Distance fingerprinting : Pulsed electron–electron double resonance spectroscopy (PELDOR) is applied to the octameric membrane protein complex Wza of E. coli. The data yielded a detailed distance fingerprint of its periplasmic region that compares favorably to the crystal structure. These results provide the foundation to study conformation changes from interaction with partner proteins.
Pincer carbene complexes : Comparison of the electronic structures of “pincer” Fe0 pyridine bis(imidazol‐2‐ylidene) and pyridine diphosphine dicarbonyl complexes (see figure) show subtle differences that account for observed spectroscopic trends. Intermolecular C? H activation has been observed in Fe pyridine dicarbene complexes.
Gold caps on silicon nanowires are selectively coated with silver by autometallography (electroless deposition). Changing the conditions of silver deposition, a variety of different coating morphologies can be produced (see figure). The different silver coating morphologies are investigated in terms of their capabilities for surface enhanced Raman scattering (SERS) experiments.
Reaction rates from polarized spectroscopy : A new method based on ultrafast pump–probe polarization spectroscopy enables the measurement of the ground‐ and excited‐state reaction rates for self‐exchange processes. The technique was used to study double hydrogen transfer in porphycene and its derivatives (see figure).
Shifts for crystals : Solid‐state NMR spectroscopy can be used for structure determination of microcrystalline paramagnetic solids at natural isotopic abundance. The protocol makes use of paramagnetic effects, measured on suitably recorded 1H NMR spectra, to define the conformation of a molecule in the lattice and the intermolecular packing in the solid phase. The method is illustrated with a family of lanthanide compounds (see picture).
Show me your angle : Incorporation of the rigid spin label Ç allows determination of both distance and orientation of two nitroxide spin labels in DNA by PELDOR experiments at common X‐band frequencies. The orientational information is obtained by varying the position of the detection pulses over the nitroxide spectrum. Simulation of the set of time traces yields very precise distances and angles.
From blue to red: While four π‐conjugated nitrophenolates absorb within a relatively narrow region in solution, they cover the entire visible spectrum when isolated in vacuo (see picture). The work combines gas‐ and solution‐phase spectroscopy and provides the first benchmark of theoretical excitation energies for nitrophenolates.
Telling the difference quickly: Femtosecond laser pulses are not only suitable to distinguish structural isomers. They also provide access to the distinction of enantiomers by combination of circular dichroism and mass spectrometry (see picture).
Symbiosis: Far‐infrared spectra can be used to check the quality of force fields for molecular dynamics simulations of ionic liquids. On the other hand, MD simulations can explain the molecular basis of measured properties for this new liquid material (see picture).
Close to the edge : Photoexcitation of alizarin coupled to the surface of mesoporous TiO2 films leads to ultrafast electron transfer to the TiO2 conduction band (see picture). Complex kinetics after photoexcitation depend on the excitation energy, and indicate a position of the alizarin excited state close to the TiO2 conduction band edge, where the density of acceptor states is reduced.
A variety of differently substituted 6‐ and 7‐arylchromenes such as that depicted undergo photoinduced C? O bond cleavage to yield colored o‐quinonoid intermediates. A combined analysis of μs–ms (laser flash) and real‐time kinetic data show that the o‐quinonoid intermediates decay faster when the C2‐aryl and C6‐/C7‐aryl rings contain electron‐donating and electron‐accepting groups, respectively. Similarly, the decay occurs slowly for the reversed scenario, while intermediate decay rates are observed when both substituents are electron donating.
Hex nut : An emerging synthetic approach based on metal–organic coordination‐polymer templates has been used to fabricate micro‐ and nanoscale crystals. By using a diverse range of molecular building blocks coupled with conventional synthetic techniques, it is possible to synthesize ZnO crystals with tailored sizes, shapes (such as hexagonal rings; see figure), and surface properties.
Seven in one blow : The efficient formation of mixed disulfides on the thiol‐rich fusion protein A followed by subsequent intein cleavage gave the fragment B with all seven cysteines protected against oxidation. The native chemical ligation of B with synthetic glycopeptide thioesters provides glycoproteins.
SERS you right: The plasmon heating of gold nanoshells is exploited to yield the local conversion of amorphous TiO2 into anatase on the surface of polymeric colloidal crystals (see scheme). The resulting Au/TiO2 spots are active substrates for surface‐enhanced Raman spectroscopy and allow surface reactions and processes to be followed directly on‐site.
