Hydrogen bonding in solids correlation of spectroscopic and crystallographic data

The adsorption of formic acid and sodium formate on the stoichiometric anatase (101) surface has been studied by means of density functional calculations with a slab geometry. On the clean surface, the most stable adsorption structure for HCOOH is a molecular monodentate configuration, hydrogen bonded to a surface bridging oxygen, while for HCOONa a dissociated bridging bidentate geometry is preferred. The bidentate chelating structure is energetically unstable for both the acid and the salt. On the hydrated surface, both HCOOH and HCOONa preferentially form an inner-sphere adsorption complex. HCOOH maintains a monodentate coordination, but, due to the interaction with a nearby water molecule, it becomes dissociated, while HCOONa again prefers a bridging bidentate structure. The energies for adsorption from an aqueous solution are estimated to be 0.30 and 0.79 eV for HCOOH and HCOONa, respectively.

Formic Acid Adsorption on Dry and Hydrated TiO2 Anatase (101) Surfaces by DFT Calculations

Recent developments in sulfone chemistry

1
A low-molecular-weight and a high-molecular-weight 1,4-β-glucan glucanohydrolase (Cx enzyme) have been isolated from a commercial cellulase preparation derived from culture filtrates of the fungus Trichoderma viride.

2
The purification method for the isolation of the low-molecular-weight enzyme is a three-step procedure including chromatography on Bio-Gel P-10, chromatography on a dipolar adsorbent (arginine-Sepharose 6B) and isoelectric focusing.

3
The starting material for the isolation of the high-molecular-weight enzyme was pre-fractionated by chromatography on Bio-Gel P-10, by DEAE-Sephadex chromatography and by SE-Sephadex chromatography as described previously by us. Further fractionation of this material was achieved by affinity chromatography and repeated isoelectric focusing.

4
Free zone electrophoresis of the low-molecular-weight enzyme indicated a homogeneous protein. The high-molecular-weight enzyme was homogeneous in sedimentation equilibrium analysis.

5
The molecular weights of the enzymes were 12500 and 50000 ± 2000 respectively. The former value was determined by chromatography on a calibrated column of Bio-Gel P-100 and the latter value by sedimentation equilibrium analysis.

6
The low-molecular-weight enzyme was isoelectric at pH 4.60 (10 °C) and contained 21% carbohydrate. The corresponding values for the high-molecular-weight enzyme were pH 3.39 and 12%.

7
Both enzymes were active in releasing free fibers from filter-paper. The low-molecular-weight enzyme was estimated to be about twice as effective as the high-molecular-weight enzyme in this regard.

https://febs.onlinelibrary.wiley.com/doi/pdf/10.1111/j.1432-1033.1974.tb03621.x

The Mechanism of Enzymatic Cellulose Degradation

copper proteins systems containing the “Blue” copper center

/pdf/a-reinvestigation-of-the-structure-of-monomer-and-dimer-3e5m0zg0uq.pdf

A Reinvestigation of the Structure of Monomer and Dimer Formic Acid by Gas Electron Diffraction Technique.

/pdf/study-of-the-influence-of-deuterium-substitution-on-the-bbtp1nhh2b.pdf

Study of the influence of deuterium substitution on the hydrogen bond of dimeric formic acid.

/pdf/transfer-of-triplet-state-energy-in-fluid-solutions-iv-246c418qw1.pdf

Transfer of Triplet State Energy in Fluid Solutions. IV. Determination of Triplet Yields by the Measurement of Sensitized Biacetyl Phosphorescence.

/pdf/isoelectric-fractionation-analysis-and-characterization-of-15h6lhy107.pdf

Isoelectric Fractionation, Analysis, and Characterization of Ampholytes in Natural pH Gradients. IX. A Method for Obtaining pH Gradients in the Region Below pH 3, Stable Enough to Permit Isoelectric Focusing of Ampholytes.

/pdf/electrolytic-cleavage-of-beta-ketosulfones-a-convenient-1v985ebmax.pdf

Tove Motzfeldt

Papers

A Reinvestigation of the Structure of Monomer and Dimer Formic Acid by Gas Electron Diffraction Technique.

Study of the influence of deuterium substitution on the hydrogen bond of dimeric formic acid.

Transfer of Triplet State Energy in Fluid Solutions. IV. Determination of Triplet Yields by the Measurement of Sensitized Biacetyl Phosphorescence.

Isoelectric Fractionation, Analysis, and Characterization of Ampholytes in Natural pH Gradients. IX. A Method for Obtaining pH Gradients in the Region Below pH 3, Stable Enough to Permit Isoelectric Focusing of Ampholytes.

Electrolytic Cleavage of beta-Ketosulfones. A Convenient Ketone Synthesis.