the underlying principles of bioinorganic chemistry as well as outlining the state of knowledge in selected areas. We have chosen not to include abbreviated summaries of the inorganic chemistry, biochemistry, and spectroscopy that students may need as background in order to master the material presented. We instead assume that the instructor using this book will assign reading from relevant sources that is appropriate to the background of the students taking the course. For the convenience of the instructors, students, and other readers of this book, we have included an appendix that lists references to reviews of the research literature that we have found to be particularly useful in our courses on bioinorganic chemistry

Organometallic fragments in microporous solids: intrazeolite chemistry of (cyclooctatetraene)iron tricarbonyl

The intrazeolite reactivity of (COT)Fe(CO)3 (COT = cyclooctatetraene) [ 11 in faujasites having different levels of Bronsted acidity was examined with extended X-ray absorption fine structure, vibrational, and temperature programmed desorption/mass spectrometric techniques. The data show that the precursor complex [l] associates with Na-Y zeolite, resulting in symmetry changes of the Fe(C0)3 fragment while 1 remains chemically intact. If (COT)Fe(CO)3 is adsorbed into highly acidic H-Y zeolite at room temperature, bicyclo[5.1 .O]octadienyliron tricarbonyl cation is formed in a clean reaction. This reaction corresponds to the protonation of 1 with noncoordinating acids in homogeneous solution. At elevated temperatures, the carbonyl ligands are cleaved off and the remaining organo-iron fragment is anchored to framework oxygens of the large zeolite supercages

Nitrosyl-heme and anion-arene complexes: structure, reactivity and spectroscopy

Two topics are selected and illustrated to exemplify (i) a biological and (ii) an organic ionic intermediate. The reactivity behavior of NO adducts with ferric and ferrous hemes has shown remarkable similarities when examined in the gas phase, demonstrating that the largely different NO affinity displayed in solution and in biological media is due to the different coordination environment. In fact, ferrous hemes present a vacant or highly labile axial coordination site, prone to readily bind NO. The vibrational signatures of the NO ligand have also been probed in vacuo for the first time in the nitrosyl complexes deriving from ferrous and ferric hemes under strictly comparable five-coordination at the metal center. Negatively charged sigma-adducts, from the association of anions with 1,3,5-trinitrobenzene, an exemplary pi-electron-deficient arene, have been probed by IRMPD spectroscopy and found to display variable binding motifs from a strongly covalent sigma-adduct (Meisenheimer complex) to a weakly covalent sigma-complex, depending on the anion basicity

A Second-Generation Janus Scorpionate Ligand: Controlling Coordination Modes in Iron(II) Complexes by Steric Modulation

The second-generation Janus scorpionate ligand [HB(mtdaMe)3−] containing methyl-mercaptothiadiazolyl (mtdaMe) heterocyclic rings and (N,N,N-) and (S,S,S-) binding pockets has been prepared. The effect of methyl substitution versus the unsubstituted first-generation Janus scorpionate [HB(mtda)3]− on the coordination chemistry with alkali metals and on the binding preferences and on the ground spin state of iron(II) complexes has been studied structurally and by 57Fe Mossbauer Spectroscopy