Interaction of Caffeine with L-Tryptophan: Study by 1H Nuclear Magnetic Resonance Spectroscopy

Temporal Changes in Aroma Release of Longjing Tea Infusion: Interaction of Volatile and Nonvolatile Tea Components and Formation of 2-Butyl-2-octenal upon Aging

“…Also, the π-π stacking, which might occur between π-electrons of tea polyphenols and pyrazines or carbonyls (via the CdO double bond), might explain the interaction causing a decreasing release of these aroma compounds. Such a π-π stacking was reported in the complex formation between polyphenols and aromatic aroma compounds (35)(36)(37)(38)(39)(40)(41)(42). Finally, the polyphenol might be hydroxyalkylated in the presence of carbonyl compound as recently reported by Totlani and Peterson (43).…”

Chiral Separation of Underivatized Amino Acids by Reactive Extraction with Palladium−BINAP Complexes

“…The UV−vis spectra shown in Figures and show the effect of increased complexation of d -Trp to the palladium complex. An isosbestic point is maintained at 328 nm, which slightly shifts, probably due to a small absorption of Trp at this wavelength . Above 328 nm, titration with d -Trp results in a decrease in the absorption of the palladium complex.…”

NMR analysis of ion pair formation between timolol and sorbic acid in ophthalmic preparations

“…The changes in the chemical shifts of carbon provided powerful evidence of ion pair formation by timolol. Several previous NMR studies on the interactions of compounds involving aromatic rings have reported plane-plane stacking based on -electron systems [23]. The thiadiazolyl group of timolol, and both sorbic acid and maleic acid contain more than one double bond (Fig.…”