“What is KRI?” – R&D based on excellent tradition and innovation –

As far as KRI's clients were concerned, KRI's appeal was not only in having researchers who had a high level of expert knowledge, but it was also in the efficiency with which high risk jobs were conducted, and the speed of response time, especially when corporations made comparisons with their own in‐house labs. KRI, while being a facility for contract research, is also capable of becoming a profitable corporation, mostly thanks to the adoption of this system. KRI sincerely hopes to continue serving as a group made up of quality professionals who embrace a dream, and to contribute to society through its achievements. At the same time, the company strives to be sensitive to changing needs, and, of course, to conduct R&D and consulting activities which will ensure success for its clients.     

Secododecahedradienes – Syntheses,Reactivity, in‐Plane Homoconjugated 3C/2e Cations, 4C/3e Radical Cations,and σ‐Bishomoaromatic 4C/2e Dications?

Secodecahedradiene 2a , featuring very proximate, perfectly syn‐periplanar and significantly pyramidalized C=C bonds, was synthesized as testing object for in‐plane(σ)‐homoconjugational electron delocalization, starting from the available pagodane 15b . The response of 2a (and in part its diester 2b ) – in π,π‐distance (average 3.08 Å), olefinic pyramidalization (average 26.9°), and π,π‐split (PE, 1.15 eV) intermediate between disecododecahedradiene 1a and 1,16‐dodecahedradiene 3a – to selected 4π‐reagents, electrophiles, and radicals was explored experimentally and by calculations. Intriguing multistep reaction sequences attest to the ease of competing stabilization pathways for the 3C/2e in‐plane homoconjugated cationic intermediates. PE, CV, and ESR measurements and calculations (DFT) characterize the radical cation generated from 2a as in‐plane homoconjugated 4C/3e‐species 2a ^.+, persistent in a Freon matrix, but only very shortly existent in solution (CIDNP). Consequently, NMR control of the two‐electron oxidation in SbF₅/SO₂ClF did not disclose the σ‐bis‐homoaromatic dication 4C/2e (see 2a ^{2 +} ), but a bis‐allylic dication 75 as persistent species. In support of 2a ^{2 +} as intermediate, evidence is presented for very limited kinetic protection offered by the secododecahedral framework to through H‐cage σ‐homoconjugated cations.     

Zur Kenntnis von Oxyden A[MO4]: Über LiMnO4, KMnO4, RbMnO4, CsMnO4 sowie RbIO4 und CsIO4. (– Was heißt eigentlich “Die Kristallstruktur von …”? –)

On the Knowledge of Oxides A[MO₄]: On LiMnO₄, KMnO₄, RbMnO₄, CsMnO₄ as well as RbIO₄, CsIO₄. (– What does “The Crystal Structure of …” mean? –) These investigations confirm again that, sufficient purity, symmetry and lack of disorder etc. of investigated single crystals provided: the structure of a solid is characterized only if a) lattice constants are determined precisely by powder data; b) a couple of single crystals is sufficiently investigated by film data; c) the “quantitative” comparison of crystal structures of a chemical series like A[MnO₄] with another one like A₂[SO₄] alone enables one to estimate the quality of different structural investigations of the same material. d) ” The ” crystal structure of a solid is still non-existent.     

Silicon‐Containing Formal 4π‐Electron Four‐Membered Ring Systems: Antiaromatic,Aromatic, or Nonaromatic?

Density functional theory calculations (B3LYP) have been carried out to investigate the 4π‐electron systems of 2,4‐disila‐1,3‐diphosphacyclobutadiene (compound 1 ) and the tetrasilacyclobutadiene dication (compound 2 ). The calculated nucleus‐independent chemical shift (NICS) values for these two compounds are negative, which indicates that the core rings of compounds 1 and 2 have a certain amount of aromaticity. However, deep electronic analysis reveals that neither of these two formal 4π‐electron four‐membered ring systems is aromatic. Compound 1 has very weak, almost negligible antiaromaticity, and the amidinate ligands attached to the Si atoms play an important role in stabilizing this conjugated 4π‐electron system. The monoanionic bidentate ligand interacts with the conjugated π system to cause π‐orbital splitting. This ligand‐induced π‐orbital splitting effect provides an opportunity to manipulate the gap between occupied and unoccupied π orbitals in conjugated systems. Conversely, compound 2 is nonaromatic because its core ring does not have a conjugated π ring system and does not fulfill the requirements of a Hückel system.