Thermal and Spectroscopic Study of Dehydration of Lithium Formate Monohydrate Single-crystals

Differential scanning calorimetry (DSC) and thermogravimetric analysis (TG) of lithium formate monohydrate (LiHCOO·H₂O) were performed in the temperature range 300–700 K. The DSC/TG measurements show that the dehydration process to anhydrous lithium formate (LiHCOO) is complex and occurs in two stages. The data are correlated to the structure and to the arrangement of the molecules in the crystal, including the hydrogen-bonding. Infrared transmittance and Raman spectra of this crystal are reported and commented on. This revised version was published online in July 2006 with corrections to the Cover Date.     

Evaluation of Isoprene Chain Extension from PEO Macromolecular Chain Transfer Agents for the Preparation of Dual, Invertible Block Copolymer Nanoassemblies

Two RAFT-capable PEO macro-CTAs, 2 and 5 kDa, were prepared and used for the polymerization of isoprene which yielded well-defined block copolymers of varied lengths and compositions. GPC analysis of the PEO macro-CTAs and block copolymers showed remaining unreacted PEO macro-CTA. Mathematical deconvolution of the GPC chromatograms allowed for the estimation of the blocking efficiency, about 50% for the 5 kDa PEO macro-CTA and 64% for the 2 kDa CTA. Self assembly of the block copolymers in both water and decane was investigated and the resulting regular and inverse assemblies, respectively, were analyzed with DLS, AFM, and TEM to ascertain their dimensions and properties. Assembly of PEO-b-PIp block copolymers in aqueous solution resulted in well-defined micelles of varying sizes while the assembly in hydrophobic, organic solvent resulted in the formation of different morphologies including large aggregates and well-defined cylindrical and spherical structures.     

The reaction of spiro[indoline‐naphthopyrans] with nitrogen oxides. Not a case of biradical double trapping

The reactions of six differently substituted photochromic spiro[indoline‐naphtopyrans] with ·NO or ·NO₂ under normal daylight conditions have been investigated by means of EPR spectroscopy along with those of three structurally related spiro[indoline‐benzopyrans]. The spectra due to cyclic oxynitroxides originating from double trapping of biradicals by ·NO were observed with the three latter derivatives, this finding being in agreement with previous results. Similar signals were also observed with the six former compounds, but in this case they were responsible for just a minor component of the spectra, the main spectral signals being due to hitherto unreported paramagnetic species that on the basis of their spectral parameters are identified as iminoxy radicals. DFT calculations at the B3LYP/6‐31G* level carried out on a variety of radicals support this assignment. Copyright © 2009 John Wiley & Sons, Ltd.     

An Efficient Hydroxymethylation of Lactams

N-Hydroxymethylation of lactams was achieved using paraformaldehyde in acetone in the presence of K₂CO₃ and water under sonication conditions.     

An alternative view on the kinetics of optical stimulated luminescence decay

In this work, it was made similitude between radioactive decay and luminescence decay. An alternative approach related with the radioactive decay law of successive disintegrations from a composite radioactive material to describe the optical stimulated luminescence (OSL) decay curve was introduced. The modified radioactive decay law was applied to find the individual components of the different synthetic and experimental OSL decay curves. The suggested relation was named as “Active-OSL Approximation”. This work offers an alternative view on the kinetics of OSL decay.