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Henry Rzepa's Blog

Henry Rzepa's Blog
Chemistry with a twist
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Interesting Chemistry3D Colour Printing3D PrintingBob HansonChemical ModelsKimya Bilimleriİngilizce
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We have been experimenting with full-colour 3D printing of molecular objects. I thought I might here share some of our observations. Firstly, I list the software used: Crystal structures as sources of ball&stick models ( e.g. the CCDC database). Gaussian style cube files for sources of wavefunctions.

Interesting ChemistryAbove Energy DiagramEnergyEnergy TransferEnergy Transfer OccurringKimya Bilimleriİngilizce
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The ultimate reduction in size for an engineer is to a single molecule. It’s been done for a car; now it has been reported for the pixel (picture-element).[cite]10.1021/ja404256s[/cite] The molecule above (X=O, NR, R=aryl, etc) has been shown to be capable of acting as a molecular pixel.

Interesting ChemistryKimya Bilimleriİngilizce
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This potential example of a molecule on the edge of chaos was suggested to me by a student (thanks Stephen!), originating from an inorganic tutorial. It represents a class of Mo-complex ligated by two dithiocarbamate ligands and two aryl nitrene ligands (Ar-N:). I focus on two specific examples[cite]10.1039/A907382E[/cite], where R=R’ = H or Me, with crystal structures available for both.

Interesting ChemistryCambridgeChemical ReasonsMetalMetal SulfidesKimya Bilimleriİngilizce
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I noted previously that some 8-ring cyclic compounds could exist in either a planar-aromatic or a non-planar-non-aromatic mode, the mode being determined by apparently quite small changes in a ring substituent. Hunting for other examples of such chemistry on the edge, I did a search of the Cambridge crystal database for metal sulfides.

Interesting ChemistryKimya Bilimleriİngilizce
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The butterfly effect summarises how a small change to a system may result in very large and often unpredictable (chaotic) consequences. If the system is merely on the edge of chaos, the consequences are predictable, but nevertheless finely poised between e.g. two possible outcomes. Here I ask how a molecule might manifest such behaviour. Two examples of the molecule above are known, differing only in the nature of the R group.

HypervalencyInteresting ChemistryChemical ShiftMetal AtomsMetal CarbideKimya Bilimleriİngilizce
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A feature of a blog which is quite different from a journal article is how rapidly a topic might evolve. Thus I started a few days ago with the theme of dicarbon (C 2 ), identifying a metal carbide that showed C 2 as a ligand, but which also entrapped a single carbon in hexa-coordinated mode.

Chemical ITEnergy GapEnergy LevelsGoogleHarvardKimya Bilimleriİngilizce
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The title of this post summarises the contents of a new molecular database: www.molecularspace.org[cite]10.1021/jz200866s[/cite] and I picked up on it by following the post by Jan Jensen at www.compchemhighlights.org (a wonderful overlay journal that tracks recent interesting articles). The molecularspace project more formally is called “ The Harvard Clean Energy Project: Large-scale computational screening and design of organic

HypervalencyInteresting ChemistryEnergyGas PhaseKnudsenKimya Bilimleriİngilizce
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A comment made on the previous post on the topic of hexa-coordinate carbon cited an article entitled “ Observation of hypervalent CLi 6 by Knudsen-effusion mass spectrometry ”[cite]10.1038/355432a0[/cite] by Kudo as a amongst the earliest of evidence that such species can exist (in the gas phase). It was a spectacular vindication of the earlier theoretical

Interesting ChemistryMetalMetal CoordinatingOs-CKimya Bilimleriİngilizce
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C 2 (dicarbon) is certainly interesting from a theoretical point of view. Whether or not it can be described as having a quadruple bond has induced much passionate discussion[cite]10.1038/nchem.1263[/cite],[cite]10.1002/anie.201208206[/cite],[cite]10.1002/anie.201301485[/cite],[cite]10.1002/anie.201302350[/cite]. Its occurrence in space and in flames is also well-known.