Methyl coupling

It is of interest to compare the markedly different methyl coupling constants in the positive and negative ions of 9,10-dimethylanthracene with those found in neutral alkyl radicals. Various methods of comparison suggest that the value of 8-0 G for the cation is close to that expected if the proportionality constant is about equal to that for the... 

Figure 38 The evolution of the contribution of methyl lone pairs to the DOS of a chemisorption system (CH3) on Co(0001) as the two methyls couple to give ethane. 6 is defined at top. Note the development of two peaks corresponding to a and <7 of the CC bond in ethane.

N-methyl coupling constants in acyclic and cyclic quartemary ammonium iodides ... 

Dynasylan 1505 Dynasylan 1506 EINECS 221-660-8 cr-Aminopropylmethyldiethoxysllane KBE 902 1-Propanamine, 3-(dlethoxymethylsilyl)- Propylamine, 3-(dlethoxymethylsilyl)- Silane, 3-aminopropyl)diethoxy-methyl-. Coupling agent, chemical... 

The catalytic oxidation of toluene over metal oxides to benzaldehyde and benzoic acid are well-known industrial processes and minor amounts of coupling products are detected among the products. It is shown that the oxidative coupling of toluene is favoured under anaerobic conditions and that metal oxides of the groups III to V of the periodic table catalyse methyl-methyl coupling [1]. Pb/Li/MgO is chosen for this study because it is known as a selective catalyst for the oxidative methylation of toluene with methane [2-4] and as good benzyl radical producer [1]. 

II, Figure 2) 15, 19). The temperature dependencies of the relaxation rates of the methyl protons of pyruvate have been fit by an exchange contribution (1/tjj/), a Tui contribution, and an upper limit for T2m> from which the kinetics of pyruvate binding and dissociation see Table V) (Figure 3), the Mn-to-methyl distances (Figure 1), and a lower limit to the Mn-to-methyl coupling constant (Table IV) have been evaluated. 

The coupling constant for the methylene-hydroxyl interaction is found to be (CH2, OH) = ca. 5 Hz. The methyl triplet is found to have a different coupling constant, (CH3, CH2) = ca. 7 Hz., for the methylene-methyl coupling. The methylene protons are not split into a quintet by their four neighbors, as the couphng constants for hydroxyl-methylene and methyl-methylene are different. As noted in Chapter 5, the n -t 1 Rule does not apply in such an instance each interaction occurs independently of the other, and a graphical analysis is required to approximate the correct pattern. 

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