DMSO solvate

Samples are taken directly from 10 mM DMSO-solvated stocks in 96-well plates. Typically, 2 pL of sample is aspirated, and injected on to the column - this represents about 8 pg of sample with MW = 400. The retention time (R,) of peaks eluting from the column is related to the capacity factor log k by Eq. (8) ... 

Oil the other hand, the paH of picric acid/picrate buffers in AN are not much influenced by water and alcohols of up to 0.5 M, because, in the buffers, homo-and heteroconjugation reactions do not occur appreciably [12]. In protophilic DMSO, the influences of hydrogen bond donors and acceptors on the paH of buffers are smaller than in protophobic AN. DMSO solvates to hydrogen bond donor HR, and suppresses the heteroconjugation, while DMSO suppresses the influence of a hydrogen bond acceptor by competing with it. 

The stability of DMSO solvates of AgCl04 have been measured in a range of solvents.271 Formation constants are presented in Table 37. In general, the complexes were found to be more stable than the corresponding DMF species (see Section 54.1.4.8.ii). 

Remember. DMSO solvates K but not R0 so R0 is left as a reactive naked anion . 

Ruthenium tetroxide was shown to oxidize PCBs in water [20], Water-soluble ruthenium complexes, such as [Ru(H20)2(DMS0)4]2+, are effective catalysts for the KHSO5 deep oxidation of a number of chloroaliphatics, of a-chlorinated al-kenes, polychlorobenzenes, and polychlorophenols. When the reactions are carried out in water in the presence of surfactant agents, degradation of the substrates is definitely faster. Aromatic substrates are mainly converted into HC1 and C02, polychlorophenols being more sensitive to oxidation than substituted benzenes [21]. Replacement of the DMSO- solvated ruthenium by RuPcS results in a definite improvement of the reaction course with hydrogen peroxide, since dismutation of... 

RUO4 was shown to oxidize PCBs in water [21]. Water-soluble Ru complexes, such as [Ru(H20)2(dmso)4], were effective catalysts for the KHSO5 oxidation of a number of polychlorobenzenes and polychlorophenols, mainly converted into HCl and CO2 [22]. Replacement of the dmso- solvated ruthenium by RuPcS resulted... 

Figure 9.8. Dependence of equilibrium constant for the formation process of addition product DMSO to o-cresol on permittivity in solution based on heptylchloride (o), ethyl acetate (x) and nitromethane ( ) - resolvation of o-cresol solvated in ethyl acetate in DMSO in mixed solvent CCVethyl acetate 2 -resolvation of DMSO solvated in nitromethane in o-cresol in mixed solvent CCLj-ititromethane 3 - process [9.84] in mixed solvent CCVltsptylchloride 4 -solvation of o-cresol in ethyl acetate 5 - solvation of DMSO in nitromethane.

The AgN03-H20-DMS0 system behaves in a different manner to the corresponding acetonitrile system [Cl 73]. In this system the effect of the DMSO on the water structure appears so predominantly in the NMR spectrum that the line shift characteristic of the DMSO solvate of silver shows up only at high DMSO concentrations. Hence, the measurement cannot be utilized to draw conclusions on the composition of this solvate. 

The composition of the DMSO solvate can be interpreted more unambiguously in the AgC104-CH30H-DMS0 system [Ro 76]. From the dependence of the chemical shift on the AgC104 concentration and on the composition of the mixed solvent, it could be established that the silver ion coordinates four DMSO molecules at most. 

The separation of enantiomers of racemic amlodipane (AML) with (R,R)-tartaric add by fractionated crystallization of diastereomers from the common solvents was without success, but in DMSO, however, the salt of (S)-AML crystallizes as a DMSO solvate. Even more surprisingly, in N,N-dimethyl-acetamide it is the solvate of the (R)-AML salt which crystallizes in good yield and high pHirity. ... 

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