Film studies : Epitaxial films of BaZrN2 (see TEM image) and BaHfN2 are grown by polymer‐assisted deposition on SrTiO3 (STO) substrates. The films are phase‐pure, allowing the intrinsic physical properties of the ternary nitrides to be studied. From 5 to 300 K, the films exhibit metallic‐like resistivity–temperature behavior, with large residual resistivity ratios.
All light and no heat? Structure–property relationships for photochromic and thermochromic N‐salicylideneanils have been revised (see picture). One derivative has a packed crystal structure, is photochromic and exhibits an infinitely slow thermal back relaxation of technological interest. Complexation of the anils to transition metals has also been studied.
Do the twist : The reaction of in situ generated phosphinidenes with phosphaalkynes is a facile route to the new metal‐coordinated η3‐diphosphavinylcarbene 1 , which shows facile ligand‐exchange reactions and undergoes an unprecedented rearrangement that involves phosphinidene complex 2 and η3‐phosphaalkenylphosphinidene complex 3 , the 1,3 isomer of 1 .
Polymer, heal thyself! Dynamic polymers formed by a reversible Diels–Alder reaction were formed and studied by using neutron scattering at room temperature. They were used to obtain thin films that displayed self‐healing at room temperature (see figure).
Bridge of Si's : Quantum‐chemical calculations suggest that the bonding situation in the recently synthesized “trisilaallene” is better described in terms of donor–acceptor interactions between two silylene ligands L and a naked silicon atom Si, which carries two lone‐pair orbitals, yielding the silylone SiL2. Further silylones SiL2 with different donor ligands Si have also been calculated, which might be possible to synthesize.
DNA hybrid catalysis goes organometallic : A DNA strand functionalized with diene ligands forms iridium(I) complexes that can efficiently catalyze an allylic amination in aqueous medium (see scheme). The DNA‐based complexes show high stability and activity, and their secondary structure influences the stereoselectivity of the reaction.
Stop the breathing : As the organic bridging ligands become more elaborate and large, the resulting MOFs tend to experience significant framework distortion (i.e., breathing) upon solvent removal. Rigidification of MOFs that are built from elongated tetracarboxylate bridging ligands by unusual interlocking and interpenetration leads to highly porous and robust hybrid materials.
All in one pot! Radical, radical–ionic, and radical–organometallic MCR are highly convergent processes, representing a useful pathway to molecular and structural diversity (see scheme). This concept article highlights recent developments in the field and shows the potential of the strategy for the economical elaboration of various kinds of organic substrates.
Translation of specific small peptides on the ribosome can confer resistance to macrolide antibiotics. To reveal the molecular details of this and related phenomena, stable RNA–peptide conjugates that mimic peptidyl‐tRNA would be desirable, especially for ribosome structural biology. A flexible solid‐phase synthesis strategy now allows efficient access to these highly requested derivatives without restriction on the RNA and peptide sequences.
The acidity‐enhancing effect of BH3 in gas‐phase phosphine ? boranes compared to the corresponding free phosphines is enormous, between 13 and 18 orders of magnitude in terms of ionization constants. Thus, the enhancement of the acidity of protic acids by Lewis acids usually observed in solution is also observed in the gas phase. For example, the gas‐phase acidities (GA) of MePH2 and MePH2 ? BH3 differ by about 118 kJ mol?1 (see picture).
Showing their true colors? Full emission color tuning in the visible region can be achieved with salen–aluminum complexes that are electronically modulated at C5 of the phenoxide ring in the salen moiety. Emission spectra for various substituents R5 are shown (EWG: electron‐withdrawing group, EDG: electron‐donating group).
Bicomponent supramolecular polymers , consisting of two alternating molecules bridged through six H‐bonds, are observed by STM at the solid–liquid interface. Control of the geometry of the 1D architecture was obtained by using two different connecting molecules with different conformational rigidity, affording either linear (see picture, left) or zigzag (right) motifs.
Tin knows its oniums! An unusual nitride tetrastannylene and a stannylenated ammonium ion stabilized by a samarium tetradiazaphospholido counterion are the first examples of a tris(organostannylenyl)amine derivative and a divalent tin coordinate onium ion that incorporates 1,2,4‐diazaphospholide ligand (see figure).
Twice as reactive : The coordination chemistry of phosphane‐functionalized Zr and Hf cycloheptatrienyl–cyclopentadienyl complexes gives rise to unusual secondary interactions associated with the presence of Lewis acidic 16‐electron sandwich moieties. These structures can develop weak dative bonds as exemplified by the noncovalent Pd→Zr interaction in the heterobimetallic {Zr2Pd} complex (see picture).
Three‐component coupling reactions of an alkyne, an enone, and a diboron reagent provide access to highly substituted alkenyl boronates in good to excellent yields (see scheme). The coupling is highly regio‐ and stereoselective, and the products are amenable to further functional‐group transformations. R1,R2=H, alkyl, aryl, CO2Me; R3=alkyl, Ph; R4,R5=H, alkyl.
Insensitive energetic salts : A series of furazan‐functionalized tetrazolate‐based energetic salts (see figure) were synthesized and characterized. All of the salts exhibit excellent thermal stabilities and high positive heats of formation.
Shine a light with cyanates : A novel approach for the synthesis of urea complexes and homoleptic cyanates of alkaline earth metals and europium is described. The compounds have been fully characterized, including their magnetism and temperature‐dependent luminescence properties (see graphic).
