Publications by authors named "Raul Villamil-Ramos"
Article Synopsis
- A new dicationic diboronic acid structure was synthesized and tested as a fluorescent receptor specifically for sorbitol in water at pH 7.4.
- When sorbitol is added, it causes a significant increase in fluorescence, while other saccharides like fructose and glucose only produce minor changes.
- The study confirms that the receptor has a high affinity for sorbitol due to a specific binding mechanism, making it effective for selective saccharide recognition in biological contexts.
The binding types (H-bonding or coordinate) and stability constants for complexes of 11 mono- and di-anions with benzoxaborole () were determined by H and B NMR titrations in DMSO or MeCN. Compared to phenylboronic acid (PBA), is a stronger Lewis acid and a poorer H-bond donor with only one B-OH group, which is expected therefore to recognize anions mostly through the coordinate bonding. This is the case however only with F, HPO, and PhPO anions, which are coordinately bonded to , and partially with SO, which forms only the H-bonded complex with PBA, but both H-bonded and coordinate complexes with .
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- The study focuses on using a dimethyltin (IV)-catecholate complex for real-time detection of pyrophosphate (PPi) during polymerase chain reactions, distinguishing it from adenosine triphosphate (ATP).
- The dimethyltin (IV) complex forms a stable 1:1 structure with tiron and successfully isolates signals from PPi and ATP through fluorimetric and electrochemical methods.
- While ATP interferes with the detection of PPi in the fluorimetric method by forming a ternary complex, it can still be detected separately in the electrochemical method via a distinct peak, allowing for simultaneous monitoring of both molecules.
Article Synopsis
- The stability constants of boronic acid diol esters in aqueous solutions were analyzed, revealing a relationship with the acidity of diols and following Hammett's equation, with varying values (ρ) based on the specific diols used.
- Overlapping experimental methods, like UV-vis and NMR titrations, showed discrepancies in stability constant measurements, with UV-vis yielding higher values compared to NMR results.
- A proposed general equation allows for the estimation of stability constants based on the acidity (pKa) of the involved boronic acid and diol, enhancing the understanding of how other factors like sterics and charge impact ester stability.
3-Hydroxyflavonate-diphenyltin(IV) chloride (Ph(2)Sn(Ofl)Cl) was prepared and characterized structurally by single crystal X-ray diffraction. The compound possesses high fluorescence (λ(max) 464 nm with excitation at 400 nm) in neutral aqueous solutions containing 5 mM cetyltrimethylammonium chloride and does not lose the flavonol ligand even at high dilution. The fluorescence is selectively quenched by pyrophosphate (PPi) (linear range 0-5 μM, detection limit 0.
View Article and Find Full Text PDFHighly selective detection of pyrophosphate in the presence of inorganic phosphate, halides, acetate, ATP, other nucleotides and phosphate esters in neutral aqueous solutions is achieved by using fluorescent dimethyltin(iv)-alizarin red S complex.
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