Don't rewrite the textbooks! Vibrational spectra of a selectively deuterated derivative of phenanthrene indicate that the C4HHC5 interaction in its "bay" area should be interpreted as steric (Pauli) repulsion. These findings and the results of theoretical analysis are in conflict with interpretations that describe this interaction as strongly stabilizing.

The new Lewis acid Al(OTeF ) and its acetonitrile adduct CH CN→Al(OTeF ) were obtained by a simple one-step synthesis in batches of up to 15 g. Al(OTeF ) and the adduct were characterized by vibrational spectroscopy (IR, Raman) and quantum-chemical calculations. Furthermore, five different salts of the new weakly coordinating anion [Al(OTeF ) ] were prepared in a two-step procedure. [Ph P][Al(OTeF ) ], Cs[Al(OTeF ) ], [Ph C][Al(OTeF ) ], as well as the protonated benzene derivatives [C H ][Al(OTeF ) ] and [C H ][Al(OTeF ) ] were characterized by low-temperature single-crystal X-ray diffraction and NMR spectroscopy. Arenium salts have rarely been characterized in the solid state and were synthesized in this work in a simplified fashion.

The previously recognized "extremely explosive" carbonyl diazide, OC(N(3))(2), was prepared as a pure compound and unambiguously characterized by gas-phase IR, matrix IR, and Raman spectroscopy and X-ray crystallography for the first time. The pure substance shows remarkable kinetic stability at room temperature in the gaseous, liquid, and solid states. A melting point of 16 °C and vapor pressure of 5.6 mbar at 0 °C were determined. Two planar conformers were found in the gas phase, and a composition of 12% anti-syn versus 88% syn-syn conformer in the gaseous equilibrium mixture at room temperature was estimated by matrix IR spectroscopy. In the crystal structure, only the more stable syn-syn conformer was observed. The preference of the syn-syn configuration was supported by DFT calculations.

Thermally persistent triplet sulfonyl nitrene, FSO(2)N, was produced in the gas phase in high yields (up to 66%) by flash vacuum pyrolysis of FSO(2)N(3). Surprisingly, no rearrangement of FSO(2)N was observed, but the long-sought radical FSO(2) (22%) and traces of SO(2) (3%) were identified by IR ((15)N, (18)O, (34)S) spectroscopy. The photoinduced Curtius rearrangement of the nitrene to FNSO(2) was observed in solid noble gas matrices, and reactions of the nitrene with O(2), NO, and CO were studied.

The synthesis of [NMe ][AuF ] and [NEt ][AuF ], as well as an improved one-pot synthesis of Cs[AuF ], is reported. The new [AuF ] salts were structurally characterized by single crystal X-ray diffraction, NMR spectroscopy, vibrational spectroscopy, and mass spectrometry. These salts are the first gold(III) fluoride salts that can be isolated in pure form and are convenient to be used in usual organic solvents for subsequent synthesis. The formation of molecular AuF complexes in solution is further reported, characterized as [F Au(NCCH )] at low temperature, as [F Au(py)] and a binuclear derivative which are stable at room temperature. The stability of these species in common organic solvents was investigated and they showed a satisfying stability.