Tetrathiafulvalene-acetylene scaffolding: new pi-electron systems for advanced materials

Novel extended tetrathiafulvalenes (TTFs) with hexa-2,4-diyne-1,6-diylidene spacers between the two 1,3-dithiole rings and laterally appended alkynyl moieties for one- and two-dimensional scaffolding were synthesised and investigated for their electronic properties.     

Fast-atom-bombardment and tandem mass spectrometry for determining structures of fatty acids as their picolinyl ester derivatives

Picolinyl ester derivatives of common fatty acids can be readily desorbed by fast atom bombardment (FAB) as positive ions and then collisionally activated. Collisionally activated spectra of the (M + H)⁺ ions of the derivatives reveal that structurally informative remote-charge-site fragmentations occur. The presence of substitutents such as double bond, branch points, cyclopropane rings, hydroxy groups, and epoxy rings interrupts the fragmentation process in such a way that the substituent can be identified and its location on the alkyl chain can be determined. This method is also applicable to the picolinyl esters of short-chain fatty acids and to the analysis of mixtures of fatty acid derivatives. The approach is advantageous becasue the epicolinyl ester derivatives are also amenable to gas chromatography/mass spectrometry (GC/MS). Therefore, the FAB-MS/MS approach developed here is complementary to GC/MS.     

Frequency-dependent linear response of superconducting systems

We present a density functional scheme for calculating the frequency-dependent linear response of superconductors. The central result is a set of integral equations determining the linear response of the normal and anomalous densities to external perturbations. Analytic solutions of these integral equations are obtained for homogeneous systems with separable effective interactions. For inhomogeneous superconductors, the formalism leads to a scheme for calculating the critical temperature without explicitly solving the gap equation. © 1995 John Wiley & Sons, Inc.