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The gas-phase basicities of the title compounds have been determined by Fourier transform ion cyclotron resonance mass spectrometry. Arsines are systematically weaker bases than phosphines. Basicity decreases in both series in the order ethyl > ethenyl > ethynyl. On the basis of their ionization energies, the phosphorus atom is recognized as the preferred site of protonation in the phosphines studied. A similar reasoning applied to arsines does not allow a clear-cut conclusion to be made. As it appears from the experimental results of this study and the few data on alkyl and phenyl derivatives available in the literature, substituent effects are attenuated by a factor of approximately 1.15 when going from phosphines to arsines.

What is the role played by amino acids in the chemistry of the interstellar medium and the emergence of life on the early Earth? Are they really the primary key compounds as free amino acids? Is their presence or absence in the interstellar medium a significant problem? How to get an amino acid sample with an enantiomeric excess on the early Earth or ISM? How to increase the enantiomeric excess to have pure enantiomers? All these questions have received partial answers but they remain open and probably they will still be open for several more decades.

α,α′-dichlorophophines, easily obtained by chemoselective reduction of the corresponding phosphonates, can be considered as precursors of unhindered C-chlorophosphaethylenes and synthetic equivalents of phospha-acetylenes.

In the title compound, {2-[(dimethylamino-κN)-methyl]phenyl-κC}(4-diphenylphosphino-κP-3-methyl-1-phenyl-5-pyrazololato-κO)palladium(II) 0.5-benzene solvate, [Pd(C 22 H 18 N 2 OP)(C 9 H 12 N)].0.5C 6 H 6 , the Pd atom, which is in a quasi-planar environment, is complexed by two chelating three-electron-donor ligands, with P and N atoms occupying trans positions. The plane defined by the aromatic pyrazole ring is coplanar with the metal plane. The angle between the N-bonded phenyl ring and the metal plane is 8 o

International audience; About 160 molecules have been detected in the interstellar medium, the comae and the atmospheres of planets. The presence of these compounds leads to imagine a chemistry of these media to explain the formation of these species and to predict the possible presence of other ones. Many of them have never been synthesized or isolated in labs and their preparation can be challenging, up to necessitate news reactions or special equipments.

α,α′-dichlorophophines, easily obtained by chemoselective reduction of the corresponding phosphonates, can be considered as precursors of unhindered C-chlorophosphaethylenes and synthetic equivalents of phospha-acetylenes.

α-Dichlorophosphine (3), easily obtained by chemoselective phosphonate reduction, is a precursor of the unhindered C-chlorophosphaethylene (4) and a synthetic equivalent of the phospha-acetylene (5).

Reactive methyleneamines bearing alkyl or functional groups are isolated at low temperature in the condensate state by flash vacuum thermolysis of α-aminonitriles and subsequent vapour phase HCN removal on solid base.