Tristram Chivers

Bio: Tristram Chivers is an academic researcher from University of Calgary. The author has contributed to research in topics: Ring (chemistry) & Crystal structure. The author has an hindex of 42, co-authored 546 publications receiving 8594 citations. Previous affiliations of Tristram Chivers include University of Bristol & University of St Andrews.

Pentafluorophenylboranes: from obscurity to applications

Abstract: Pentafluorophenyl substituted boranes and borates are important as co-catalysts in metallocene-based industrial processes for the homogeneous polymerization of olefins. Although first prepared in the early 1960s, the remarkable properties of tris(pentafluorophenyl)borane have only recently been exploited for applications in catalysis. Spurred by these developments, the related compounds bis(pentafluorophenyl)borane and salts of the tetrakis(pentafluorophenyl)borate anion have also found application in olefin polymerization and other fields. In this article, we trace the rise of pentafluorophenyl boron compounds from curiosities to important commodities.

Tellurium: a maverick among the chalcogens

Abstract: The scant attention paid to tellurium in both inorganic and organic chemistry textbooks may reflect, in part, the very low natural abundance of the element. Such treatments commonly imply that the structures and reactivities of tellurium compounds can be extrapolated from the behaviour of their lighter chalcogen analogues (sulfur and selenium). In fact, recent findings and well-established observations clearly illustrate that this assumption is not valid. The emerging importance of the unique properties of tellurium compounds is apparent from the variety of their known and potential applications in both inorganic and organic chemistry, as well as materials science. With reference to selected contemporary examples, this Tutorial Review examines the fundamental concepts that are essential for an understanding of the unique features of tellurium chemistry with an emphasis on hypervalency, three-centre bonding, secondary bonding interactions, σ and π-bond energies (multiply bonded compounds), and Lewis acid behaviour.

The role of polysulfide dianions and radical anions in the chemical, physical and biological sciences, including sulfur-based batteries

Abstract: Correction for ‘The role of polysulfide dianions and radical anions in the chemical, physical and biological sciences, including sulfur-based batteries’ by Ralf Steudel et al., Chem. Soc. Rev., 2019, 48, 3279–3319.

A new route to antimony telluride nanoplates from a single-source precursor.

Abstract: Aerosol-assisted chemical vapor deposition (AACVD) of Sb[(TePiPr2)2N]3 results in pure hexagonal Sb2Te3 nanoplates between 375 and 475 °C on glass substrates, with a potential for enhanced thermoelectric properties for novel nanodevices.

Ubiquitous trisulfur radical anion: fundamentals and applications in materials science, electrochemistry, analytical chemistry and geochemistry.

Abstract: The trisulfur radical anion [S3]˙− is well-known from inorganic chemistry textbooks as the blue chromophore in ultramarine blues in which this highly reactive species is trapped in a zeolitic framework. Recent findings have revealed that [S3]˙− has a multi-faceted role in a variety of media, including alkali metal–sulfur batteries, aqueous solutions at high temperatures and pressures, and ionic liquids; it has also been used to detect trace amounts of water in organic solvents. This tutorial review illustrates how various physical techniques are used to identify a reactive species in solution and shows how elucidation of electronic structures can be used to explain spectroscopic and structural properties. Examples of the function of [S3]˙− in materials science, electrochemistry, analytical chemistry and geochemistry are used to illustrate the widespread influence of this fundamentally important triatomic sulfur species.

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

Gadolinium(III) Chelates as MRI Contrast Agents: Structure, Dynamics, and Applications

Abstract: A. Water Exchange 2326 B. Proton Exchange 2327 C. Electronic Relaxation 2327 D. Relaxivity 2331 E. Outerand Second-Sphere Relaxivity 2334 F. Methods of Improving Relaxivity 2336 V. Macromolecular Conjugates 2336 A. Introduction 2336 B. General Conjugation Methods 2336 C. Synthetic Linear Polymers 2336 D. Synthetic Dendrimer-Based Agents 2338 E. Naturally Occurring Polymers (Proteins, Polysaccharides, and Nucleic Acids) 2339

Ab initio calculation of vibrational absorption and circular dichroism spectra using density functional force fields

Abstract: : The unpolarized absorption and circular dichroism spectra of the fundamental vibrational transitions of the chiral molecule, 4-methyl-2-oxetanone, are calculated ab initio. Harmonic force fields are obtained using Density Functional Theory (DFT), MP2, and SCF methodologies and a 5S4P2D/3S2P (TZ2P) basis set. DFT calculations use the Local Spin Density Approximation (LSDA), BLYP, and Becke3LYP (B3LYP) density functionals. Mid-IR spectra predicted using LSDA, BLYP, and B3LYP force fields are of significantly different quality, the B3LYP force field yielding spectra in clearly superior, and overall excellent, agreement with experiment. The MP2 force field yields spectra in slightly worse agreement with experiment than the B3LYP force field. The SCF force field yields spectra in poor agreement with experiment.The basis set dependence of B3LYP force fields is also explored: the 6-31G* and TZ2P basis sets give very similar results while the 3-21G basis set yields spectra in substantially worse agreements with experiment. jg