Inorganic Coordination Chemistry Research Articles

A homologous series of structures on the surface of SrTiO3(110)

Strontium titanate is seeing increasing interest in fields ranging from thin-film growth to water-splitting catalysis and electronic devices. Although the surface structure and chemistry are of vital importance to many of these applications, theories about the driving forces vary widely. We report here a solution to the 3 x 1 SrTiO(3)(110) surface structure obtained through transmission electron diffraction and direct methods, and confirmed through density functional theory calculations and scanning tunnelling microscopy images and simulations, consisting of rings of six or eight corner-sharing TiO(4) tetrahedra. Further, by changing the number of tetrahedra per ring, a homologous series of n x 1 (n > or = 2) surface reconstructions is formed. Calculations show that the lower members of the series (n < or = 6) are thermodynamically stable and the structures agree with scanning tunnelling microscopy images. Although the surface energy of a crystal is usually thought to determine the structure and stoichiometry, we demonstrate that the opposite can occur. The n x 1 reconstructions are sufficiently close in energy for the stoichiometry in the near-surface region to determine which reconstruction is formed. Our results indicate that the rules of inorganic coordination chemistry apply to oxide surfaces, with concepts such as homologous series and intergrowths as valid at the surface as they are in the bulk.

Aminoethylglycine-Functionalized Ru(bpy)32+ with Pendant Bipyridines Self-Assemble Multimetallic Complexes by Copper and Zinc Coordination

Directed self-assembly using inorganic coordination chemistry is an attractive approach for making functional supramolecular structures. In this article, the synthesis and characterization of Ru(bpy) 3 (2+) compounds derivatized with aminoethylglycine (aeg) substituents containing pendant bipyridine (bpy) ligands is presented. The free bpy ligands in these complexes are available for metal chelation to form coordinative cross-links; addition of Cu (2+) or Zn (2+) assembles heterometallic structures containing two or three transition-metal complexes. Control over relative placement of metal complexes is accomplished using two strategies: two bipyridine-containing aeg strands tethered to Ru(bpy) 3 (2+) allow intramolecular coordination and result in a dimetallic hairpin motif. Ru(bpy) 3 (2+) modified with a single strand forms intermolecular cross-links forming the trimetallic complex. Each of these is characterized by a range of methods, and their photophysical properties are compared. These data, and comparison to an acetyl aeg- modified Ru(bpy) 3 (2+) complex, confirm that the metal ions cross-link bpy-containing aeg strands. Heterometallic complexes containing bound Cu (2+) cause a dramatic reduction in the Ru(bpy) 3 (2+) quantum yields and lifetimes. In contrast, the Ru(bpy) 3 (2+) hairpin with coordinated Zn (2+) has only a slight decrease in quantum yield but no change in lifetime, which could be a result of steric impacts on structure in the dimetallic species. Analogous effects are not observed in the trimetallic Ru-Zn-Ru structures in which this constraint is absent. Each of these heterometallic structures represents a facile and reconfigurable means to construct multimetallic structures by metal-coordination-based self-assembly of modular artificial peptide units.

Éloge: Fred Basolo (1920–2007)

The life and career of Fred Basolo (1920–2007), dean of American coordination chemistry, 1983 President of the American Chemical Society, and contributor to inorganic chemistry, coordination chemistry, physical chemistry, and chemical education over a span of more than half a century, are discussed in this obituary-tribute.

WebWatch

BioTechniquesVol. 43, No. 3 WebWatchOpen AccessWebWatchKevin AhernKevin AhernSearch for more papers by this authorPublished Online:16 May 2018https://doi.org/10.2144/000112545AboutSectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinkedInRedditEmail Cellular Sorting SortedCellular organelles and complexes in which proteins are found span from A (axoneme) to V (vacuolar membrane), if the data in OrganelleDB is to be believed. To imply that the database housed therein is anything less than extensive, however, would not be accurate. With over 50 subcellular structures from over 130 species in its collection, the site is literally a one-stop shop for intracellular protein localization. Organized by Anuj Kumar at the University of Michigan, OrganelleDB emphasizes major model organisms in its coverage, including yeast, Arabidopsis, Drosophila, Caenorhabditis, mouse, and humans. Information is accessed via a “Quick” search engine on the opening page or an organelle-specific search system internal to the site. Spanning over 34,000 records from almost as many genes, OrganelleDB delivers data like the Energizer bunny provides power on and on…@ organelledb.Isi.umich.eduBrainy MattersPeruse the Comparative Mammalian Brain Collection and you'll probably be amazed at the anatomical similarity among mammalian brains. There are important differences, though. Compare, for example, the brain sizes of humans and our nearest relatives on the site's Paleoneurology and Brain Evolution pages. Except for a couple of vastly larger organisms (blue whales and elephants), we can feel smug that human brains are truly number one. The measure of a brain is not simply mass, but instead architecture, neural connections, and what the site calls “functional repertoires” that span almost all of vertebrate biology. Encompassing perception, locomotor abilities, instincts/reflexes, attention to environmental stimuli, learning, social interactions, and other behavioral characteristics, mammalian brains seem to have more in common than they do differences. If cranial contents constitute your interests, brainmuseum.org is a no-brainer.@ www.brainmuseum.orgArt and ScienceCells are the fundamental units of organisms, of course, so without an understanding of microbiology, one can't have a truly comprehensive perspective of life. It stands to reason, therefore, that a good microscope is an essential tool for modern biology, but what to look for in one? Ron Neumeyer, at his Microscope Forum page of the Microimaging site, addresses the question with detailed considerations of each component of a typical instrument. Not content with this or even with illustrated illumination techniques, Ron's pages also contain some of the most beautiful images of the visual micro-world to be found on the Web. Spanning the biological (protozoa, animals, and plants) and non-biological systems (sand and decorative images), Microimaging reposes the ancient question, “Does science imitate art or vice-versa?”@ microimaging.caGetting HyperAimed originally in 1994 at graduate students preparing for cumulative exams, the Organometallic HyperText Book (OHT) is a set of pages whose scope has expanded significantly in the 13 years of its existence. A labor-of-love for Rob Toreki, OHT is practically a course in organometallic chemistry all by itself. Defined as a “subset of inorganic coordination chemistry,” organometallic reactions create an interesting and diverse collection of molecules containing metal-carbon bonds. At OHT, visitors will find numerous opportunities to “learn by clicking” the chemical reactions, geometry, spectroscopy, and rules for predicting the reactivity of these interesting compounds.@ www.ilpi.com/organomet/index.htmlThe Last WordIn any listing of important molecular biology-related Web sites, Zlab is likely to get the last word, if only on an alphabetical basis. The site's organizers, who describe themselves as “a bunch of young people eager to establish careers in Bioinformatics and Biomolecular Engineering,” are, in fact, members of Dr. Zhiping Weng's lab at Boston University. With a primary purpose of providing tools useful for studying gene regulation and protein engineering, Zlab points users to powerful online resources for identifying promoters, over-represented motifs in DNA, transcription factor binding sites, protein domains, and much, much more.@ zlab.bu.edu/zlab/index.shtmlFiguresReferencesRelatedDetails Vol. 43, No. 3 Follow us on social media for the latest updates Metrics Downloaded 113 times History Published online 16 May 2018 Published in print September 2007 Information© 2007 Author(s)PDF download

N-Heterocyclic Carbenes: A New Concept in Organometallic Catalysis

N-Heterocyclic carbenes have become universal ligands in organometallic and inorganic coordination chemistry. They not only bind to any transition metal, be it in low or high oxidation states, but also to main group elements such as beryllium, sulfur, and iodine. Because of their specific coordination chemistry, N-heterocyclic carbenes both stabilize and activate metal centers in quite different key catalytic steps of organic syntheses, for example, C-H activation, C-C, C-H, C-O, and C-N bond formation. There is now ample evidence that in the new generation of organometallic catalysts the established ligand class of organophosphanes will be supplemented and, in part, replaced by N-heterocyclic carbenes. Over the past few years, this chemistry has been the field of vivid scientific competition, and yielded previously unexpected successes in key areas of homogeneous catalysis. From the work in numerous academic laboratories and in industry, a revolutionary turning point in oraganometallic catalysis is emerging.

Programming the assembly of two- and three-dimensional architectures with DNA and nanoscale inorganic building blocks.

The use of biochemical molecular recognition principles for the assembly of nanoscale inorganic building blocks into macroscopic functional materials constitutes a new frontier in science. This article details efforts pertaining to the use of sequence-specific DNA hybridization events and novel inorganic surface coordination chemistry to control the formation of both two- and three-dimensional functional architectures.

New Directions in Inorganic and Metal-Organic Coordination Chemistry in Supercritical Fluids.

New Directions in Inorganic and Metal-Organic Coordination Chemistry in Supercritical Fluids.

The chemistry of peroxovanadium compounds relevant to insulin mimesis.

The inorganic coordination chemistry of peroxovanadium compounds relevant to insulin mimesis is reviewed. The structure and kinetic reactivity of solutions of vanadate anion, vanadyl complexes and peroxovanadate complexes are briefly compared. Peroxovanadium compounds contain an oxo group, one or two peroxo ligands (O2(2-)) and an ancillary ligand which is usually bidentate. These compounds approximate a trigonal bipyramidal structure which can be divided conceptually into a polar 'oxo' half and a relatively non-polar organic half. This presents a number of interesting design variations which are discussed with respect to the development of a rudimentary structure-activity correlation of insulin mimetic ability.

SOME APPLICATIONS OF INFRARED SPECTROSCOPY TO INORGANIC CHEMISTRY

SUMMARY This paper is the text of a lecture given at the University of Cape Town to an audience comprising principally non-chemical scientists. It introduces the basic concepts of vibrational spectroscopy and describes the various band assignment techniques. Finally it shows how the technique of infrared spectroscopy may be employed to resolve some structural and bonding problems in inorganic co-ordination chemistry.