Electronic Spectroscopy of 2-Phenyl-1,3,2-benzodioxaborole and Its Derivatives: Important Building Blocks of Covalent Organic Frameworks.

Aryl boronate esters, such as 2-phenyl-1,3,2-benzodioxaborole (), are important components in the formation of a variety of covalent organic frameworks. The addition of substituents on the aromatic rings of aryl boronate esters has the potential to modify the structure, reactivity, and electronic properties of the resulting materials, and so, it is useful to understand at a more fundamental level the properties of these important compounds. Experimental measurements and computational investigations are presented herein that provide insight regarding the structural and electronic properties of parent aryl boronate ester as well as three substituted derivatives: 2-(-tolyl)-1,3,2-benzodioxaborole (), 2-(2,6-dimethylphenyl)-1,3,2-benzodioxaborole (), and 2-(4-(-butyl)phenyl)-1,3,2-benzodioxaborole ().

Quantitative probing of subtle interactions among H-bonds in alpha hydroxy carboxylic acid complexes.

Hydrogen (H) bonds are of fundamental importance in a wide range of molecular sciences. While the study of two-center H-bonding AH is well advanced, much remains to be learned in a quantitative and definitive manner for complexes with multiple H-bonds. Exemplary cases are in the category of alpha hydroxy carboxylic acids, i.

Communication: Physical origins of ionization potential shifts in mixed carboxylic acids and water complexes.

The ionization potential (IP) of the aromatic alpha hydroxy carboxylic acid, 9-hydroxy-9-fluorene carboxylic acid (9HFCA), is shifted by complexation with hydrogen bonding ligands such as water and formic acid. Generalized Kohn-Sham energy decomposition analysis decomposes the intermolecular binding energies into a frozen energy term, polarization, correlation, and/or dispersion energy terms, as well as terms of geometric relaxation and zero point energy. We observe that in each dimer the attractive polarization always increases upon ionization, enhancing binding in the cation and shifting the IP toward the red.

Characterization of two adenosine analogs as fluorescence probes in RNA.

The fluorescence properties of two adenosine analogs, 2-(3-phenylpropyl)adenosine [A-3CPh] and 2-(4-phenylbutyl)adenosine [A-4CPh], are reported. As monomers, the quantum yields and the mean lifetimes are 0.011 and 6.

Characterization of the dynamics of an essential helix in the U1A protein by time-resolved fluorescence measurements.

The RNA recognition motif (RRM), one of the most common RNA-binding domains, recognizes single-stranded RNA. A C-terminal helix that undergoes conformational changes upon binding is often an important contributor to RNA recognition. The N-terminal RRM of the U1A protein contains a C-terminal helix (helix C) that interacts with the RNA-binding surface of a beta-sheet in the free protein (closed conformation), but is directed away from this beta-sheet in the complex with RNA (open conformation).