Spectroscopic consequences of varying the twist angle of the amino group in aminobenzonitrile systems in the electronic ground state are investigated by applying electron energy loss (EEL) spectroscopy and density functional theory to 4-N,N-dimethylaminobenzonitrile (DMABN), 4-N,N-dimethylamino-3,5-dimethylbenzonitrile (MMD), benzoquinuclidine (BQ), and 6-cyanobenzoquinuclidine (CBQ). A number of singlet and triplet excited states was observed and assigned with the help of DFT/SCI theory. The results characterize the gas-phase spectroscopy of the molecules and verify to within 0.3 eV the predictive power of DFT/SCI theory for vertical states over a wide range of twist and pyramidalization angles. The amino group configuration in the relaxed charge-transfer state of dual fluorescent aminobenzonitriles in solution cannot be directly deduced from the present data, however.

NADH-dichlorophenol-indophenol oxidoreductases (PMOs) were purified from synaptic plasma membranes or synaptic vesicles (small recycling vesicles) from both bovine and rat brains and from a neuroblastoma cell line, NB41A3. Several isoforms could be identified in purified plasma membranes and vesicles. Purification of the enzyme activity involved protein extraction with detergents, (NH4)2SO4 precipitation, chromatography under stringent conditions and native PAGE. PMO activity could be attributed to a very tight complex of several proteins that could not be separated except by SDS/PAGE. SDS/PAGE resolved the purified complex into at least five proteins, which could be micro-sequenced and identified unambiguously as hsc70, TOAD64 and glyceraldehyde-3-phosphate dehydrogenase tightly associated with the brain-specific proteins aldolase C and enolase-gamma. Enzyme activity could be purified from both synaptic plasma membranes and recycling vesicles, yields being much greater from the latter source. Highly purified plasma membranes (prepared from a neuroblastoma cell line NB41A3 by iminobiotinylation of intact cells and affinity purification with avidin and anti-avidin antibodies under very stringent conditions) also displayed PMO activity tightly associated with TOAD64. The association of PMO in a tight complex was confirmed by its immunoprecipitation from cellular and membrane extracts of NB41A3 using antibodies directed against any component protein of the complex followed by immunodetection with antibodies directed against the other members. Antibodies also inhibited the enzyme activity synergistically. In addition, induction of the different components of the complex during dichlorophenol-indophenol stress was demonstrated by the S1 RNase-protection assay in synchronized NB41A3 cells. The role of the complex in membrane fusion and cellular response to extracellular oxidative stress during growth and development is discussed.

Relative yields of C1-and Br-(X-) from dissociative electron attachment to o-, m-, and p-ClC&CHZBr and BrC&CHzCl have been measured as a function of the incident electron energy in the gas phase. A C1-or Br-signal was observed for all compounds at incident electron energies of 0-1 eV, corresponding to electron attachment to n* orbitals followed by dissociation. Bond breaking is highly selective; the yield of the benzylic X-is always substantially higher than the yield of the phenylic X-at incident energies below 1 eV. The selectivity is explained by the weaker benzylic CX bond and by symmetry restrictions in x*h* orbital coupling, making the dissociative intramolecular electron transfer from the benzene n* MO into the benzylic CX bond faster than into the phenylic CX bond. A second (weaker) X-band is observed in some compounds at incident electron energies around 4.5 eV. The former selectivity of bond breaking is reversed at this incident energy, indicating a different electronic symmetry of the incipient radical anion state.

We have reported the syntheses of the n = 11 and 22 members of a homologous series of pyramidalized alkenes (l),3 their spectroscopic study in matrix isolation,4-5 and some of their chemistry.6 The generation of a benzo derivative of 1, n = 2,7 and a bis-ethano derivative of the n = 0 member of this series have also been described.8 In this communication we report the synthesis and some spectroscopy of 1, n = 3.

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