Explanation of the canonical set of molecular orbitals and assessment of the adequacy of mathematical representations for calculation of a wavefunction are just two examples of the many uses of computer-drawn diagrams of three-dimensional electron-density distributions.

A third possible way of combining two polymers—apart from blending and copolymerization—consists in the interpenetration of polymer networks.

A diamagnetic ring current persists in a variety of (4n+2)π compounds, whether cations, anions, or neutral molecules, even when the conjugated system is interrupted by one or more saturated centers.

All three possible stereoisomers are formed on light-induced decarbonylation of the complex (1) in the solid state and in solution at room temperature (detected by NMR spectroscopy). Spectra recorded immediately after dissolution of the crystalline transformation product reveal only the cis isomers.

The compounds hitherto regarded as benzoxetes (1) have proved to be oxepins (2). Structure (3) was ruled out by X-ray structure analysis of (2), R¹=tBu, R²R⁴Cl, R³OMe. This result appears particularly important with regard to oxidative coupling of phenols (biogenesis of phenolic natural products).

The first bis(cyclobutadiene) sandwich complex has now been synthesized and characterized. The complex forms blue crystals, is not attacked by boiling water in 24h, and can be reduced only with difficulty.

CO₂, allyl-nickel compounds, and phosphanes react quantitatively to give (oligomeric) nickel carboxylates with phosphane ligands. The results are most readily interpreted by assuming CO₂ insertion into an allyl-nickel σ-bond formed under influence of the phosphane.

Stable complexes of the new anion (1) have now been synthesized and characterized. In (3), MZn, Cd, Ni, all the Me₂PCH₂ groups are equivalent. X-Ray structure analysis shows the six-membered rings of the nickel compound to have a chair conformation.

Benzocyclobutadiene warrants particular interest owing to its intermediate position between cyclobutadiene and biphenylene. X-Ray structure analysis of the stable hexaalkyl derivative (1) showed the molecular skeleton to be planar and the ground state to be best described by the resonance structures (1 A) and (1 B); (1 B) has greater weight than (1 A).

Differing coordination of the cyclobutadiene ligand characterizes the isomeric complexes (1) and (2). It is the first system for which both isomers could be isolated. X-Ray structure analyses are available.

Adducts and heterocycles having NS bonds, e.g. the 1:1 adduct (2) with pyridine and the 1:2 cycloadduct (3) with benzonitrile, have now been obtained from the dimer of fluorosulfonylsulfimide (1). Analogous reactions should lead to a variety of new compounds.

The first cycloadditions involving allenyl cations (1) [eq. (a)] have now been accomplished with propargyl halides and cyclopentadiene. This reaction provides a convenient entry to the bicyclo[3.2.1]octane series.

The advantages of homogeneous and heterogeneous catalysis of olefin metathesis can be combined on use of the polymer-bound tungsten complex (1): activity and selectivity under mild conditions, on the one hand, and easy separation, regeneration, and especially repeated use, on the other.

Determination of the enantiomeric composition of chiral substrates is of considerable importance in many branches of chemistry, pharmacy, etc. 2,3-Epoxybutane has now been quantitatively resolved into three fractions, viz. the two trans forms and the cis form. This resolution by complexation gas chromatography requires neither derivatization nor extensive purification.

The theory of liquid crystals appears to require revision: the nematic properties of compounds of type (1), Rn-alkyl, were not predictable. On account of their particular physical properties, the new liquid crystals are of interest as anisotropic solvents for spectroscopy in ordered systems.

S₆O, the smallest known cyclopolysulfur oxide, has been prepared by oxidation of S₆ with trifluoroperacetic acid. Depending upon the conditions, either α- or β-S₆O is formed; the crystals differ in their physical properties.

The first X-ray structure analysis of a cyclotriarsane has now been accomplished. The As₃ ring bearing only aliphatic substituents is incorporated in a cage structure in this molecule. The three As—As contacts are almost equal and correspond to those in As₄.

A tetraazaphospholine (3), rather than a bridged triazaphosphetine (2), is formed on addition of (1) to tert-butyl azide; this was shown by X-ray structure analysis of (3), RSiMe₃, R′tBu. Still to be explained is the upfield shift of the ³¹P-NMR signal which can be regarded as an indication of fourfold coordination of the phosphorus.