The gas-phase structures of alkali metal cation-cytosine complexes generated by electrospray ionization are probed via infrared multiple photon dissociation (IRMPD) action spectroscopy and theoretical calculations. IRMPD action spectra of five alkali metal cation-cytosine complexes exhibit both similar and distinctive spectral features over the range of ~1000-1900 cm(-1). The IRMPD spectra of t...

synthesis and cation selectivity of 25, 27, dipropoxy-26, 28, di-propoxy 5, 11, 17, 23, ptert-butyl calix[4]arene are studied in acetonitrile solution. the stability constants of differentcomplexes of calixarene (as a ligand) with alkali metal cations are determined at 25 °c by usingspectrophotometric technique.on the basis of calculations, complexation of calixarene with cs+and li+ are more fa...

Synthesis and cation selectivity of 25, 27, dipropoxy-26, 28, Di-propoxy 5, 11, 17, 23, ptert-butyl Calix[4]arene are studied in acetonitrile solution. The stability constants of differentcomplexes of Calixarene (as a ligand) with alkali metal cations are determined at 25 °C by usingspectrophotometric technique.On the basis of calculations, complexation of Calixarene with Cs+and Li+ are more fa...

The alkali metal ion affinity of guanine quadruplexes has been studied using dispersion-corrected density functional theory (DFT-D). We have done computational investigations in aqueous solution that mimics artificial supramolecular conditions where guanine bases assemble into stacked quartets as well as biological environments in which telomeric quadruplexes are formed. In both cases, an alkal...

The alkali metal cations Na(+) and K(+) have several important physiological roles, including modulating enzyme activity. Recent work has suggested that alkali metal cations may be coordinated by pi systems, such as the aromatic amino acid side chains. The ability of K(+) to interact with an aromatic ring has been assessed by preparing a family of synthetic receptors that incorporate the aromat...

Alkali metal cations can interact with Fe-N2 complexes, potentially enhancing back-bonding or influencing the geometry of the iron atom. These influences are relevant to large-scale N2 reduction by iron, such as in the FeMoco of nitrogenase and the alkali-promoted Haber-Bosch process. However, to our knowledge there have been no systematic studies of a large range of alkali metals regarding the...

When adsorbed (at a low temperature) on alkali-metal-exchanged zeolites, CO forms both M(CO) and M(OC) carbonyl species with the extra-framework alkali-metal cation of the zeolite. Both quantum chemical and experimental results show that C-bonded adducts are characterized by a C−O stretching IR band at a frequency higher than that of 2143 cm for free CO, while for O-bonded adducts this IR band ...

The first addition of alcohols to carbodiimides catalyzed by transition-metal-free compounds employs 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) and its alkali metal salts. Isoureas are obtained in short reaction times and high yields when TBDK is used as the catalyst. Control of the coordination sphere of potassium with exogenous chelating ligands, in combination with mechanistic DFT calculation...

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...

We report the first direct solution NMR detection of the alkali metal cations (23Na+, 39K+, and 87Rb+) residing inside G-quadruplex channel structures formed by guanosine 5'-monophosphate and a DNA oligomer, d(TG4T). In solution, these channel alkali metal cations are tightly bound to the G-quadruplex structure and have been considered to be "invisible" to NMR spectroscopy for many years. Our f...