Selbstheilende Polymere

Even though the field of self‐healing is rarely known so far – self healing materials are already present at our market. Nevertheless just due to modern scientific concepts we are now able to understand the basic mechanistic steps in a more detailed way. Further progress on this field will open access to materials with a wide range of adjustable properties. Therefore, applications of such self healing materials are not limited – assuming the market‐price is competitive and the elongated lifetime delivers an appropriate advantage. Already demonstrated for concrete and clear coatings for cars, the investigations done so far have generated materials with improved properties and prolonged durability.     

Rotational Spectroscopy Probes Water Flipping by Full Fluorination of Benzene

The topology of the interaction of water with benzene changes drastically upon full H→F substitution on the aromatic ring: the weak O−H⋅⋅⋅π hydrogen bond is replaced by a O⋅⋅⋅π linkage, of about the same strength. Hexafluorobenzene–water appears to be the prototype system to investigate this kind of weak bond. The pulsed Fourier transform microwave technique has been used for the detection of the rotational spectra of the normal species and five isotopologues which unambiguously led to the identification of the geometry. Quantum mechanical calculations have been performed to interpret the experimental evidence.     

Silylene–Nickel Promoted Cleavage of B−O Bonds: From Catechol Borane to the Hydroborylene Ligand

The first 16 valence electron [bis(NHC)](silylene)Ni⁰ complex 1 , [(^TMSL)ClSi:→Ni(NHC)₂], bearing the acyclic amido‐chlorosilylene (^TMSL)ClSi: (^TMSL=N(SiMe₃)Dipp; Dipp=2,6‐Prⁱ₂C₆H₄) and two NHC ligands (N‐heterocyclic carbene=:C[(Prⁱ)NC(Me)]₂) was synthesized in high yield and structurally characterized. Compound 1 is capable of facile dihydrogen activation under ambient conditions to give the corresponding HSi‐NiH complex 2 . Most notably, 1 reacts with catechol borane to afford the unprecedented hydroborylene‐coordinated (chloro)(silyl)nickel(II) complex 3 , {[cat(^TMSL)Si](Cl)Ni←:BH(NHC)₂}, via the cleavage of two B−O bonds and simultaneous formation of two Si−O bonds. The mechanism for the formation of 3 was rationalized by means of DFT calculations, which highlight the powerful synergistic effects of the Si:→Ni moiety in the breaking of incredibly strong B−O bonds.