Homoleptic acetonitrile complexes [Gd(CH3CN)9][Al(OC(CF3)3)4]3 and [Eu(CH3CN)9][Al(OC(CF3)3)4]2 have been studied in anhydrous acetonitrile by 14N- and 1H NMR relaxation as well as by X- and Q-band EPR. For each compound a combined analysis of all experimental data allowed to get microscopic information on the dynamics in solution. The second order rotational correlation times for [Gd(CH3CN)9]3+ and [Eu(CH3CN)9]2+ are 14.5 ± 1.8 ps and 11.8 ± 1.1 ps, respectively. Solvent exchange rate constants determined are (55 ± 15) × 106 s–1 for the trivalent Gd3+ and (1530 ± 200) × 106 s–1 for the divalent Eu2+. Surprisingly, for both solvate complexes CH3CN exchange is much slower for the less strongly N-binding acetonitrile than for the more strongly coordinated O-binding H2O. It is concluded that this exceptional behavior is due to the extremely fast water exchange, whereas the exchange behavior of CH3CN is more regular. Electron spin relaxation on the isoelectronic ions is much slower than on the O-binding water...
The two enantiomers of 2-(2-hydroxybiphenyl-4-yl)propanoic acid ((S)- and (R)-BPOH) have been selected as probes for human serum albumin (HSA). Photophysical characterization in the absence of protein led to emission maxima, singlet energies, quantum yields, and fluorescence lifetime values ... more
The photodissociation of H2O in its B band is a prototype for nonadiabatic reaction dynamics. In addition to dissociation via the adiabatic pathway to the OH(Ã2Σ+) + H fragments, it also produces the OH(X̃2Π) + H fragments through two nonadiabatic pathways: the B̃ → X̃ transition via two co ... more
Due to the widespread occurrence in the environment and potential risk toward organisms of fluoroquinolones (FQs), it is of importance to develop high efficient methods for assessing their occurrence and environmental risk. A monoclonal antibody (Mab) with broad cross-reactivity to FQs was ... more
Rohm and Haas Powder Coatings is delighted to announce that its Reading, Pennsylvania, facility is the first site in the world to receive the RCMS® Site Certification awarded by the American Chemical Council (ACC).
When Raj Gupta, Chairman and CEO of Rohm and Haas Company, became Chairman ... more