Solution co-crystallization

Sonication is also another method of generating co-crystals. It is applied to a solution or suspension. Although this technique is little used in co-crystal screening, a recent study has shown that pure co-crystals could be obtained using ultrasound assisted solution co-crystallization, where conventional solution crystallization failed. he use of melt crystallization methods have also been reported as efficient co-crystal screening methodologies. These techniques include thermal microscopy" " and differential scanning calorimetry methods." ... 

In the preparation of the nitrosochloride, Wallach proposed to use pinene in glacial acetic acid and amyl nitrite. Ehestadt has recently proposed the following method, which is very simple and yields excellent results The pinene (or oil of turpentine) is diluted with its own volume of ether, the solution cooled with ice, and the gas generated hy dropping a saturated solution of sodium nitrite into concentrated hydrochloric acid passed through the solution. Fine crystals of pinene-nitrosochloride soon commence to separate out. Schimmel Co. obtained the following yields of nitrosochloride by the methods quoted —... 

The remarkable strength of some XBs allows them to prevail over HBs in identifying the modules to be involved in self-assembly. For instance, in experiments of competitive co-crystal formation, a dipyridyl derivative prefers to co-crystallize with XB donors rather than HB donors and the same occurs for NjNjN jN -lclramclhylclhylcncdiaminc (TMEDA) [36]. In solution, solute-solute intermolecular HBs are considerably diminished if a strong XB donor co-solute is added. If haloperfluorocarbons (halo-PFCs) are used, the HB breaking potency increases moving from perfluorocarbons to chloro-, bromo-, and iodoperfluorocarbons [37-43], perfectly consistent with the order of the increasing XB donor ability of the halo-PFCs co-solutes, hi aque-... 

Solutions of the analyte and the matrix (from nanolitre to microlitre amounts) are deposited or spotted on a flat metal target plate. Owing to evaporation of the solvent, matrix and analyte co-crystallize. Short laser pulses (1 20 ns) bombard the solid and cause the sample and matrix to be volatilized. The formation of ions occurs by acid base reaction between the ionized matrix molecules and the analyte molecules (Figure 2.5). 

Another functionalized alcohol, namely 2-aziridineethanol (azol), reacted with diethylzinc to yield almost quantitatively the ethylzinc alkoxide EtZn(azol), which is trimeric in solution.216 The introduction of dry dioxygen into solutions of EtZn(azol) gave the peroxoethylzinc alkoxide EtOOZn(azol), which co-crystallized with EtZn(azol) in a 1 1 ratio as a face-sharing di- o-heterocube 150 (Figure 70). 

FIGURE 15.2 Common protein ionization methods used for MS-based proteomics. Two common ionization technologies are currently available for protein analysis. Top ESI volatilizes and ionizes peptides and proteins in solution. Bottom MALDI uses analytes that are co-crystallized in a matrix composed of organic acid on a solid support. A pulse of ultraviolet laser evaporates the matrix and analyte into gas phase, resulting in generation of single charge ions. 

Solution and crystal IR and Raman data for (r)2-maleic anhydride)Fe(CO)4 and their assignment... 

Raman and IR spectra of solutions and crystals of S2Fe2(CC 6 and (CH3S)2Fe2(CO)6 together with vibrational analyses... 

A96 Butler, I. S., Shaw, C. F. J. Raman. Spect. 3, 65 (1975) Raman and IR solution and crystal spectra ofW(CO)4NOBr are analyzed (data from natural abundance 13CO-containing species are included)... 

Note The conventional co-crystallization is usually termed dried droplet preparation. The original thin layer technique involves preparation of a thin HCHA layer from solution in acetone on top of which the analyte is placed in a second step without re-dissolving the matrix. [95,97]... 

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