Tag archive for research

Will research journals going web 2.0 really matter?

Cell published their first ‘Article of the Future‘ a couple of weeks ago; arstechnica has a good summary. The format, while new to scientific publishing, utilizes some of the better technologies that have been available on the web for most of the last decade.

It’s great that publishers are making research publications more accessible, especially to those outside the traditional scientific community, but I don’t believe it will impact the day-to-day workflow of most researchers. I, for one, ‘grew up’ with photocopies of papers organized in folders and binders, graduated to printed copies of pdfs (in folders by topic/project), and currently maintain a large DEVONthink database of pdfs, text clipped from articles, notes, etc., as well as assorted paper notebooks. I find RSS access much more useful that a ‘Web 2.0‘ format.

Overall, the broader impact is likely with the publishers as they adopt similar formats to comply with the NIH Public Access Policy, although there are other implications. MIT’s Open-Access Policy is worth reading as is the policy for the University of California system.

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MotW14 – A nonreducible, high-valent Mn(V) complex

MotW14-ic0609251-mol02wResearch involving the formation and characterization of high-valent Mn complexes has been slow. They are proposed to be active intermediates in biological and synthetic reactions, such as epoxidations and hydroxylations. They are also important intermediates in NR group transfer reactions, or pericyclic reactions in which a pi bond is  transformed into a sigma bond while another sigma bond migrates.

At John Hopkins University, a manganese(V) imido complex [(TBP8Cz)MnV(NMes)] was synthesized from the Mn(III) complex [(TBP8Cz)MnMIII]  (Lansky, D.; Kosack, J.; Narducci Sarjeant, A.; Goldberg, D. Inorg. Chem. 2006, 45, 8477-8479). Even with a high-valent MnV center, the complex is very resistant to reduction. The 1H-NMR spectrum showed a diamagnetic molecule, indicating a low-spin MnV (d2) species. The structure was confirmed via X-ray crystallography. The crystal contains two independent molecules, with the imido axial ligands pointing away from each other. A short Mn-N imido distance suggests a stronger pi overlap between the terminal imido ligand and the empty metal dxz/dyz orbitals. The metal ion is 0.55 Angstroms above the average plan of the four pyrrole N atoms.

Reactions of the Mn(V) complex with alkenes were unsuccessful. H-atom abstraction should be able to occur in this molecule, but it was completely unreactive toward even a highly reactive H-atom donor. This lack of reactivity shows that the complex cannot undergo even weak H abstraction. The explanation could be that the rate-determining step is the reduction of MnV to MnIV which is not easily reached, and therefore the thermodynamics do not favor the H abstraction. The complex is also very resistant to reduction, even as a high-valent species, as shown by the electochemical data.

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