2-MTHF

Ito and Matsuda studied the y-radiolysis of 2-methyltetrahydrofuran (MTHF) solutions of diphenyl sulfone and dibenzothiophene-S,S-dioxide (DBTSD) at 77 K. They found that the radical anions of these sulfone compounds are formed and have intense absorption bands at 1030 nm and 850 nm, respectively. The blue glassy solution of y-irradiated diphenyl sulfone has absorption bands at both 1030 nm and 360 nm while the absorption spectrum of the benzenesulfonyl radical formed by UV irradiation of diphenyl sulfone solution at 77 K showed only a peak at 382 nm. Gamma-irradiated phenyl methyl sulfone solution showed an absorption band only at 385 nm. Consequently the appearance of the absorption bands in 800-1030 nm of diphenyl sulfone and DBTSD may suggest that the unpaired electron is delocalized on two phenyl rings. The same authors studied the radiolysis of MTHF solutions of disulfones (diphenyl and dihexyl disulfones). They found a blue coloring of the solution by the y-radiolysis of diphenyl disulfone and dihexyl disulfone due to absorption peaks at 695 nm and 690 nm respectively, besides smaller absorptions at 300-400 nm. Comparing these results to the previous observation, that phenyl methyl sulfone solution absorbs only at 398 nm, results in the conclusion that the absorption band at 690 nm is due to the linked two sulfone moieties. The authors found that substituents on the phenyl ring lead to shifts in the absorption maxima of the... 

Specific Electron Capture. It is now customary to use solvents such as methanol (usually CD3OD) or methyl tetrahydrofuran (MTHF) as solvents if electron-capture by AB is required. These solvents form good glasses at 77 K, and for sufficiently dilute solutions of the substrate, AB, electron ejection occurs overwhelmingly from solvent molecules, so that AB+ centres are not formed. Electrons are fairly mobile, and hence AB radicals are formed provided AB has, effectively, a positive electron affinity. The hole centres, such as CD30D+, are not mobile because proton transfer to surrounding solvent molecules occurs rapidly at all temperatures. 

Fig. 4 Esr spectra of high-spin trianthrylene [21a] at 120 K in MTHF/K A, biradical triplet state [21a]2- (labelled O) B, triradical quartet state [21a]3- (labelled ) C, biradical triplet state [21a]4- (labelled ).

Fig. 7 Esr and ENDOR spectra of 1,2-dianthrylethane [6a] for different ion-pair conditions A, DME/HMPA, K + B, MTHF, K+ at 190 K in solution.

Gasoline (Cj-Ct)) Butanol Ethanol Methanol MTHF (methyltetrahydrofuran) MTBE (methyl tertiary-butyl ether) Deoxygenated and refined primary bioliquids... 

Tetracarbene [24 wi = 4] has been generated in a 2-methyltetrahydro-furan (2-MTHF) matrix and analysed based on (9) to give preliminary data g = 2.0030, D = 0.01400 and E = 0.00050 cm with 5 = 4. Note that the -value of the last compound is almost vanishing due to the cylindrical symmetry of the molecule. 

The isomeric stilbene dicarbenes [20] were generated in 2-MTHF matrices in an epr cavity at 16 K (Murata et ai, 1987 Iwamura, 1988). The spectra obtained by the photolysis of the diazo-compounds [20a], precursors to m,p -[20] and w,m -[20], at 16 K exhibited conspicuous signals at ca. 250 mT, characteristic of quintet species. The signals of /w,w -[20] showed a dramatic temperature dependence (Fig. 16). First, their intensity increased as the temperature was raised, reaching a maximum at SO K, and then decreased somewhat and eventually irreversibly at above 65 K. In contrast, the intensity of the strong signal at ca. 250 mT and some weak signals due to m,p -[20] decreased linearly with the reciprocal of the temperature as dictated... 

Among the three isomers of bis(phenylmethylenyl) [2.2]paracyclophanes [38], pseudo-ort/jo- and pseudo-para-isomers (o-[38j and p-[38], respectively) satisfy McConnell s condition to give quintet ground states. They were produced by photolysis of the corresponding bis(a-diazobenzyl)[2.2]para-cyclophanes [38a] in 2-MTHF at cryogenic temperatures, and their esr fine structures were studied. 

For example, when a solid solution of o-[38a] in 2-MTHF was irradiated with Pyrex-filtered light in an esr cavity at 11 K, a set of intense esr signals was obtained as shown in Fig. 22. The spectrum as a whole resembles that of See the Appendix on p. 245 of suffixes to structural formula numbers. 

Fig. 9.4 Improvements in potency of N-tosyl-D-proline. Structural analyses revealed that the glutamate moiety from the mTHF cofactor could be appended to the hit from Tethering, and further elaboration led to a submicromolar inhibitor.

As mentioned in the beginning of this section, m-phenylenecarbenonitrene (33) was found by ESR spectroscopy to have a quintet ground state. At that experiment, the carbenonitrene was produced by irradiation of 33-DN in a 2-methyltetrahydrofuran (MTHF) matrix at 18 K [97]. Interestingly enough, when the same precursor was irradiated under similar conditions (Ar matrix, 13 K ... 

In the more sterically hindered ether, 2-methyltetrahydrofuran (MTHF), the change in QSC is larger, varying from 60 kHz at —70 °C to 180 kHz at 60 °C. This is in accordance with a larger amount of CIP already at —70 °C compared to THF solution, as also shown earlier by other methods . In DEE, the QSC value varies between 220 kHz at —20°C and 150 kHz at 56 °C. In this case, the QSC value decreases at higher temperatures. This effect is not fully understood, but aggregation phenomena were suggested as an... 

The molar conductance of MTHF solutions of alkali metal-arene adducts (M+A , M+2A ) was measured for A = anthracene, tetracene, pentacene, biphenyl, p-terphenyl... 

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