Synthese und Basizität 4-heterosubstituierter. Chinuclidine Chinuclidinreihe, 13. Mitteilung

The preparation of several 4-heterosubstituted quinuclidines and the pK_a values of their hydroperchlorates in water are reported.     

SCF MO LCGO studies on the hydration of ions: The systems H+H2O,Li+H2O,and Na+H2O

The energy surfaces of the systems LiOH ₂ ⁺ and NaOH ₂ ⁺ are studied for a number of different geometries within the SCF MO LCAO framework, using a gaussian basis set to approximate the wavefunction. In the minimum energy geometry of both systems the positive ion is bound to the oxygen atom of the water molecule. The computed binding energies and bond distances are: B ^SCF(LiOH ₂ ⁺ ) = 36.0 kcal/mole, d(LiO) = 3.57 a.u., and B ^SCF(NaOH ₂ ⁺ ) = 25.2 kcal/mole, d(NaO) = 4.23 a.u., resp. The results are compared with those of H₃O⁺ and discussed in view of ion-solvent interaction in aquous solutions.It is a pleasure to thank our technical staff for the careful preparation of the input for the programs and for its enthusiastic and skilful assistance in running the computer.     

Carbonylierung von bis(triphenylphosphin)-platin(II)- und -palladium(II)-komplexen in gegenwart von aminen und α-aminosäureestern

The crystal structure of (C₅H₅)₃Pr·CNC₆H₁₁ was determined from single-crystal X-ray diffraction data. The monoclinic unit cell of dimensions a = 8.298(3), b = 21.66(1), c = 11.943(4) Å, and β = 104.98(3)° contains four molecules in general positions of space group P2₁/c. Each molecule is composed of three C₅H₅ rings in a nearly exact trigonal array, η⁵-bonded to the Pr atom at a distance of 2.53 Å to the centroid of each ring, plus a single CNC₆H₁₁ adduct attached to the Pr atom along the trigonal axis at 2.65 Å. The presence of a CN triple bond in the isonitrile moiety and the nearly linear CNC configuration add credence to the previous proposal that there is a pure donor bond from the isonitrile carbon to the metal atom.     

The electronic structure of molecules by a many-body approach

The vertical valence ionization potentials of cyclopropane, ethylene oxide and ethylene imine are calculated by a many-body Green's function method. For C₃H₆ the ordering of the ionization potentials is 2e(), 1e(), 2a₁(), 1a₂(), 1e(). The assignment of the 2a₁ and the 1a₂ ionization potentials which has been controversial is thus clarified. The ordering is in agreement with the result obtained via Koopmans' theorem. For ethylene oxide and ethylene imine Koopmans' theorem fails in predicting the correct order of ionic states. For C₂H₄O the ordering of the ionization potentials is 2b ₁(), 4a ₁, 1a ₂(), 2b ₂,3a ₁, 1b ₁(), 1b ₂, 2a ₁ and for C₂H₅N 6a, 5a, 3a, 2a, 4a, 3a, 1a, 2a. The agreement of the computed ionization potentials with the experimental values is very satisfactory.