?The biggest challenge facing scientists is finding a way to make clean energy. If I could have dinner with three famous scientists from history, they would be Marie Curie, Dmitri Mendeleev, and Henri Moissan. …?“ This and more about Véronique Gouverneur can be found on page 3559.
All wrapped up : The reaction of a 22‐membered macrocycle derived from bis(o‐formylphenyl)mercury and 1,2‐phenylenediamine with palladium(II) results in cleavage of the macrocycle and concomitant formation of a trimetallic complex (see picture; phenyl rings truncated for clarity). The nature of the HgII???PdII???HgII interaction was investigated by theoretical studies.
Iron man or weakling? Ligand‐field strengths are conveniently expressed by the empirical spectrochemical series. Although cyanide has been deeply entrenched as a strong‐field ligand, a couple of recent examples cast doubt toward the position of this ligand, namely the high‐spin (S=2) states of [CrII(CN)5]3? and [FeII(tpp)(CN)]?. tpp=meso‐tetraphenylporphinate.
Changing channels : The novel dynamic gas‐separation mechanism is demonstrated by a GC study for a flexible single crystal [Cu2(bza)4(pyz)]n, 1 . The single‐crystal host 1 , because of its flexibility, can separate various gases by adjusting its channel structure according to the features of the guest gaseous molecules.
?My most exciting discovery to date has been always the last one (or better still, the next one). The biggest challenge facing scientists is the responsible use of knowledge and scientific power for the betterment of humanity. …?“ This and more about P. Melchiorre can be found on page 3389.
Total synthesis through block glycosylation and selective chemical O‐sulfation of tyrosine residues yielded the glycopeptide recognition domain A (X=SO3?) of the P‐selectin glycoprotein ligand 1, in which the terminal sialic acid of the complex hexasaccharide side chain was replaced by (S)‐cyclohexyl lactic acid. In binding assays the O‐sulfated structure A showed high affinity towards P‐selectin, the non‐sulfated towards E‐selectin.
Electron by electron : β‐Diketiminato nickel(I) complex fragments are capable of activating N2 through coordination. The resulting complex can be reduced in two single‐electron steps, which further activates the N? N bond. The picture shows the structure of the singly reduced complex with μ‐η1:η1‐bound N2.
How low can you go? An FeII4 square was prepared by self‐assembly and exhibits both thermally induced and photoinduced spin crossover from a system with four high‐spin (HS) centers to one with two high‐spin and two low‐spin (LS) centers. The spin‐crossover sites are located on the same side of the square, and the spin transition and magnetic interactions (see picture) are synergistically coupled.
A different drummer : The existence of endohedral germanium clusters was predicted earlier by gas‐phase experiments. The [Co@Ge10]3? anion now synthesized is surprising, as it breaks with a long line of exclusively deltahedral structures found in the past. Instead, it has a regular pentagonal‐prismatic structure (see picture; Co gray, Ge red).
Additional cyclization : Dicyanonitrosomethanide, [C(CN)2(NO)]? undergoes nucleophilic addition and cyclization of 1,2‐diaminoethane and 1,3‐diaminopropane on the nitrile groups to form imidazolinyl and 1,4,5,6‐tetrahydropyrimidinyl groups, respectively. Ethanolamine has lower reactivity and fails to cyclize.
An sp 2 /sp 3 get‐together : A novel and efficient method can be used to synthesize 3,3‐disubstitued oxindoles by the direct intramolecular oxidative coupling of an aryl C? H and a C? H center (see scheme; DMF=N,N‐dimethylformamide).
POM alert : The incorporation of an amide oxygen atom into the framework of the Dawson‐type polyoxometalate (POM) cluster [P2V3W15O62]9? (see picture) allows the communication of electronic effects between the organic and the inorganic parts of the molecule, including fine‐tuning of the redox properties of the entire hybrid POM by the organic components, and transmission of the POM's electron‐attracting properties to the organic moiety.
Ein Phosphoranalogon des Komplexes Bis(η4‐cyclobutadien)eisen(0) wird von K. Lammertsma et al. in ihrer Zuschrift auf S. 3150 ff. vorgestellt. Im Hintergrund des Titelbilds posiert John Montagu (1718–1792), 4th Earl of Sandwich und Erster Lord der Admiralität, der es sich sicherlich nicht hätte träumen lassen, dass eines Tages eine wichtige Klasse von Organometallverbindungen nach ihm benannt werden würde. Die Synthese von [Fe(P2C2tBu2)2] belegt, dass die Sandwich‐Komplexe immer noch ein aktuelles Forschungsgebiet sind.
Hooking up : FeCl2 catalyzes the efficient cross dehydrogenative arylation of substrates having benzylic C? H bonds (see scheme). High regioselectivity was observed during the cross‐coupling between compounds containing aromatic C(sp2)? H bonds and benzylic C(sp3)? H bonds. This process is proposed to proceed by single‐electron‐transfer oxidation and Friedel–Crafts alkylation.
Ring any bells? The differential capacitance curve of Au(100) in neat [BMI]BF4 (BMI=1‐butyl‐3‐methylimidazolium) ionic liquid has a bell‐shaped feature (see picture). The adsorption of BMI+ shows a disorder–order transition and depends on the structure of the surface. Ordered adsorption in a micelle‐like structure stabilizes the underlying Au surface.
Metallica : A large contraction of the Pt? Pt bond in the triplet excited state of the photoreactive [Pt2(P2O5H2)4]4? ion is determined by time‐resolved X‐ray absorption spectroscopy (see picture). The strengthening of the Pt? Pt interaction is accompanied by a weakening of the ligand coordination bonds, resulting in an elongation of the platinum–ligand bond that is determined for the first time.
Schließen und öffnen : N‐Boc‐N‐alkylsulfamide sind geeignete Substrate für die Titelreaktion. Die oxidative Cyclisierung im ersten Schritt ist hoch chemoselektiv sowie stereospezifisch und diastereoselektiv. Mit neuen Verfahren zur Öffnung der dabei erhaltenen Sechsringheterocyclen werden unterschiedlich geschützte 1,3‐Diamine zugänglich (siehe Schema).
