The halogen bond occurs when there is evidence of a net attractive interaction between an electrophilic region associated with a halogen atom in a molecular entity and a nucleophilic region in another, or the same, molecular entity. In this fairly extensive review, after a brief history of the interaction, we will provide the reader with a snapshot of where the research on the halogen bond is now, and, perhaps, where it is going. The specific advantages brought up by a design based on the use of the halogen bond will be demonstrated in quite different fields spanning from material sciences to biomolecular recognition and drug design.

The Halogen Bond

The design and implementation of cascade reactions is a challenging facet of organic chemistry, yet one that can impart striking novelty, elegance, and efficiency to synthetic strategies. The application of cascade reactions to natural products synthesis represents a particularly demanding task, but the results can be both stunning and instructive. This Review highlights selected examples of cascade reactions in total synthesis, with particular emphasis on recent applications therein. The examples discussed herein illustrate the power of these processes in the construction of complex molecules and underscore their future potential in chemical synthesis.

Cascade reactions in total synthesis.

Note: Times Cited: 875 Reference EPFL-ARTICLE-206025doi:10.1021/cr0501846View record in Web of Science URL: ://WOS:000249839900009 Record created on 2015-03-03, modified on 2017-05-12

Complex Hydrides for Hydrogen Storage

The platinum drugs, cisplatin, carboplatin, and oxaliplatin, prevail in the treatment of cancer, but new platinum agents have been very slow to enter the clinic. Recently, however, there has been a surge of activity, based on a great deal of mechanistic information, aimed at developing nonclassical platinum complexes that operate via mechanisms of action distinct from those of the approved drugs. The use of nanodelivery devices has also grown, and many different strategies have been explored to incorporate platinum warheads into nanomedicine constructs. In this Review, we discuss these efforts to create the next generation of platinum anticancer drugs. The introduction provides the reader with a brief overview of the use, development, and mechanism of action of the approved platinum drugs to provide the context in which more recent research has flourished. We then describe approaches that explore nonclassical platinum(II) complexes with trans geometry or with a monofunctional coordination mode, polynuclea...

The Next Generation of Platinum Drugs: Targeted Pt(II) Agents, Nanoparticle Delivery, and Pt(IV) Prodrugs

: 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

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

Monomeric titanium and zirconium complexes with multiple bonds to oxygen, sulfur, and nitrogen have attracted considerable attention due to their novel structural features and interesting reactivity. Recently, we have initiated a research program that is designed to prepare models for complexes involved in chemical vapor deposition (CVD) processes of early transition metal materials. Species containing metal-element multiple bonds have featured prominently in mechanistic conjecture about CVD reactions, although little hard evidence is available to back up such speculation. It was disclosed that excellent-quality thin films of titanium nitride can be prepared by the atmospheric pressure CVD reaction of titanium tetrachloride with alkylamines at temperatures between 350 and 600 {degrees}C. This process appeared ideal for detailed mechanistic scrutiny, since titanium tetrachloride is well-known to be highly reactive toward amines{sup 9} and because titanium should be capable of stabilizing a variety of nitrogen ligand types. In this context, we report the synthesis and characterization of two complexes that are formed in the solution-phase reactions of titanium tetrachloride with tert-butylamine. To the best of our knowledge, the first of these, a chloride-amide-amine complex, comprises the first single-source CVD precursor to high-quality gold-colored films of titanium nitride. Additionally, a monomeric imido complex has beenmore » trapped with triphenyl-phosphine oxide and has been structurally characterized. Evidence is presented from mass spectrometry for the intermediacy of imido complexes in the CVD process. The present results provide partial mechanistic insight into the sequence that leads from titanium tetrachloride and tert-butyl-amine to titanium nitride thin films. The system implies that imido complexes play an important role in other film forming processes.« less

A single-source precursor to titanium nitride thin films. Evidence for the intermediacy of imido complexes in the chemical vapor deposition process

Combined Experimental and Computational Investigation of the Mechanism of Nickel-Catalyzed Three-Component Addition Processes

Decaphenylstannocene, [.eta.5-(C6H5)5C5]2SnII: the first synmetrical main-group sandwich compound

Metals in anticancer therapy: Copper(II) complexes as inhibitors of the 20S proteasome

Transition-metal-promoted higher-order cycloaddition reactions are described. (η 6 -1,3,5-Cycloheptatriene)tri-carbonylchromium(0) and various substituted derivatives undergo photochemically or thermally initiated [6π+4π] cycloaddition with a range of substituted butadiene partners. Electron-rich and electron-deficient dienes participate equally well in the transformation, and in every case examined only the endo diastereomer was produced. The reaction displays little regioselectivity for 2- and 3-substituted cycloheptatriene complexes; however, most yields of products exceed 85%

Mary Jane Heeg

Papers

A single-source precursor to titanium nitride thin films. Evidence for the intermediacy of imido complexes in the chemical vapor deposition process

Combined Experimental and Computational Investigation of the Mechanism of Nickel-Catalyzed Three-Component Addition Processes

Decaphenylstannocene, [.eta.5-(C6H5)5C5]2SnII: the first synmetrical main-group sandwich compound

Metals in anticancer therapy: Copper(II) complexes as inhibitors of the 20S proteasome

Metal-promoted higher-order cycloaddition reactions. Stereochemical, regiochemical, and mechanistic aspects of the [6.pi. + 4.pi.] reaction