Conversion of methanol to 2,2,3-trimethylbutane (triptane) over indium(III) iodide.

InI3 is able to catalyze the conversion of methanol to a mixture of hydrocarbons at 200 degrees C with one highly branched alkane, 2,2,3-trimethylbutane (triptane), being obtained in high selectivity. The mechanism for InI3-catalyzed reactions appears to be basically the same as that proposed for the previously studied ZnI2-catalyzed system in which sequential methylation of olefins is followed by competing reactions of the resulting carbocation: proton loss to give the next olefin vs hydride transfer to give the corresponding alkane. Although the reaction conditions and typical triptane yields achievable with ZnI2 and InI3 are quite similar, the two systems behave rather differently in a number of important particulars, including significant differences between the detailed product distributions.

On the mechanism of the conversion of methanol to 2,2,3-trimethylbutane (triptane) over zinc iodide.

Methanol is converted to a mixture of hydrocarbons by reaction with zinc iodide at 200 degrees C with one highly branched alkane, 2,2,3-trimethylbutane (triptane), being obtained in surprisingly high selectivity. Mechanistic studies implicate a two-stage process, the first involving heterogeneously catalyzed formation of a carbon-carbon-bonded species, probably ethylene, that undergoes homogeneously catalyzed sequential cationic methylation to higher hydrocarbons. The first stage can be bypassed by addition of olefins, higher alcohols, or arenes, which act as initiators.

Template Assembly of Metal Aggregates by Imino-Carboxylate Ligands.

Lanthanide, main group, and transition metal ion templates provide different polynuclear cages from [M(L)] (M=Ni, Mn; (L)=CH[CHN=C(CH)COO]). Templating with lanthanum results in a 12-coordinate La ion encapsulated by six [Ni(L)] units, whereas with sodium four Na ions are trapped inside a tricapped trigonal prismatic [{Ni(L)}] cage. With manganese, an octahedrally coordinated Mn ion is surrounded by six [Mn(L)] fragments in a twisted trigonal-prismatic configuration (see picture).