A method is described to obtain multicollision dissociation threshold (MCDT) values. These values provide relative reaction thresholds for dissociation in the three major gas-phase fragmentation reactions of oligosaccharides complexed to alkali metal ions. The quasimolecular ions are produced using matrix-assisted laser desorption/ionization Fourier transform mass spectrometry. The MCDTs for al...

the complexation of alkali metal cations by the water-soluble p-sulfonic acid calix(4)arenewas thermodynamically characterized using spectrophotometeric data which are consistentwith the formation of a 1:1 complex resulting from electrostatic interactions between thesulfonato groups and alkali metal cations. in this study, we determined the formationconstants (log k) of the complexes and have c...

At ambient pressure there are 29 elemental superconductors in the periodic table, none of which is an alkali metal. The first alkali metal to become superconducting under high pressure is Cs followed years later by Li. Alkali metals are believed to be exemplary free-electron systems. The fact that an alkali metal becomes superconducting at all is surprising and is a result of the fact that unde...

The complexation of Alkali metal cations by the water-soluble p-sulfonic acid calix(4)arenewas thermodynamically characterized using spectrophotometeric data which are consistentwith the formation of a 1:1 complex resulting from electrostatic interactions between thesulfonato groups and alkali metal cations. In this study, we determined the formationconstants (log K) of the complexes and have c...

Alkali metal salts of thiocarboxylic acid, especially anhydrous salts, are of the most important starting materials. However, only a limited amount of information on their preparation and spectral data has been available because of their strong hygroscopicity [1]. Recently, the convenient preparation methods of a series of anhydrous alkali metal dithiocarboxylates were developed [2]. This resul...

We present a comprehensive theory of nuclear spin polarization of He and Xe gases by spin-exchange collisions with optically pumped alkali-metal vapors. The most important physical processes considered are ~1! spin-conserving spin-exchange collisions between like or unlike alkali-metal atoms; ~2! spin-destroying collisions of the alkali-metal atoms with each other and with buffer-gas atoms; ~3!...

the complexive abilities of 5,11,17-tddert-butyl-23 amino-25.26,27,28-tet3propoxy-calix[4]arere and5,1127-tri-amino-23 acelyktert-butylamide-25,26,27,28-tetrabutoxy-calixplarene towards alkali metalions lit nat, kt ric and cs+ in methanol-chloroform mixture have been evaluated at 25 °c, using uvvis spectrophotometric techniques. the results showed that the hgands are capable to complex with all...

Alkali metal compounds have been known since antiquity. In 1807, Sir Humphry Davy surprised everyone by electrolytically preparing (and naming) potassium and sodium metals. In 1808, he noted their interaction with ammonia, which, 100 years later, was attributed to solvated electrons. After 1960, pulse radiolysis of nearly any solvent produced solvated electrons, which became one of the most stu...

the do1(18c6)fi (mwli. na. k and i 8c6=18-crown-6) complexes have been chosen as the model systems toinvestigate the nature of chemical bonds between alkali metal cations and large mffitidentaie orgmnic ligands.the b3lyp/6-3i+g(d,p) level of calculation has been used for obtaining equilibrium geernetnes and p(r)functions (electron density distributions). by the aid of fundamental physical theor...

The collision-induced dissociation of lasalocid and monensin A bound to alkali metal cations has been investigated using electrospray MS/MS. The binding affinity for the metal cations, as measured with collision-induced dissociation, was found to depend on their ionic radius, decreasing with increasing radius. Monensin A was observed to have a greater binding affinity for alkali metal cations t...