Synthesis and Reactivity of the Phosphorus Analogues of Cyclopentadienone,Tricyclopentanone, and Housene

The phosphorus analogues of cyclopentadienone, tricyclopentanone, and housene were accessed from bis(cyclopropenyl)diphosphetanedione 3 , which was prepared by mixing 1,2,3‐tris‐tert‐butylcyclopropenium tetrafluoroborate ( 1 ) and sodium phosphaethynolate [Na(OCP)(dioxane)_n]. While photolysis of 3 results in decarbonylation, yielding bis(cyclopropenyl)diphosphene 4 and after rearrangement diphosphahousene 5 , thermolysis of 3 leads to phosphatricyclo[2.1.0.0]pentanone 7 . Metal‐mediated valence isomerization of 7 and subsequent demetalation provides access to phosphacyclopentadienone 12 .     

Vergleichende Untersuchungen zur Struktur von 4‐Dimethylaminopyridin‐Addukten

Comparative Structural Studies on 4‐Dimethylaminopyridine‐Adducts Lewis acid‐base adducts of the type dmap—MMe₃ (M = Al 1 , Ga 2 , In 3 , Tl 4 ) as well as dmap—AlCl₃ ( 6 ) and dmap—Al(t‐Bu)₃ ( 7 ) were synthesized by reaction of MR₃ with 4‐dimethylamino‐pyridine (dmap) whereas dmap—AlH₃ ( 5 ) was obtained from AlH₃·Et₂O. 1 — 7 were characterized by means of NMR (¹H, ¹³C{¹H}) and mass spectrometry and elemental analysis. In addition, their solid state structures were determined by single crystal X‐ray diffraction studies. A comparison of the structural parameters reveales the influence of both electronic (Lewis acidity of the group 13 atom) and steric interactions on the structure and stability of as prepared Lewis acid‐base adducts.     

Experimental and theoretical treatment of hydrogen splitting and storage in boron-nitrogen systems

Hydrogen gas serves as a reducing agent and hydrogen atom source in numerous industrially important chemical processes and also has a great potential as a clean power source for fuel cells. In this respect, the reversible storage of hydrogen and the development of new metal-free hydrogenation catalysts are important tasks. Here, we review the recent literature, primarily on cases where the split H₂ forms an N-H?H-B dihydrogen bond. In these systems dihydrogen interaction was found to be the key actor in the hydrogen liberating process. Accordingly, the intramolecular ansa-aminoboranes (where B and N atoms are situated within each other’s range) can reversibly activate hydrogen. Moreover, the theoretical studies of the hydrogen splitting by bulky Lewis acid-Lewis base systems are discussed.     

Preparation and molecular structure of 2,6‐dimesitylphenyldichlorophosphane

Owing to steric congestion, the phosphane unit within the title compound is dislocated from the central position which is associated with a difference in the P? C? C angles of 20.3(2)° and a compression of the Cl bond distance of the chlorine atom involved in this repulsive interaction. Copyright © 2006 John Wiley & Sons, Ltd.     

[N‐(Benzyl­idene)­aniline‐N]­pentacarbonyl­chromium(0)

In the title compound, [Cr(C₁₃H₁₁N)(CO)₅], the imino ligand displays weak π‐acceptor capabilities and, in contrast to Fischer‐type carbene complexes, is not positioned on the bisecting line of the angle between two CO ligands.